Instrumental and Sensory Quality of Fallow Deer (Dama dama ...

Instrumental and Sensory Quality of

Fallow Deer (Dama dama) and Red

Deer (Cervus Elaphus) Venison.

by

Christine Louise Hutchison

A thesis submitted in fulfilment of the requirements for the degree of

Doctor of Philosophy

University of Western Sydney School of Science and Health

2012

STATEMENT OF AUTHENTICATION

The work presented in this thesis is, to the best of my knowledge and

belief, original, except as acknowledged in the text. I hereby declare that

I have not submitted this material, either whole or in part, for a degree at

this or any other institution.

Christine Louise Hutchison, B.Ed., M.App.Sci. 3rd June, 2012

Acknowledgments

I would firstly like to thank my principal supervisor, Professor Robert Mulley. Rob

has provided an endless supply of support, patience, encouragement and wisdom

over the duration of my PhD candidature. Without Rob I would not have managed to

juggle the responsibilities of full time work, part time study and a young family quite

as I have. Also, thanks to my supervisory panel: Dr Jim Bergan, Emeritus Professor

Paul Baumgartner and Dr Rosalie Durham for their advice and expertise.

Thank you to Katrina Marshall and Professor David Laing for their assistance with

the sensory work. Thanks also go to Oleg Nicetic for his support with statistical

aspects of the project and to Dr Eva Wiklund and Dr Jason Flesch for assistance

during the experimental phase. I need to especially thank my family for their love,

support and hours of childcare provided during the project. I could not have done it

without you. I also wish to acknowledge my four children, Sarah, Laura, Mitchell

and Alexander, all born during the period of candidature, for their love and laughter

and making life interesting.

I also wish to acknowledge the support of the Rural Industries Research and

Development Corporation and the Deer Industry Association of Australia for funding

experimental work which formed the basis of the project. The animals used in this

study were sourced from Ward Holdings (fallow deer), Barry and Fay Dalton, Ian

and Heather Dowsett (red deer) and the University of Western Sydney. Industry

partners who assisted with processing include Myrtleford abattoir and Wodonga

abattoir. Mr Tim Hansen of Mandagery Creek Australian Farmed Venison assisted

with organisation of red deer slaughter and recovery of selected meat cuts.

Author‟s eldest child with a fallow deer fawn at the UWS Deer Research Unit

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Table of Contents TABLE OF CONTENTS i LIST OF TABLES vi LIST OF FIGURES ix LIST OF PLATES xi LIST OF ABBREVIATIONS xiv LIST OF TERMINOLOGY xviii LIST OF SPECIFIC NAMES xx PUBLICATIONS ARISING FROM THIS STUDY xx ii PRESENTATIONS ARISING FROM THIS STUDY xxiv ABSTRACT xxvi CHAPTER 1 General introduction 1

1.1: Background 2

1.2: Study aim 4

1.3: Experimental approach 4

1.4: Structure of the thesis 5

CHAPTER 2 Literature review 7

2.1: Venison production 8

2.1.1: History of deer as a meat species 8

2.1.2: Deer in Australia 8

2.1.3: Deer farming and venison production 9

2.1.4: Venison in the human diet 14

2.1.5: Current markets 18

2.1.6: Venison specifications 26

2.2: Measures of meat quality 28

2.2.1: Meat from muscle 28

2.2.2: Factors affecting meat quality 32

2.2.3: Consumer perception 49

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2.2.4: Beef and sheep meat quality improvement schemes 51

2.2.5: Estimations of body condition 57

2.3: Industry issues 62

2.3.1: Background 62

2.3.2: Current venison issues 67

2.3.3: Strategic industry alliances 73

CHAPTER 3 General materials and methods 76

3.1: Research environment and practices 77

3.1.1: University of Western Sydney deer research facilities 77

3.1.2: UWS fallow deer handling facilities 78

3.1.3: UWS abattoir facilities 80

3.1.4: Commercial abattoir description 81

3.1.5: UWS food processing facilities 82

3.1.6: UWS sensory evaluation and analysis facilities 82

3.1.7: Livestock and management 83

3.2: Meat quality analysis and procedures 85

3.2.1: pH 85

3.2.2: Intramuscular fat 85

3.2.3: Shear force/instrumental tenderness 86

3.2.4: Colour 87

3.2.5: Moisture 88

3.2.6: Freeze/thaw drip loss/purge 88

3.2.7: Carcass core body temperature 88

3.3: Measurements of body condition score 89

3.3.1: Kidney fat index 89

3.3.2: Carcass and fat depth measurements 91

3.4 : Sensory evaluation and analysis 94

3.4.1: Experimental design 94

3.4.2: Cooking and preparation technique 95

3.5: Statistical analysis 96

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CHAPTER 4 Relationship between body condition score and meat

quality parameters of venison 97

4.1: Introduction 98

4.2: Materials and methods 117

4.2.1: Fallow bucks of BCS 2 to 3 117

4.2.2: Fallow does of BCS 2, 3 and 4 117

4.2.3: Fallow bucks and haviers (castrated bucks) 118

4.2.4: Red deer stags with BCS of 2, 3 and 4 118

4.3: Results 120

4.3.1: Fallow bucks of BCS 2 to 3 120

4.3.2: Fallow does of BCS 2, 3 and 4. 121

4.3.3: Fallow bucks and haviers 123

4.3.4: Red deer stags with BCS of 2, 3 and 4 125

4.4: Discussion 127

4.4.1: BCS and live weight 127

4.4.2: Intramuscular fat 128

4.4.3: Shear force 129

4.4.4: Freeze-thaw/purge 132

4.4.5: Colour 133

4.5: Conclusions 135

CHAPTER 5 Effect of concentrate feeding on meat quality

parameters of venison from fallow deer does 137



5.3: Results 142

5.4: Discussion 151

5.4.1: BCS 151

5.4.2: pHu 151

5.4.3: Freeze-thaw purge 152

5.4.4: Intramuscular fat and tenderness 152

5.4.5: Colour 153


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CHAPTER 6 Relationship between post-slaughter management

and meat quality parameters of venison 158

6.1: Relationship of carcass hanging time to meat quality 159

6.1.1: Introduction 159

6.1.2: Materials and methods 164

6.1.3: Results 164

6.1.4: Discussion 168

6.1.4.1: Tenderness and meat ageing 168

6.1.4.2: Intramuscular fat 169

6.1.4.3: Colour 170

6.2: Pelvic suspension vs. Achilles tendon hanging of carcasses 171


6.2.2 Materials and methods 175

6.2.2.1 Fallow Deer 175

6.2.2.2 Red Deer 176

6.2.3 Results 177

6.2.3.1 Fallow Deer Venison 177

6.2.3.2 Red Deer Venison 180


6.2.4.1: Shear force 181

6.2.4.2: Freeze-thaw purge 183

6.3: Differences between slaughter premises for muscle pH 184


6.3.2: Materials and methods 186

6.3.3: Results 186



CHAPTER 7 Effect of pre- and post-slaughter management

on the sensory parameters of venison quality 190



7.2.1: Sensory evaluation facility 198

7.2.2: Panellists 198

7.2.3: Sample preparation 198

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7.2.4: Sample testing 199

7.2.5: Data analysis 200

7.3: Results and discussion 201

7.3.1 Fallow deer (pasture-fed) 201

7.3.1.1 Experimental design 201

7.3.1.2 Results 201

7.3.1.3 Discussion 206

7.3.2: Fallow deer - Impact of Supplementary Feeding 208

7.3.2.1 Introduction 208


7.3.2.3 Results 210


7.3.3 Red Deer (pasture-fed) 215

7.3.3.1 Introduction 215


7.3.3.3 Results 217



CHAPTER 8 Conclusions and Recommendations for Industry 226

8.1 : Overall Conclusions 227

8.2 : Recommendations to Industry 229

REFERENCES 232

APPENDICES 275

Appendix 1: Australian Body Condition chart for fallow Deer 276

Appendix 2: Australian Body Condition Chart for Red Deer 277

Appendix 3: Body Condition Score chart for red deer 278

Appendix 4: Sensory Evaluation of Venison 280

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List of Tables Table 4.1: Meat quality attributes of M.longissimus dorsi from fallow

bucks of BCS 2 (n=16) and 3 (n=15). 121 Table 4.2: Meat quality attributes of M. longissimus dorsi from fallow

does of BCS 2 (n=7), BCS 3 (n=7) and BCS 4 (n=10). 123 Table 4.3: Meat quality attributes of M.longissimus dorsi from fallow

bucks and haviers of BCS 2 and 3. 124 Table 4.4: Meat quality attributes of M.longissimus dorsi from red stags

of BCS 2 (n=14), 3 (n=6) and 4 (n=6). 127 Table 5.1: BCS, weights and dressing percentages from fallow does

measured at either 135 or 170 days after commencement of feeding with concentrates (n=6 per group), compared with pasture-fed controls. 144

Table 5.2: pH over storage times from fallow doe venison measured at either 135 or 170 days after commencement of feeding with concentrates (n=6 per group), compared with pasture-fed controls. 147

Table 5.3: Percentage drip loss (purge) over storage times for fallow doe venison measured at either 135 or 170 days after commencement of feeding with concentrates (n=6 per group), compared with pasture-fed controls. 148

Table 5.4: Meat quality attributes of M.longissimus dorsi from fallow deer does with BCS 2, 3 and 4 fed on pasture or concentrates. 149

Table 5.5: Meat quality attributes of M.longissimus dorsi from fallow does measured at either 135 or 170 days after commencement of feeding with concentrates (n=6 per group), compared with pasture-fed controls. 150

Table 6.1: Meat quality attributes of M.longissimus dorsi from

fallow bucks and haviers with BCS between 2 and 3. 165

Table 6.2: Meat quality attributes of M.longissimus dorsi from fallow bucks and haviers with BCS between 2 and 3 measured at 5 days and 10 days post-mortem. 166

Table 6.3: Mean pH, moisture, shear force and intramuscular fat measurements for fore, mid- and hind loin samples for fallow bucks and haviers measured at 5 and 10 days post-mortem. 167

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Table 6.4: Meat quality attributes of M.longissimus dorsi from fallow bucks hung by the Achilles tendon and pelvic suspension methods (n=15). 179

Table 6.5: Meat quality attributes of M longissimus dorsi from fallow doe carcasses hung by either the Achilles tendon or by pelvic suspension (n=10). 180

Table 6.6: Meat quality attributes of M. longissimus dorsi from red stags hung by the Achilles tendon or pelvic suspension after slaughter (n=14). 181

Table 6.7: Ultimate pH of M.longissimus dorsi from fallow bucks slaughtered at three different slaughter plants. 186

Table 7.1: Mean (+/- SEM) sensory evaluation scores for venison

from fallow bucks (n=10) and does (n = 10). All panellists (n=42). 202

Table 7.2: Mean (+/- SEM) sensory evaluation scores for venison from fallow bucks (n=10) and does (n = 10), effect of panellist age (group 1 n=14, group 2 n=13, group 3 n=15) on determination of flavour strength. 202

Table 7.3: Mean (+/- SEM) sensory evaluation scores for venison from fallow bucks (n=10) and does (n = 10), effect of game eating experience (game eaters n=27, non game eaters n=15) on determination of flavour strength. 203

Table 7.4: Mean (+/- SEM) sensory evaluation scores for venison from fallow bucks and does with BCS of either 2 (n = 8) or 3 (n = 12). All panellists (n=42). 203

Table 7.5: Mean (+/- SEM) sensory evaluation scores for venison from fallow bucks and does hung by either the Achilles tendon or by pelvic suspension (n=20 of each), All panellists (n=42). 205

Table 7.6: Mean (+/- SEM) sensory evaluation scores for venison from fallow does fed on either pasture or grain prior to slaughter (n=12 per group). All panellists (n=42). 211

Table 7.7: Mean (+/- SEM) sensory evaluation scores for venison from fallow deer does with BCS ranging from 2 to 4. All panellists (n=42). 211

Table 7.8: Mean (+/- SEM) sensory evaluation scores for venison from fallow deer does (n=24) fed for either 135 or 170 days on grain, effect of panellist gender on determination of flavour strength. 212

Table 7.9: Mean (+/- SEM) sensory evaluation scores for venison from red stags hung by either the Achilles tendon or by pelvic suspension. 217

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Table 7.10: Mean (+/- SEM) sensory evaluation scores for venison from red stags with BCS of 2, 3 or 4 (n=12, 6 and 8 respectively). All panellists (n=42). 219

Table 7.11: Mean (+/- SEM) sensory evaluation scores for venison

from red stags with BCS of 2, 3 or 4 (n=12, 6 and 8 respectively), effect of panellist gender on determination of colour. 220

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List of Figures Figure 2.1: Australian deer processed and venison produced

(deer numbers estimated for 2009/2010) 25 Figure 2.2: Diagram of muscle and fibre structure (Ranken 2000). 29 Figure 2.3: Meat ageing. At x12500 magnification (A) Intact 1h post-mortem,

(B) 24h post-mortem some Z disk degradation, (C) 48h post-mortem Z disk degradation and myofibril breakage is extensive, at x650 magnification (D) 8 days post-mortem complete lateral breaks of myofibrils (Aberle et al 2001). 42

Figure 4.1: Live weights of the fallow bucks of BCS 2 and BCS 3 used

in this study. 120

Figure 4.2: Live weights of the fallow does of BCS 2, 3 and 4 used in this study. 122

Figure 4.3: Live weights of the fallow bucks and haviers of BCS 2 and BCS 3 used in this study. 124

Figure 4.4: Hot carcass weights of the red stags used in this study. 125 Figure 4.5: Fat depth (GR) of the red stags used in this study. 126 Figure 5.1: Comparison of weights and dressing percentages for fallow

does fed pasture or concentrates for 135 days prior to slaughter. 142 Figure 5.2: Comparison of weights and dressing percentages for fallow

does fed pasture or concentrates for 170 days prior to slaughter. 143 Figure 5.3: Temperature decline for carcasses from the fallow does

fed pasture or concentrates for 135 days prior to slaughter. 145 Figure 5.4: Temperature decline for carcasses from the fallow does

fed pasture or concentrates for 170 days prior to slaughter. 145 Figure 5.5: pH decline of M.Longissimus dorsi after 135 days of feeding. 146 Figure 5.6: pH decline of M.Longissimus dorsi after 170 days of feeding. 146 Figure 5.7: Drip loss following storage of venison from fallow does after

135 days of feeding. 147 Figure 5.8: Drip loss following storage of venison from fallow does

after 170 days of feeding. 148

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Figure 6.1: The pH /temperature window as it relates to meat tenderness. The solid line indicates optimal decline, the dashed line cold shortening and the dotted line heat shortening (Thompson 2002). 161

Figure 6.2: Diagram of pelvic suspended (left) and Achilles hung

carcass (Sorheim & Hildrum 2002). 170 Figure 6.3: Shear force mean values in 7 muscles (LD = M. longissimus,

BF = M. biceps femoris, ST = M. semitendinosus, SM = M. semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus femoris) from fallow bucks (18 months old, n=8). 178

Figure 6.4: Shear force mean values in 9 muscles (SS = M. supraspinatus,

PS = M. psoas major, LD = M. longissimus, BF = M. biceps femoris, ST = M. semitendinosus, SM = M. semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus femoris) from fallow bucks (36 months old, n=7). 178

Figure 6.5: Shear force mean values in 9 muscles (SS = M. supraspinatus,

PM = M. psoas major, LD = M. longissimus, BF = M. biceps femoris, ST = M. semitendinosus, SM = M. semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus femoris) from fallow does (≥24 months old, n=10). 179

Figure 7.1: Mean (+/- sem) sensory panel scores of meat colour for

venison from fallow bucks and does with BCS of 2 and 3. 204

Figure 7.2: Mean (+/- sem) sensory panel scores of overall liking of

venison from fallow bucks and does with BCS of 2 and 3 hung

by the Achilles tendon or by pelvic suspension. 205

Figure 7.3: Mean (+/- sem) sensory panel scores for flavour strength

of venison from fallow does with body condition scores of 3

and 4 fed either pasture or grain prior to slaughter. 212

Figure 7.4: Mean (+/- sem) sensory panel scores for tenderness, juiciness

and overall liking for venison from red stags with BCS between 2

and 3 hung post-mortem by the Achilles tendon or by

pelvic suspension. 218

Figure 7.5: Mean (+/- sem) sensory panel scores for tenderness of venison

from red stags with BCS 2, 3 or 4. Higher scores indicate more

tender meat. 219

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List of Plates Plate 2.1: Examples of AUS-MEAT venison language and descriptions for some bone-in cuts. 27 Plate 2.2: Examples of AUS-MEAT venison language and descriptions for some boneless cuts. 27 Plate 2.3: Split fallow deer carcass hung by the pelvic suspension technique. 39 Plate 2.4: Fallow deer carcass suspended by the Achilles tendon. 40 Plate 3.1: Aerial image of the Deer Research Unit at UWS Hawkesbury Campus 77 Plate 3.2: Diagram of the UWS Deer Research Unit located at the

Hawkesbury Campus of the University of Western Sydney (Flesch 2001). 78

Plate 3.3: Entrance to deer handling shed used in this study. 78 Plate 3.4: Deer handling shed at UWS. 79 Plate 3.5: Deer handling cradle used in this study. 79 Plate 3.6: Mezzanine view of deer in the handling shed at UWS. 80 Plate 3.7: Experimental abattoir at UWS. 81 Plate 3.8: Scales and meat rail leading to the chiller in the experimental abattoir. 81 Plate 3.9: Fallow deer carcasses in the chiller at UWS. 81 Plate 3.10: Food processing facilities at UWS. 82 Plate 3.11: Vacuum packaging equipment. 82 Plate 3.12: Individual tasting booth in the sensory evaluation facility at UWS. 83 Plate 3.13: Sensory facility preparation area. 83 Plate 3.14: Servery side of the individual tasting booths. 83 Plate 3.15: Hybrid fallow deer at UWS 84 Plate 3.16: Typical red deer stag at UWS. 84 Plate 3.17: Buchi apparatus for Soxhlet fat extraction. 86 Plate 3.18: Samples prepared for colour evaluation and shear testing. 87 Plate 3.19: Texture/shear analysis. 87

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Plate 3.20: Colour measurement using the Minolta chromameter. 87 Plate 3.21: Excised kidneys with channel fat removed (Flesch 2001). 90 Plate 3.22: Kidneys trimmed prior to decapsulation (Flesch 2001). 90 Plate 3.23: Kidneys prepared and denuded as described by Riney (1955). 90 Plate 3.24: Deer in handling cradle for live palpation to estimate BCS

(Flesch 2001). 91

Plate 3.25: Forequarter fat measurement area (Flesch 2001). 92 Plate 3.26: Loin fat measurement area (Flesch 2001). 92 Plate 3.27: Rump fat measurement area (Flesch 2001). 93 Plate 3.28: Brisket fat measurement area (Flesch 2001). 93 Plate 3.29: Venison samples prepared for serving. 95 Plate 3.30: Venison samples presented to panellists. 95 Plate 3.31: Panellists assessing venison samples. 96 Plate 4.1: Mature fallow deer doe of BCS 2. 105 Plate 4.2: Dorsal view of BCS 2 carcass. 106 Plate 4.3: Caudal view of BCS 2 carcass. 106 Plate 4.4: Cross sectional view of EMA of BCS 2 carcass. 107 Plate 4.5: Mature fallow deer buck of BCS 3. 107 Plate 4.6: Dorsal view of BCS 3 carcass. 108 Plate 4.7: Caudal view of BCS 3 carcass. 108 Plate 4.8: Cross sectional view of EMA of BCS 3 carcass. 109 Plate 4.9: Mature fallow deer bucks of BCS 4. 109 Plate 4.10: Dorsal view of BCS 4 carcass. 110 Plate 4.11: Caudal view of BCS 4 carcass. 110 Plate 4.12: Cross sectional view of EMA of BCS 4 carcass. 111 Plate 4.13: Mature red stag of BCS 4. 112

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Plate 4.14: Red stag carcass of BCS 4. 112 Plate 4.15: Red stags of BCS 2. 119 Plate 4.16: Red stags of BCS 3 and 4. 119 Plate 4.17: Split red stag carcasses of BCS 2 hanging in the chiller at Myrtleford abattoir. 119 Plate 5.1: Fallow doe in the handling cradle for palpation to assess BCS

over the rump. 141 Plate 6.1: Fallow deer carcass suspended by the Achilles tendon. 172 Plate 6.2: Fallow deer carcass suspended by the pelvic bone. 172 Plate 6.3: Whole fallow deer carcass suspended by the pelvic bone. 174 Plate 7.1: Panellist in individual tasting booth. 199

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List of Abbreviations

a* measurement of redness

ADP adenosine diphosphate

AMSA American Meat Science Association

ANOVA analysis of variance

AT Achilles tendon

ATP adenosine triphosphate

AUS-MEAT Authority for Uniform Specifications of Meat and Livestock

b* measurement of yellowness or greenness or vividness

BCS body condition score

BMF bone marrow fat

BSE bovine spongiform encephalopathy

BV breeding value

CCP critical control point

CEQ consumer eating quality

cm centimetre/s

CRC co-operative research centre

CSIRO Commonwealth Scientific and Industrial Research Organisation

CT scanning X-ray computed tomography

CWD chronic wasting disease

DFD dry firm and dark

DIAA Deer Industry Association of Australia

E European fallow deer (Dama dama)

eg for example

EMA Eye muscle area

EQ eating quality

EQS eating quality standards

EU European Union

EUROP Five point scale for assessment of body conformation and fatness

et al. et alia

etc et cetera

F force

FMD foot and mouth disease

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g gram

GenStat statistical package

GLM generalised linear model

GM M.gluteus medius (rump)

GR fat depth Measurement of depth of fat at the GR site

GR site Site over the 12th rib at a vertical point down from the tuber coxae

(hip bone), 16cm out from the back bone

GVP gross value of production

h hour

H hybrid fallow deer (¼ Mesopotamian, ¾ European)

Ha hectares

HCW hot carcass weight

Hd head

IM intramuscular

IMF intramuscular fat

ISO International Organisation for Standardisation

JMGA Japanese Meat Grading Association

KFI kidney fat index

kg kilogram

L* measurement of lightness

Lab* colour measurement system

LD M.Longissimus dorsi (strip loin)

LW live weight

M molarity

m metre/s

MAXFAT ultrasonic technique of measuring rump fat thickness (US)

mg milligram

ml millilitres

mm millimetres

MQ meat quality

MQ4 composite meat quality score

MSA Meat Standards Australia

N nitrogen

n number

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NS not significant

NSW New South Wales

NZ New Zealand

p statistical probability

PACCP palatability assured critical control point

pH acidity/alkalinity

pHi initial pH

pHu ultimate pH

ppm parts per million

PS Pelvic suspension (Tenderstretch)

PSE pale soft and exudative

PUFA polyunsaturated fatty acids

P8 rump site for fat depth measurement

QA quality assurance

QAMA quality assurance management and analysis

R&D research and development

RDI recommended daily intake

RIRDC Rural Industries Research and Development Corporation

SCW standard carcass weight

sd standard deviation

sec second

sem standard error of the mean

SmartStretch technique of stretching and shaping hot boned primals

SMEQ sheep meat eating quality

SPSS statistical package

TQM total quality management

UK United Kingdom

USA United States of America

USDA United States Department of Agriculture

UWS University of Western Sydney

VIAScan Video image analysis scanning system

VIC Victoria

WHC water holding capacity

wt weight

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¼ M ¼ Mesopotamian fallow deer

< less than

> greater than

= equals

plus or minus variance around the mean

% percent

° degree

°C degrees Celsius

$A value in Australian dollars

$NZ value in New Zealand dollars

£ value in pounds sterling

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List of Terminology

Term Meaning

adipose fatty body tissue

Benelux European customs union encompassing Belgium, the Netherlands and

Luxembourg

buck adult male fallow deer

bull uncastrated adult male bovine

calf juvenile red deer

calpain calcium activated muscle protease

carcass body of a slaughtered animal after exsanguination and evisceration

castrate animal with gonads removed, usually male

cathepsins lysomal bound protease

caudal position situated toward animal‟s tail region

cow adult female bovine

cranial position situated toward animal‟s head region

denver to remove the silver skin of a primal meat cut

doe adult female fallow deer

epimysium thick connective tissue sheath surrounding muscles

fawn juvenile fallow deer

havier deerwith gonads removed, usually male

heifer young cow

hind adult female red deer

in vivo in live animal

kiloton 1000 tonnes

lactation period of suckling by fawns and calves

myofibril long, rod-like, contractile organelle of muscle cells made of

sarcomeres

myofilament protein filaments of sarcomere, composed of actin and myosin

protease proteolytic enzyme digests peptide bonds of protein and peptides

rigor muscle depleted of ATP, muscle stiffens

rut deer mating season

sarcolemma transparent membrane covering muscle fibres

sarcomere repeating contractile unit of the myofibril

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stag adult male red deer

steer young castrated male bovine

tonne 1000kg

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List of Specific Names

Common Name Specific Name

Blackbuck Antelope Antilope cervicapra

Buffalo Bubalus bubalus

Camel Camelus dromedarious

Caribou Rangifer tarandus L.

Chamois Rupicapra pyrenaica parva

Chital deer Axis axis

Domestic cattle Bos taurus/indicus

Domestic goats Formosa formosa

Domestic pigs Sus scrofa domestica

Domestic sheep Ovis ovis spp.

Elk / Wapiti Cervus elaphus canadensis

Elk Cervus elaphus nelsoni

Fallow deer Dama dama

Feral goats Capra hircus

Feral sheep Ovis aries

Gemsbok Oryx gazella

Hog deer Axis porcinus

Impala Aepyceros melampus

Kangaroo Macropus spp.

Kudu Tragelaphus strepsiceros

Mesopotamian fallow deer Dama dama mesopotamica

Moose Alces alces

Mufflon Ovies aries orientalis

Mule deer Odocoileus hemionus

Muskoxen Ovibos moschatus

Ostrich Struthio camelus domesticus/australis

Pronghorn Antilocarpa americana

Rabbit Oryctolagus cuniculus

Red deer Cervus elaphus

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Common Name Specific Name

Reedbuck Redunca fulvorufula

Reindeer / Caribou Cervus rangifer

Reindeer Rangifer tarandus tarandus

Roe deer Capreolus capreolus

Rusa deer Cervus timorensis

Sambar deer Cervus unicolor

Sika deer Cervus nippon

Springbok Antidorcas marsupialis

Tahr Hermitragus jemlaicus

White tailed deer Odocoileus virginianus

Wild Boar Sus Scrofa

Wildebeest Connochaetus spp.

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Publications Arising from this Study

Hutchison, C.L., Mulley, R.C., Flesch, J.S., and Wiklund, E. 2012. „Effect of

concentrate feeding on instrumental meat quality and sensory characteristics

of fallow deer venison‟. Meat Science, 90, pp. 801-806.

Hutchison, C.L., Mulley, R.C., Flesch, J.S., and Wiklund, E. 2010. „Consumer

evaluation of venison sensory quality: Effects of sex, body condition score

and carcase suspension method‟. Meat Science, 86, pp. 311-316.

Hutchison, C.L., Flesch, J.S. and Mulley, R.C. 2006. „The Effect of Pelvic

Suspension on the Biochemical and Sensory Quality of Venison from Red

deer (Cervus elaphus) and Fallow deer (Dama dama)’.In: Proceedings of the

6th International Deer Biology Congress, Prague, Czechoslovakia, August 7-

11, pp. 212-215.

Hutchison, C.L., Flesch, J.S., Mulley, R.C. and Wiklund, E. 2006. „Studies of the

relationship between body condition score and venison quality characteristics

in red and fallow deer‟. In: Proceedings of the IV World Deer Congress,

Melbourne, Australia, April 20-22, pp. 86-88

Mulley, R.C., Hutchison, C.L., Flesch, J.S., Wiklund, E, and Nicetic, O. 2006.

Venison Quality. The relationship of body condition score with consumer

perception. Rural Industries Research and Development Corporation,

Publication No 06/043, CanPrint, ACT, ISBN 1741513065.

Wiklund, E., Hutchison, C., Flesch, J., Mulley, R. and Litteljohn, R.P. 2005. „Colour

stability and water-holding capacity of M.longissimus and carcass

characteristics in fallow deer (Dama dama) grazed on natural pasture or fed

barley‟. Rangifer, 25 (2): pp. 97-105.

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Hutchison C.L., Mulley, R.C., Flesch, J.S & Nicetic, O. 2004. „The relationship

between body condition score and venison quality, in farmed, entire and

castrated fallow deer bucks (Dama dama)‟. In: Proceedings of the Australian

Society of Animal Production Conference, Melbourne, July, pp. 321-327.

Sims, K.L., Wiklund, E., Hutchison, C.L., Mulley, R.C. and Littlejohn R.P. 2004.

„Effects of Pelvic Suspension on the Tenderness of Meat from Fallow Deer

(Dama dama)‟. In: Proceedings of the 50th International Congress of Meat

Science and Technology, Helsinki, Finland, pp.12-13.

Wiklund, E., Mulley, R.C., Hutchison, C.L. and Littlejohn, R.P. 2004. „Effect of

Carcass Suspension Method on Water Holding Capacity of Fallow Deer

(Dama dama) and Lamb Meat (M.Longissimus)’. In: Proceedings of the 50th

International Congress of Meat Science and Technology, Helsinki, Finland,

pp. 18-20.

Hutchison, C.L., Mulley, R.C. and Nicetic, O. 2002. „The relationship of body

condition score and venison quality characteristics in fallow deer (Dama

dama)‟. In: Proceedings of the 5th International Congress on the Biology of

Deer, Quebec City, Quebec, Canada, pp. 239-243.

xxiv

Presentations Arising from this Study

Hutchison, C.L. 2008. The Relationship of Body Condition Score and Carcass

Composition to Consumer Perception of Venison Quality. Innovations

Conference, June 2-4, University of Western Sydney.

Hutchison, C.L. 2007. Consumer Perception of Venison Quality. Innovations


Hutchison, C.L., Flesch, J.S. and Mulley, R.C. 2006. The Effect of Pelvic Suspension

on the Biochemical and Sensory Quality of Venison from Red deer (Cervus

elaphus) and Fallow deer (Dama dama). 6th International Deer Biology

Congress, Prague, Czechoslovakia, August 7-11.

Hutchison, C.L. 2006. The Relationship of Body Condition Score and Carcass

Composition to Consumer Perception of Venison Quality. Innovations


Hutchison C.L., Mulley, R.C., Flesch, J.S & Nicetic, O. 2004. The relationship

between body condition score and venison quality, in farmed, entire and

castrated fallow deer bucks (Dama dama). Australian Society of Animal

Production Conference, Invited Speaker, Melbourne, July.

Hutchison, C.L. 2005. Consumer venison quality characteristics in fallow deer

(Dama dama). Innovations Conference, June 3-7, University of Western

Sydney. 2005 conference award winner.

Hutchison, C.L. 2004. Venison quality characteristics in commercial grade fallow

deer (Dama dama). Innovations Conference, June 4-8, University of Western

Sydney.

xxv

Hutchison C. 2004. Relationship of Body Condition Score and Carcass Composition

to Consumer Perception of Venison Quality, Deer Industry Association of

Australia, Biennial Conference, April, Mt Gambier, SA (Invited presenter).

Sims, K.L, Mulley, R.C., Hutchison, C.L. & Wiklund, E. 2004. Post-Slaughter

Management of Fallow deer (Dama dama). Effect of Pelvic Suspension

Method on Meat tenderness. Deer Industry Association of Australia, Biennial

Conference, April, Mt Gambier, SA (Invited presenter).

Hutchison C.L., Mulley, R.C. and Nicetic, O. 2002. The relationship of body

condition score and venison quality characteristics in fallow deer (Dama

dama). 5th Int. Deer Biology Conference, Quebec City, Canada. July.

Hutchison C.L. 2001. Relationship of body condition score to venison quality. Deer

Industry Association of Australia, Biennial Conference, 7-9th September

2001, Canberra, ACT, (Invited presenter).

xxvi

Abstract

The supply of venison to the Australian domestic market is undermined by

inconsistent quality, lack of consistent supply, poor presentation and lack of product

knowledge by marketers and at point of sale. The aim of this work is to improve

quality assurance of venison produced by the Australian deer industry. This study

investigated links between live animal body condition along with pre- and post-

slaughter management with subsequent meat quality and consumer acceptance. A

study of this type has never before been conducted on venison.

Data for venison from fallow deer (Dama dama) castrates (n=18), bucks (n=31) and

does (n=24) as well as red deer (Cervus elaphus) stags (n=26) were analysed. The

study included pre-slaughter management of deer such as the effect of animal body

condition score, sex, supplementary feeding and pre-slaughter stress. A number of

post-slaughter treatments were also examined, including the effect of carcass ageing

and hanging method. Pre-slaughter Body Condition Score (BCS), the feeding

regimen for finishing deer prior to slaughter, and post-slaughter meat quality

attributes including pH, moisture content, fat content, fat distribution, shear force,

and Lab* colour measurement were the factors analysed along with consumer

sensory evaluation.

As body condition score increased so did levels of intramuscular fat, BCS 2-3

(p<0.001) and BCS 3-4 (p<0.01). Instrumental tenderness of venison also increased

as BCS increased, significantly so when BCS 4 animals were included in the study:

fallow does (p<0.01) and red stags (p<0.05). Even though venison from BCS 4

animals was more tender, BCS 2 and 3 animals provided venison of acceptable

tenderness, with most shear force values below 5.0kg and all well below 6.0 kg.

These data for tenderness are of importance to venison producers when determining

the condition of animals for slaughter, and producing for particular markets.

Freeze-thaw/purge losses were significantly higher in fallow deer bucks of BCS 3

when compared with BCS 2 (p<0.001). Bucks of BCS 3 had higher moisture content,

xxvii

though this was not significant. Significantly higher losses may be a result of a

number of factors including moisture content and fat percentages.

Meat colour measurements showed a decrease of redness as BCS increased. The

lower redness values were only significant for BCS 4 animals, being red deer stags

(p<0.01) and fallow deer does (p<0.05). This decrease in redness may be related to

fat deposition within the muscle in higher BCS animals. Fallow deer castrates of

BCS 2 and 3 had lower redness (p<0.05) and yellowness (p<0.05) than fallow deer

bucks of the same BCS, which may be attributable to hormonal status, muscle

activity and fat accretion.

Venison from fallow deer does produced the lowest shear force values (p<0.001),

regardless of BCS and animal age. These data suggest that older females culled for

poor reproductive performance are still suitable to slaughter and produce quality

venison. There were no significant differences in instrumental meat quality between

castrated male fallow deer and bucks.

Concentrate feeding of fallow deer does increased BCS (p<0.001). The concentrate-

fed deer had significantly higher live weights (p<0.001), carcass weights (p<0.01),

fat deposition and dressing percentages (p<0.001). Pasture-fed fallow deer venison

held its redness for a longer period than concentrate-fed venison (p<0.01), which is a

positive for pasture based management systems. Concentrate-fed animals had

significantly more tender meat than the pasture-fed group (p<0.05) which is probably

related to the increase of BCS and IMF.

In this study it was demonstrated that prolonged pre-slaughter handling in connection

with slaughter at an export abattoir significantly increased venison pH values

(p<0.05), compared with smaller purpose built slaughter systems. Stress before

slaughter can induce muscle glycogen depletion so meat pH stays above 6.0 and dark

firm dry meat (DFD) occurs.

Meat ageing is a technique employed by the meat industry to enhance tenderness of

product over various storage times. Dry ageing venison from fallow deer bucks and

castrates for between 5 and 10 days in this study had no significant effect on an

xxviii

already tender venison product. There was a general tendency for the meat aged for

10 days to be more tender, however, these differences were not statistically

significant.

The technique of hanging carcasses by pelvic suspension instead of by the Achilles

tendon resulted in more tender meat for fallow deer bucks (p<0.001), fallow deer

does (p<0.01) and red deer stags (p<0.001).

In this study, experiments using a consumer panel were conducted. Panellists

detected a gradual increase in tenderness of venison as BCS increased from 2 to 4,

and preferred venison from animals with a BCS of either 3 or 4, compared with BCS

2. Male panellists detected an increased darkening of the cooked meat as BCS

increased (p<0.01) compared with female panellists, however, this did not affect

overall liking or preference. Animals ranging in BCS from 2 to 4 can be slaughtered

without apparent effect on consumer preference, which allows for flexibility in the

supply chain. The data indicate no overall difference in liking for BCS 2-3 animals,

hung by the Achilles tendon, whether bucks or does (p>0.05). This is also important

given that most fallow deer presented for slaughter fall into this BCS range.

BCS was increased by grain feeding young animals to achieve BCS 4, which was not

achievable by pasture feeding alone. Consumer panels reported a significantly

stronger flavour in the venison from animals fed grain prior to slaughter (p<0.01),

particularly in animals that remained at BCS 3. Male panellists were particularly able

to detect a difference according to the number of days the animals were fed

concentrate feed, with longer feeding periods resulting in stronger flavours

(p<0.001). This result did not however affect overall liking or preference. However,

the stronger flavour in venison from grain-fed animals was not detected in animals of

BCS 4 in this study, possibly as a result of the higher intramuscular fat content

affecting the flavour strength of the muscle. As there were no significant differences

in other quality parameters between BCS 2, 3 and 4 animals, or between animals fed

grain or pasture, there would appear to be no justification for fallow deer farmers to

finish animals on grain prior to slaughter to achieve higher BCS.

xxix

Meat from fallow deer does was generally perceived as more tender than bucks

(p<0.001), even at older ages, and had a high overall liking rating by consumers even

though the meat was darker (p<0.001) and had a stronger flavour (p<0.01). The

middle aged group of panellists detected a stronger flavour in does (p<0.01), possibly

due to the animals being older, and this age group of panellists contained a higher

percentage of current venison consumers than the younger or older age groupings.

The group with previous game meat eating experience also detected a stronger

flavour in the venison from does (p<0.001). These results did not affect overall

liking.

The consumers clearly distinguished their overall liking for venison derived from

carcasses treated with pelvic suspension post-slaughter compared with Achilles

tendon suspension (p<0.001). This preference was demonstrated by the important

quality characteristics of tenderness and juiciness (p<0.001) which both increased in

venison as an effect of this technique. This finding is also consistent with the

instrumental data collected in this study, and indicates that the technique of pelvic

suspension should be adopted by the deer industry to produce venison for which

consumers have an increased preference.

The pH values measured in venison in the present study were in the range to

guarantee optimal tenderness which was supported by the consumer scores for

tenderness in venison, all averaging values of 8 or above on the scale from 0 (very

tough) to 11 (very tender). This suggested that all venison evaluated, regardless of

species, sex, age, BSC or carcass hanging method, generally was judged to be very

tender.

The hypothesis that changes in BCS would dramatically affect eating quality and

consumer preference has not been proven in these experiments for either species of

deer. The meat quality parameters measured, however, showed differences across the

BCS range 2 to 4, in increases in tenderness, less redness and higher levels of IMF,

particularly in red deer and fallow deer does with BCS 4 compared with BCS 2. This

difference is confirmed by the slight differentiation between BCS 2 and BCS 4 by

taste panellists, but with no negative implications for overall liking. It is apparent

from data for both red and fallow deer that there was a trend for greater overall liking

xxx

of venison from animals with BCS 3 and 4, compared with BCS 2, but this trend was

not significant. It may be necessary to slaughter larger numbers of animals to prove

beyond doubt that this trend is measurably significant.

The need to adopt the post-slaughter practice of pelvic suspension of deer carcasses

of all ages, sexes and body condition scores is unequivocal if enhanced tenderness of

venison is desirable. The sensory panels in this study validated the objective tests

that indicated increased tenderness and juiciness of venison from carcasses subjected

to pelvic suspension compared with carcasses hung by the Achilles tendon.

Flavour is a key quality attribute for consumers and in this study flavour was shown

to increase as animals aged and if they were fed grain prior to slaughter. The

detection by male panellists of stronger flavours in venison from deer fed grain prior

to slaughter was more surprising and this finding could be used by the deer industry

to satisfy market preference for stronger flavours, or could be a warning to restrict

the feeding of grain prior to slaughter if stronger flavours are not desirable.

Comparative evaluation of venison from bucks and does for „overall liking‟ indicated

consumer preference for venison from does. This is useful information for the deer

industry, especially with reference to slaughter of fallow deer, because fallow deer

bucks are very aggressive toward each other during the breeding season and at this

time of year, carcasses can be bruised and dehydrated. Venison quality can remain

acceptably high by slaughtering cull female stock during the breeding season.

Overall, this study has shown that venison is a high quality product. Sensory

evaluation showed the product to be strongly appreciated by men and women

between the ages of 25 and 55, and differences in „overall liking‟ between red and

fallow deer venison were not detected in this study. Consumer behaviour is shaped

by the availability of product to meet their needs. The decision to purchase food

products is generally influenced by perception of quality in terms of safety, sensory

aspects, nutrition and health (Troy and Kerry 2010). This study confirms that

Australian venison has the potential to meet all of the characteristics desired by

consumers.

Chapter One

1

Chapter One

General introduction

Red versus fallow deer

Chapter One

General introduction 1

1.1: Background 2

1.2: Study aim 4

1.3: Experimental approach 4

1.4: Structure of the thesis 5

Chapter One

2

1.1: Background Consumer perception of venison is a critical issue for the Australian deer industry.

Inconsistency of Australian venison is currently a major difficulty in establishing

repeat purchasing by consumers and has resulted in Australian producers being

largely dependent on a volatile export market (Cox et al 2005). Supply of venison to

the Australian domestic market has been undermined by inconsistent quality, lack of

consistent supply, poor presentation and lack of product knowledge by marketers and

at point of sale. Potential local consumers of Australian venison appear to lack

confidence in the industry‟s ability to supply quality venison, particularly in the food

service industry where much of the venison sold is imported from New Zealand

(Tuckwell & Tume 2000).

Consumer behaviour is shaped by personal needs and the availability of product to

meet those needs. Consumers purchase a product when their perception of that

product is positive and this generally relates to quality in terms of safety, sensory

aspects, nutrition and health (Troy and Kerry 2010). Australian venison and venison

in general has the potential to satisfy these consumer desires but has to date, failed to

do so, largely as a result of quality issues.

The Australian venison industry must move towards the same goal for consumer

focused supply systems as the beef (Thompson 2002) and sheep meat (Hopkins

2011) industries have done. A quality assurance (QA) system which addresses both

live animal and carcass processing aspects, both on and off farm, can lead the

industry into a more successful consumer focus with the ability to supply specified

products to markets. This system may facilitate consumer acceptance of venison and

provide consistent quality for repeat purchase. The deer industry must deliver

venison of consistent quality at a reasonable price to promote venison as a healthy,

premium source of red meat.

Consumer perception of venison is a critical issue for the Australian deer industry,

which is currently experiencing an extended slump (Cox et al 2006). Scientific

contributions may form the basis for the ability of the industry to improve

Chapter One

3

consistency and quality of their product as identified by the Rural Industries

Research and Development Corporation (RIRDC) (McRae et al 2006).

The issues of inconsistent quality are of major concern for the industry and need to

be addressed in order for the industry to survive and rebuild. The questions remain;

how does a producer determine when animals are ready for slaughter in order to

produce optimal venison quality? What techniques can be employed pre- and post-

slaughter in order to reliably optimise meat quality?

Research was conducted by Flesch (2001) to provide producers and processors with

a common language for assessing animal body condition and determining suitability

for slaughter. This research resulted in the production of body condition scoring

(BCS) charts for fallow (Tuckwell et al 2000a) and red deer (Tuckwell et al 2000b).

These BCS charts gave Australian venison producers and processors a common

descriptive, assessment language for production and supply of suitable slaughter

stock. The obvious next step was to identify links between BCS and instrumental and

sensory mat quality and determine whether or not a premium live carcass produces

premium quality meat for the consumer. The RIRDC provided funding for this

project to establish links between BCS and meat quality. During this study

examination of pre- and post-slaughter management techniques such as feeding

regime and post-slaughter hanging method, and their effect on venison quality was

also explored. Research of this type had not been previously undertaken on fallow

deer, with some related research conducted on red deer in New Zealand. The links

between instrumental measures of quality and consumer acceptance have not been

previously studied for fallow and red deer venison.

The relationship of BCS along with pre- and post-slaughter management, to

instrumental measurements of deer venison quality and sensory evaluation by

consumers, may have important implications for all sections of the value chain,

especially in smaller industries such as the deer industry where it is critical that

product potential is maximised. Payment to producers based on consumer

satisfaction has the potential to initiate industry change (Polkinghorne and Thompson

2010).

Chapter One

4

Meat quality attributes such as tenderness, juiciness and flavour are not able to be

predicted by the appearance of the live animal or the meat. However, by establishing

links between live animal body condition score (BCS) and carcass fatness (Flesch

2001) with meat quality, predictions may be possible. This will assist producers

when determining the optimal condition of animals for slaughter. Links between live

deer assessment using the BCS system, and the resultant meat quality attributes and

acceptance by consumers has not been previously studied.

It is anticipated that scientific contributions, such as those outlined in this study will

assist the venison industry to improve consistency and quality of product.

1.2: Study aim

The aim of this work was to clearly establish the impact of a number of pre-slaughter

and post-slaughter production and processing techniques on instrumental and sensory

meat quality for venison from red and fallow deer.

The objectives of this study were to determine the effect of the following variables

on instrumental and sensory measures of venison quality as follows:

Body condition score (BCS)

Sex of the animal

Red and fallow deer species

Feeding regimes

Muscle ageing time

Post slaughter hanging technique.

1.3: Experimental approach

The study design followed a systems approach to venison quality; from on farm

growth and development, immediate post-slaughter management, optimum food

preparation through to consumer appraisal and perception. Experimental work was

Chapter One

5

carried out on selected slaughter age, red and fallow deer of body condition scores 2,

3 and 4 (lean, prime and fat) (Tuckwell et al 2000a;b). The research defines carcass

composition of the various scores. The study focuses on pre-slaughter treatments,

post-slaughter handling and meat quality assessment to determine parameters relative

to the production of optimal eating quality venison. In addition to eating quality and

consumer acceptance, venison from deer raised on pasture vs. supplementary feeding

was evaluated. This work uses body condition score as a critical parameter. Sensory

analysis was employed to quantify consumer expectation and acceptance of venison

of the three condition scores undergoing various treatments. The vision to link

carcass production with eating quality has long term implications for acceptance of

venison as a favoured consumer selection, just as Meat Standards Australia (MSA) is

achieving for the beef industry.

Definition of the relationship of BCS, along with pre- and post- slaughter treatments

with cooking and eating quality will increase opportunities for target marketing,

which should increase farm profitability and consumer satisfaction if product

consistency is enhanced. The pre- and post-slaughter techniques employed in this

study tested the effect of pelvic suspension (tender stretching) of carcasses for

product enhancement, evaluated ageing of venison, and looked at the effect of

supplementary feeding of deer pre-slaughter compared with pasture-fed deer, on

consumer sensory perception of meat quality attributes.

1.4: Structure of the thesis

This thesis is structured with a general introduction in Chapter 1, a literature review

in Chapter 2, general materials and methods in Chapter 3, four experimental chapters

from Chapter 4 to 7 and final conclusions in Chapter 8.

Chapter 4 establishes the relationship between body condition score and instrumental

measures of venison quality for both fallow and red deer.

Chapter One

6

Chapter 5 examines the effect of feeding concentrate feeds on the instrumental meat

quality of venison from fallow deer does.

Chapter 6 examines a number of pre- and post-slaughter management techniques,

including ageing time and carcass suspension methods on the instrumental quality of

fallow and red deer venison.

Chapter 7 encompasses all of the areas examined in Chapters 4 to 6 and presents

samples from these earlier experiments to consumer panellists for evaluation.

Chapter 8 brings together the main findings of the study and incorporates some

recommendations to industry.

Chapter Two

7

Chapter Two

Literature review

Venison sample collection

Chapter 2 Literature review 7

2.1: Venison production 8 2.1.1: History of deer as a meat species 8 2.1.2: Deer in Australia 8 2.1.3: Deer farming and venison production 9 2.1.4: Venison in the human diet 14 2.1.5: Current markets 18 2.1.6: Venison specifications 26

2.2: Measures of meat quality 28 2.2.1: Meat from muscle 28 2.2.2: Factors affecting meat quality 32 2.2.3: Consumer perception 49 2.2.4: Beef and sheep meat quality improvement schemes 51 2.2.5: Estimations of body condition 57

2.3: Industry issues 62 2.3.1: Background 62 2.3.2: Current venison issues 67 2.3.3: Strategic industry alliances 73

Chapter Two

8

2.1: Venison production

2.1.1: History of deer as a meat species

Deer are ruminants that constitute the family Cervidae of the order Artiodactyla and

sub-order Ruminantia. The Cervidae family consists of seventeen genera, forty

species, and over 190 different sub-species (Whitehead 1972).

It is believed that deer appeared early in the Oligocene epoch in Asia approximately

38 million years ago, with the dating of remains of fallow deer going back to the

second interglacial period 250,000 years ago (Chapman 1993). The intensive

husbandry of deer in farming environments, however, is relatively new to modern

agriculture, although archaeological records suggest breeding and utilisation by man

from 9000 BC (Reinken 1997). Most of the deer on farms today are believed to be no

more than forty generations removed from their wild descendants. Farmed deer still

exhibit some aspects of wild behaviour, with their ancestry still having an effect on

their diurnal and annual patterns of feed intake, growth and reproduction in managed

pastoral environments (Flesch 2001). Deer have not been selectively bred by man for

at least 5000 years and as such remain one of a few species to have been recently

domesticated (Fletcher 1998) for food production. Farmed deer have undergone little

genetic selection for improved domesticity, though are habituated to the farm

environment. This is in stark contrast to domesticated ungulates such as cattle, sheep

and goats, which have undergone extensive physiological, morphological and

behavioural changes as a result of thousands of years of selection for domesticity

(Flesch 2001).

2.1.2: Deer in Australia

Due to the lack of land bridges, native deer did not exist in Australia when cervids

spread throughout the world 15,000 to 30,000 years ago (Hansen 2004). Deer were

introduced into Australia as part of an acclimatisation program in the early 19th

Century, with the aim of “a more equitable distribution of the world‟s useful and

beautiful species” (Bentley 1978). This government program oversaw the

Chapter Two

9

introduction of several exotic species of animals and birds for use and hunting by the

British colonists. The first reported imports were of chital deer from India in 1800 by

Dr John Harris to his farm in the area which is now known as Chinatown in Sydney.

By 1809 his herd numbered 400 head (Hansen 2004). Approximately 20 deer species

were released from the mid 1800s up until 1900 by acclimatisation societies, hunting

clubs and individuals (Bentley 1978). Of these, only six remain after successfully

establishing wild populations, being red, fallow, rusa, chital, sambar and hog deer

(Moriarty 2004). These animals formed wild populations, and individuals from these

populations eventually formed the basis of Australian deer farming. Initial supply of

animals for farming came from capturing animals from wild populations, mainly

fallow deer in New South Wales, red deer in Queensland and rusa deer from the

Royal National Park near Sydney (Falepau 1999; Hansen 2004; Joubert 2004). Red

and fallow deer comprise most of the national herd of farmed deer with farms located

in NSW and Victoria. Rusa deer are farmed primarily in Queensland. Tasmania is

populated only with fallow deer, both in the wild and on farms (Falepau 1999).

2.1.3: Deer farming and venison production

Venison is traditionally defined as the meat from any furred game animal including

deer, rabbit and hare but is now more commonly used to refer to the meat of any

species of deer, whether hunted or farmed. Archaeological evidence shows that man

has been eating venison for many more centuries than beef or lamb and it has

constituted the base of meat diets for Europeans for between 5000 and 50000 years

(Fletcher 2001). The need for quality protein, fat, ease of domestication, draft

animals and fibre led to domestication of cattle and sheep 8000 years ago and for

man to hunt a variety of wild animals for food, clothing and fuel. Man no longer

requires a diet high in fat and lean meat meets consumer demands for healthier

lifestyles. Venison from deer and a number of other game meats can potentially meet

the demand for leaner and healthier meat sources (Wiklund et al 2010).

While sheep and cattle were being domesticated deer relied on natural selection and

thus populations have not had much human influence. The first deer farm was

established in Scotland in 1971 to farm red deer and was soon followed by a fallow

Chapter Two

10

deer farm established in Germany in 1973 (Reinken 1998). Red and fallow deer were

selected as a production species in Europe due to their longevity, disease resistance,

hardiness in winter, ease of calving and carcass and meat quality. Today, apart from

fallow and red deer, European game farms produce sika deer, roe deer, mouflon

(wild sheep) and wild boar, with often several species farmed together, particularly

in areas of culinary demand or where there are trophy hunting areas and tourism

(Audenaerde 1998). The challenge for deer farmers is to domesticate and breed for

temperament, leanness and growth in order to meet market requirements.

Deer farming, hunting, venison production and consumption has been firmly

established in Europe for many years (Piasentier et al 2005). The European Union

(EU) plays a major role in world production of farmed venison. Venison is produced

locally in several European countries, with centres for production, particularly for

fallow deer, being Austria, Germany, Italy, Sweden and Switzerland. Deer farming

has also been established in the Czech Republic, Portugal, Norway, Hungary,

Poland, Slovakia and Spain. Red deer are principally farmed in Great Britain.

However, European consumption far exceeds the ability of the EU to supply

sufficient quantities of venison (Audenaerde 1998). This surplus demand is catered

for primarily by imports of farmed venison from New Zealand, and to a much lesser

extent Australia, and some inputs from wild product harvested in Scotland and

central Europe. Countries such as Germany and the Scandinavian countries have a

culture of consuming venison. Countries, such as Australia where that culture is

missing, are often forced to export the venison that is produced. Europe produces for

its own consumption, while the New Zealand and Australian venison industries

depend on exports. There has been an increase in interest in venison by the EU due to

the recognition that venison is a healthy product. It is estimated that there are over

10,000 deer farmers in the EU producing over 7,000 tonnes of venison, and numbers

continue to rise (AACMI 1998; Audenaerde 1998). In 2002, estimates of the

European farmed red and fallow deer population stood at 410,000 and Scandinavian

reindeer at 90,000, while the total wild population was estimated at over 1 million

red deer, 5.5 million roe deer, 500,000 moose, 125,000 fallow deer and 50,000

reindeer (Fletcher 2004). Consequently the farmed venison sector in Europe is small

in relation to meat supplied from the wild venison sector, and there continues to be a

large market for trophy hunting, which is vital to the success of the European deer

Chapter Two

11

industry (Fletcher 2004). In 2004, farm sizes were very small with a predominance of

hobby farmers. Norway had 51 farms with a population of 650 deer, Benelux had

1,500 farms with 2,400 deer, and Switzerland, 485 farms carrying 8,389 deer. The

Czech Republic had approximately 200 farms with estimates of between 5,000 and

8,000 deer; Denmark had 142 farms with 20,000 deer and Poland 60 farms carrying a

total of 4,900 deer. Most farms carry only red and fallow deer, with Denmark also

carrying 200 sika deer (Fletcher 2004). More recent statistics on European farmed

deer holdings and meat processing quantities are difficult to obtain. In 2010, it was

reported that deer farming in the Netherlands was in decline, Latvia had several

holdings with a maximum of 60 deer per holding, France had 50 deer farms and 200-

330 deer parks, Switzerland had 600 deer farms, Sweden farmed 20,000 fallow deer

and 67,000 red deer, and there were large numbers of nomadic indigenous

communities farming or herding semi domesticated reindeer in Northern Europe. The

Czech Republic had 350 deer farms, Slovakia, 59 farms, while Lithuania had 152

deer farms. Germany had 6,000 small farms, mostly in Bavaria, with 70% having

fallow deer, and Austria had 1,600 deer farms but animal numbers were not reported

(FEDFA 2010). Recent estimates (FEDFA 2010) report national deer herd numbers

in the United Kingdom at 36,000, an increase from 2004 when there were 311 farms

carrying 32,500 deer (Fletcher 2004), with the majority being red deer, a number that

has been relatively stable and exhibiting only minor fluctuations since 1995

(Hoffman and Wiklund 2006).

Sweden, Norway, Finland and New Zealand lead the world in commercial venison

production, both in terms of quality and quantity. In the case of the Scandinavian

countries the venison comes from semi domesticated reindeer, and with New

Zealand, principally from farmed red deer (Wiklund 1996).

New Zealand has the world‟s largest and most advanced deer farming industry

(Pearse and Fung 2008). The first deer were brought to New Zealand from England

and Scotland for hunting in the mid to late 19th century. They were released and the

environment proved ideal: feral populations grew uncontrolled. The New Zealand

deer industry was established as a result of the capture of feral deer that were seen as

a pest species in New Zealand in the 1960s. The first breeding herd was established

in 1970 (Quinn-Walsh 2010) and has, over forty years, developed into a significant

Chapter Two

12

export industry (Asher et al 2011; Hoffman and Wiklund 2006). Since the

establishment of a commercial deer industry in New Zealand, producers have

imported red deer genetics from Europe, and elk from Canada and the USA, to

improve both velvet antler and venison production (Barry and Wilson 1984). In

2005, the New Zealand farmed deer herd was estimated at 1.7 million on 4,500

farms, the majority (85%) being red deer and the balance mostly elk or wapiti and a

few fallow deer. Of these, 680,000 head were slaughtered annually for venison

(Hoffman and Wiklund 2006), up from 83,000 head slaughtered in 1988 and 258,000

in 1992 (Drew and Stevenson 1992; Pearse and Fung 2008). In 2006, deer numbers

fell to 1.6 million and have continued to decline, with figures for 2007 being 1.4

million and current figures estimating the population at 1.12 million (MAF 2011) on

3,000 farms (Stewart 2011). The decline is attributed to producers with mixed

species farms reducing their deer numbers. A rebuilding of populations has

commenced and is expected to slowly continue (MAF 2011). The majority of deer in

New Zealand are farmed for venison and co-products, with the remainder bred for

velvet production (Pearse and Fung 2008). Ninety percent of the products, being

venison, velvet antler and co-products, were exported (Hoffman and Wiklund 2006,

MAF 2011). New Zealand currently supplies over 50% of the world‟s internationally

traded venison (Asher et al 2011). Revenue from exports in 2008/2009 was $NZ320

million, with 18,700 tonnes exported, of which 68% went to Germany (Quinn-Walsh

2010).

Deer farming is a mainstream industry in New Zealand and is the largest producer of

venison and velvet antler in the Asia Pacific region. The New Zealand deer industry

is ten times larger and produces twenty times more venison per annum than Australia

(AACMI 1994). The New Zealand herd is principally made up of red deer compared

with Australia, where the percentage of fallow deer and other species is higher.

Other countries, such as Malaysia, Mauritius, Reunion Island and New Caledonia,

produce the majority of the world‟s rusa deer, both farmed and wild (Hoffman and

Wiklund 2006; Dahlan 2009).

Commercial deer farming in Australia did not begin until the 1970s. The first

commercial deer farm was established in Victoria in 1971, with rusa deer legally

Chapter Two

13

captured from wild populations in the Royal National Park in Sydney (Moriarty

2004). The industry expanded rapidly until the late 1980s (McRae et al 2006) after

the publication by Anderson (1978), Gold on Four Feet, sparked a great deal of

interest in deer farming (Hansen 2004). The Australian Deer Breeders‟ Federation

was formed in 1979 and evolved into the current Deer Industry Association of

Australia Ltd in 1995 (RIRDC 2007). The species farmed commercially in Australia

are red deer, which comprises over 50% of all commercial production for venison

and velvet antler, fallow deer (both European fallow deer (Dama dama) and hybrids

of Persian or Mesopotamian fallow deer (Dama dama mesopotamica), which

constitute almost the remaining percentage and are grown mainly for venison

production. Other species produced in small numbers in Australia include rusa deer

for venison, wapiti/elk and sika/red hybrids for venison and velvet antler, and to an

even lesser extent, chital deer and sambar deer, both for venison (McKinnon 2011).

In 1999 the Australian herd size was 188,000 (Tuckwell 1999). An approximate

distribution of commercial deer operations by state in 1999 was: New South Wales

and Australian Capital Territory 30%, Victoria 26.5%, South Australia 15.5%,

Queensland 11%, Tasmania 8.5%, and Western Australia 8.5%. Of the 938

commercial farms in Australia with deer, only 212 held more than one species

(Tuckwell 1999). By January 2001, numbers were down to approximately 180,000

deer, farmed by between 600 and 1,000 farmers (RIRDC 2007). Fallow deer

comprised 41% of the herd, red deer 41%, rusa deer 12%, elk 4% and chital deer 2%

(Tuckwell 2001a).

The period between 1999 and 2001 saw the Australian deer industry in its most

profitable and commercially successful period since the establishment of the

industry, however, most factors associated with this success were those over which

the industry had little or no control. In particular, the Australian dollar was devalued,

and there was a lack of confidence in European markets in other, more traditional,

red meats, which increased demand for alternatives such as venison. High prices paid

during this period led to an increase in the number of animals processed with the

implications of that felt in subsequent years by producers and processors who were

later unable to keep up with demand due to the inability to supply adequate stock

numbers, despite demand being relatively low (Tuckwell 2003a).

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14

The national herd is currently estimated at 43,856 deer comprised of red, fallow,

rusa, chital, sambar, elk, hog and sika hybrid deer over 196 farms Australia wide

(McKinnon 2011). Red deer now comprise the majority of the herd at 48%, due their

ability to produce larger quantities of venison and velvet; fallow deer comprise 44%

with the remaining percentage being rusa, elk, sambar, chital, hog deer and other

unspecified species (Shapiro, 2010; McKinnon, 2011). It is believed that the majority

of deer found in Australia are wild, with deer farming for venison and velvet

performed by a small number of producers (Hoffman and Wiklund 2006; RIRDC

2007).

In 2011, of the 196 confirmed deer farms in Australia, the majority are located in

Victoria (35%), South Australia (24%) and New South Wales (12%) (Shapiro 2010),

with a small number located in Tasmania, Western Australia and Queensland

(McKinnon 2011). The Australian deer industry has a small number of large scale

farms and many smaller farms. The ten largest farms have over 1,000 head of deer

and represent 41% of the industry, while the smallest one hundred farms comprise

less than 10% of the total. One Australian producer has 4,500 head of deer, totalling

approximately 10% of the national herd, while 44 producers have less than 20

animals (Shapiro 2010).

2.1.4: Venison in the human diet

Red meat is a primary dietary component for human beings and should form part of a

well balanced and varied diet to be consumed on a daily basis (NHMRC 2003).

During the early period of Australia‟s colonisation, meat was in abundance and

consumption of beef and lamb in the 19th century was estimated at 290kg per capita

annually. By the mid 1940s this had declined to 190 kg per capita and by 1970 to 80

kg, 1990 to 52 kg and in 2008 50 kg per capita (Williams and Droulez 2010) with

only 10.4 kg of that coming from lamb (Fletcher et al 2009; Rees 2010).

Consumption of red meat in Australia has declined, despite increases in production,

however, total meat consumption has not declined, with an increase in the

consumption of white meat such as chicken and pork (Fletcher et al 2009). Based on

epidemiological studies, there is a positive association between saturated fat intake

Chapter Two

15

and obesity with red meat consumption. However, the nutritional benefits of

moderate meat consumption in terms of protein, vitamins and minerals outweigh the

disadvantages of intake of saturated fats (Schonfeldt and Gibson 2008).

There have been substantial changes in carcass composition, in terms of reduction of

fat, both biologically and as a result of trimming and adjustments in cooking methods

to further reduce the possibility of high saturated fat intake. These changes are

reflective of an increase in consumer demand for leaner red meat products and there

is an increase in global demand for high value animal protein (Schonfeldt and Gibson

2008; Stewart 2011). Consumers indicate that the nutritional value of the meat in

their diet is of increasing importance to them, and subsequently, to the meat industry

(De Smet 2011). In 2007, a survey indicated that 89% of red meat consumers

reported buying trimmed meat (5%) or removed some of the fat (84%) prior to

consumption, and over the past 20 years increasing consumer awareness of the

importance of health and the role of saturated fat has influenced consumer demands

and practices (Williams and Droulez 2010).

Deer venison is suited to modern consumer demand for lean red meat of high

nutrient value and low in fat, and is easy to prepare (Hoffman and Wiklund 2006;

Issanchou 1996). Compared with beef and lamb, venison has several advantages,

including a higher percentage of lean meat and more valuable cuts, and less fat and

bone (Hoffman and Wiklund 2006). As a result of the low fat content and favourable

fatty acid ratios, consumption of saturated fats is decreased (Piasentier et al 2005;

Wiklund et al 2010). However, younger consumers tend to consume less red meat

and more pork and chicken due to the perception of red meat not being as healthy as

white meat (Fletcher et al 2009). Women in particular consume less red meat and are

particularly low consumers of game meats such as venison (Hoffman and Wiklund

2006).

A study by Moffat (2005) indicated that consumers felt that venison was unsuitable

for children due to the perceived requirement of cooking only to rare doneness and

would therefore not purchase the meat for family meals. Moffat (2005) also reported

a perception that venison must be served very rare in order to retain its tenderness

characteristics and suggested that research to confirm this would be worthwhile. A

Chapter Two

16

study by Shaw (2000) indicated that venison cooked to medium doneness performs

well in sensory tests. Ironically, the health benefits provided by venison are

particularly suited to women of reproductive age, adolescent girls and growing

children due to the high percentage of quality protein, low fat content and high iron

levels. Venison has less than a quarter of the fat and 35% more protein per 100g of

tissue than beef (Aidoo and Haworth 1995).

When consuming venison or lean chicken, 22% of the energy is derived from the fat

content while beef, lamb and pork has values ranging from 33% to 47%. Venison has

an average total energy content of only 500 kJ per 100g compared to an average of

750 kJ per 100g for lean beef and lamb (Aidoo and Haworth 1995). The cholesterol

content in venison is also on the lowest range found in the majority of meat animals

at 80mg/100g of tissue. Significantly, it supplies almost 40% of the adult RDI of iron

in a 100g portion, while being lower in sodium and higher in copper and zinc than

lamb (Aidoo and Haworth 1995; Daszkiewicz et al 2009; Drew and Seman 1992;

Duranti et al 1994). Since the consumption of meat is unlikely to decline, it makes

sense for consumers to consider selecting venison for optimal nutrition (Radder and

le Roux 2005).

In a South African study (Radder and le Roux 2005) 55% of consumers admitted that

they did not know how to cook venison. Education is critical in relation to the

cooking of venison as there was also a perception that the meat is dry and tough and

is possibly being over cooked, or in some cases, under cooked (Radder and le Roux

2005). To this end the New Zealand deer industry has made an effort to educate new

domestic and international consumers on appropriate ways to cook venison (Barnett

2007). In Germany, the New Zealand venison industry continues to survey and

educate consumers with supermarket demonstrations, resulting in a gradual change in

consumer attitude to venison preparation over the past five years in this important

export market (Griffiths et al 2009). Traditional markets, such as Germany, still

relate the product to traditional preparation methods such as slow cooking with

strongly flavoured condiments, and believe venison to be a seasonal product because

it was traditionally hunted and not farmed. Game seasons in Europe and the United

States were not year round, and venison harvested during these periods (autumn and

winter) was often tough and gamey or livery in flavour due to the breeding season or

Chapter Two

17

rut. As a result, traditional consumers would often utilise moist heat methods of

preparation and strong accompanying flavours in order to compensate for the

tougher, gamier meat harvested during this time (Pearse and Fung 2008). Consumers

need to be shown that farmed venison lends itself to rapid, dry heat methods of

cooking such as grilling and stir frying, and should be done to medium doneness as a

maximum to ensure good eating quality, due to the low fat content and delicate

structure and flavour (Pearse and Fung 2008). The New Zealand venison industry is,

as a result of a productivity strategy, able to supply quality venison all year round,

with marketing strategies aiming to increase consumption in international markets

during what is typically the off season (Pearse and Fung 2008).

There is a paucity of information relating to the target markets for venison. In an

Australian study in 1994, the venison consumer was identified as ranging through all

occupation categories, with a concentration of 80% being professionals (AACMI

1994). Recently, the New Zealand industry identified consumers as being from a

range of age groups within households with high discretionary income, seeking

premium quality food that is healthy, convenient, quick to prepare and available all

year round (DINZ 2011). This has been a move away from the core consumer being

European, between 30 and 60 years old, and affluent with links to traditional

consumption of venison (O‟Connor 2006).

The Australian meat industry has identified a number of areas of fundamental

importance to red meat consumers. Meat should exhibit high organoleptic qualities,

be health enhancing, from ethical production systems, safe for consumers and good

value for money (Pethick et al 2011). Any research should be well integrated within

these parameters in a modern consumer focused industry (Wiklund 2009). Venison

comes from animals that are largely grazed for most of the year which means that

their meat is seen to be produced more ethically and with consideration of animal

welfare when compared with commercial grain produced beef, pork and poultry

(Wiklund 2009). Recent studies have found that while consumers rate red meat

highly in terms of nutrient content, less than 50% of consumers suggest red meat in

Australia is of high quality. The other issue which must be addressed is the consumer

perception of the value of chicken in preference to red meat in the diet, particularly

in relation to obesity and weight loss programs (Pethick et al 2011). As obesity

Chapter Two

18

continues to become a public health issue, the venison industry could benefit with a

product that has lower fat than skinless chicken, high levels of omega-3 fatty acids

and twice the available iron of other red meats (Wiklund 2009). These factors lend

credence to the suggestion that humans are adapted to the consumption of game

meats that have been a staple in the human diet for centuries (Fletcher 2004).

2.1.5: Current markets

Australia is a world renowned producer of red meat, specifically beef and lamb. The

Australian red meat industry has a well established export industry for beef, second

in size only to Brazil, and is also the second largest supplier of lamb, with New

Zealand being the industry leader (Fletcher et al 2009; Hooper 2010a, 2010b).

Australia exports 45% of its lamb production, 79% of mutton and 62% of beef

(Pethick et al 2011). The product is also well established in domestic markets. The

success of these markets, both domestically and internationally, is in large part due to

the ability of the industry to supply a safe, wholesome product of consistent quality

to target markets. Consumer focused research is integral to the success of both

domestic and international markets (Pethick et al 2011). This ability has been a

result, to a considerable extent, of the extensive research that has been conducted by

cooperative research centres (CRC) set up for both the beef cattle and sheep

industries, and adopted by industry segments (Devine 2001).

Venison is placed in a different marketing sector to the more traditional red meats,

beef and lamb. Despite the fact that venison has been consumed for centuries, it is a

relatively new product in terms of farmed meat, and as a result, it has not undergone

the extensive genetic improvements seen in both cattle and sheep (Barnett 2007).

The current market for Australian venison is largely an export market; opportunities

have arisen for export of Asian/Pacific venison, as Australia and New Zealand are

seen as producing a safe product in a clean environment. The majority of venison

exported is as meat cuts, sold chilled or frozen, not whole carcasses, with a small

percentage of live exports to Asia (AACMI 1994). Venison is not, however, well

known or represented in the domestic market. The development and maintenance of

Chapter Two

19

stable domestic and international markets for Australian venison is key to the long

term future of the Australian deer industry.

Since its inception in 1970s the Australian deer industry has relied primarily on

exports to European markets, along with New Zealand, the biggest producer and

exporter of farmed venison. Relatively small volumes are sold to other than the

traditional European markets: smaller markets include the USA (primarily supplied

by New Zealand), Japan, Taiwan and South Korea. The occurrence of the Chernobyl

nuclear disaster, outbreaks of foot and mouth disease (FMD), and bovine spongiform

encephalopathy (BSE or mad cow disease) in Europe and the United Kingdom has

opened up new export markets for safe, clean meat such as Australian and New

Zealand venison (Hoffman and Wiklund 2006), and resulted in record prices for New

Zealand venison (Loza 2003).

Supply of venison to the Australian domestic market has been undermined by

inconsistent quality, lack of consistent supply, poor presentation and lack of product

knowledge by marketers and at point of sale. Supplies are erratic and trade

confidence in year-round supply quality is low. Consumers also lack knowledge of

product attributes and usage. Potential local consumers of Australian venison appear

to lack confidence in the industry‟s ability to supply quality venison, particularly in

the food service industry, where much of the venison sold is imported from New

Zealand (Tuckwell & Tume 2000).

For deer farming to remain viable, activities such as production, processing and

marketing must become larger scale and more efficient to compete with other red

meat options in a competitive market (AACMI 1994). Venison prices to farmers

have fluctuated in recent years and more stable, stronger markets need to be

established. However, the price of venison per kilogram to the consumer in domestic

markets seems not to have been affected by the downturn in returns to producers

(Tuckwell and Tume 2000).

The cost of venison is positioned at the top end of the meat, fish and poultry market.

Venison is still seen as the meat of kings and is positioned as a traditional and luxury

meat. Local consumers may be aware of the product but are reluctant to try it or

Chapter Two

20

cannot source it. Venison has potential to give consumers greater variety in healthy

red meat consumption (Tuckwell and Tume 2000).

The domestic market for venison is small but Australian production remains

inadequate to meet current demand. The shortfall in supply is made up with New

Zealand imports. The main outlets are high-class restaurants, specialty butchers,

game meat stores and gourmet food stores. Constraints to increasing the domestic

market appear to be a lack of knowledge about the product, and how to prepare it.

Markets also prefer fresh to frozen product (Tuckwell and Tume 2000).

Development of the domestic market is critical to the long-term viability of the

Australian deer industry (RIRDC 2007).

In 1994, the Venison market development plan (RIRDC 1994) identified that the

Australian product, compared with New Zealand, was not performing in either

quality or consistency, with few exceptions. The recommendation was for industry to

improve both the quality and consistency of product or carry the consequences

(RIRDC 1994). In May 1998, on farm quality assurance programs commenced and

some farmers began the road to accreditation. The emphasis of the program was on

management of animal health and welfare issues resulting in high quality,

uncontaminated products for human consumption (Tuckwell 1999). These later

evolved into the venison quality assurance program (Tuckwell 2001b) and deer

quality assurance management and analysis (deer QAMA), which provided access to

both written manuals and computer databases to aid producers and processors in

establishing quality assurance systems (Tuckwell 2003a). It is recognised that quality

assurance accreditation is a minimum standard for access to international markets,

rather than simply an opportunity to gain price premiums over non-quality assured

products. As a result of bovine spongiform encephalopathy (BSE), foot and mouth

disease (FMD) and chronic wasting disease (CWD) outbreaks in European and North

American industries, a legacy of consumer concerns regarding the safety of red meat

(Tuckwell 2003a) and quality assurance can put Australian venison in an enviable

position in these markets. Apart from the few producers who have embraced this

program, little seems to have been achieved towards improving quality of venison

supply. AUS-MEAT specifications for all cuts of meat are also an important step in

improving market performance. Overall improvement in product quality and

Chapter Two

21

consistency demanded by consumers can only be achieved by vendors attending to

quality at all stages from livestock procurement to product marketing (RIRDC 2007).

World trade in venison is believed to be about 11,000 tonnes per annum

(Daszkiewicz 2009) with West Germany being the dominant importer of fresh and

frozen product. Swedish people consume on average 2.5 kg of venison annually per

capita, predominately reindeer meat; New Zealand people also consume 2.5 kg

annually, predominately red deer venison, Austrians 0.6kg, predominately fallow

deer venison and the Swiss, 0.5 kg. Germans consume, on average, 0.4 kg per person

per year, French 125g, Spanish 50g, British 40g and Australians 20g (Daszkiewicz et

al 2009; Tuckwell & Tume 2000). As illustrated here, very little venison is consumed

in the Australian market, with the majority of consumption occurring at high-end

food service establishments (McRae et al 2006). Domestic utilisation of Australian

venison was 108.7 tonnes (carcass weight), compared to beef at 763,000 tonnes,

lamb at 208,000 tonnes and mutton at 62,500 tonnes (McRae et al 2006). Despite the

high price of venison, this meat is valued internationally because of its nutrient

composition and fine textural qualities, but remains a traditional market with

consumption higher in locations where venison has been consumed historically for

hundreds of years (Daszkiewicz et al 2009).

Venison processors are attempting to expand their market presence in the United

Kingdom, though lack of supply, insufficient numbers of local producers and falling

New Zealand imports is hampering expansion. There has been a rise in the popularity

of venison in the UK following successful introduction of the product into retail

outlets, and raising consumer awareness of venison as a healthy meat. Sales of

venison have risen from £32 million in 2006 to £43 million in 2010, an increase of

over 34% (Dawson 2011). This is in part attributed to the release of recent research

results linking traditional red meats with cancer and suggesting venison as a healthy

alternative (Polak et al 2008). Due to the shortage of farmed deer venison, the UK is

attempting to satisfy markets with hunted, wild product (Dawson 2011).

The New Zealand industry matured with the development and launch of the

Cervena™ program. Cervena™ venison is distinguished from other venison on the

market by the trademarked assurance that the meat has been naturally produced and

Chapter Two

22

processed in accredited facilities (DINZ 2011).The program relies on industry agreed

quality assurance standards in transport and farm accreditation. The emphasis is on

young animals under three years of age that are free ranging on quality farms varying

in size from 200 to over 2000 acres, grazing on pasture-based systems with no added

hormones or steroids (DINZ 2011). There are also foci on processing, packaging and

freight forwarding as well as point of sale assurances backed by ISO 9002

certification with emphasis on safety and product specification. It is targeted at the

top-end restaurant trade, both domestically and internationally, and has resulted in

good growth for New Zealand venison exports (Anon 2005). Cervena™ venison

claims to be mild yet distinctive in flavour, tender, versatile and available all year

round (DINZ 2011).

The market requirements for an increasing supply of chilled product places demand

on New Zealand farmers to provide 55-65 kg carcasses from red deer. Farmers have

invested in correct genotype and hybrids of wapiti to achieve specifications in

minimum time (Pearse et al 1994; Stewart 2011). The supply of animals has shifted

from post-pubertal two year old animals to pre-pubertal one year old animals, with a

need for animals to achieve slaughter weights earlier. Peak venison schedule

payments to producers is for 8-12 month old animals, principally stags, from August

to November, with live weights ≥ 93 kg in order to achieve 50-65 kg carcass weights.

An optimal minimum carcass weight of 55 kg (Pearse and Fung 2008) has been

established to enable supply to seasonal game markets in Europe (Asher et al 2011).

This has led the NZ deer industry to develop the New Zealand Deer Industry

Productivity Strategy 2009-2014 and to invest money in genetic research to enhance

farm productivity (Quinn-Walsh et al 2010). The aim of this strategy is to increase

carcass weights and introduce a carcass yield module in the performance recording

database DEERSelect (Ward et al 2010). The DEERSelect program determines

breeding values (BV) for terminal and maternal sires, with emphasis on BV for

carcass traits such as growth, yield, eye muscle area and a range of other venison

quality attributes (Bell 2011). Breeding traits of interest for venison production

include weight at weaning, at one year of age, and mature breeding hind weight.

Once quantified in terms of venison quality, they may provide an opportunity for

improved carcass traits to form part of the payment system (Chardon 2009). An

important addition to the productivity strategy is the current Venison Supply Systems

Chapter Two

23

research program, with the specific aim of ensuring that any gains made through

productivity research are not made at the expense of meat quality (Wiklund 2009).

The NZ deer industry dominates the world market for venison with over 400,000

deer slaughtered in 1998, and product directed mainly to Europe and the USA. This

left the Muslim market open to Australia, as halal slaughter practices were not

available in New Zealand (Horsley 2004). In 2005, the NZ deer industry earned

$NZ263 million in export revenue derived from the slaughter of 762,427 deer; with

27,319 tonnes of venison were exported with a value of $NZ213 million, along with

780 tonnes of velvet antler (RIRDC 2007). In 2006, NZ exported 28,000 tonnes of

venison from 770,000 deer slaughtered (O‟Connor 2006). In 2008 they exported

21,800 tonnes with a value of $288 million; in 2009 that figure was 16,900 tonnes

with a value of $293 million. There was a decline in export volume in 2010 to 15,000

tonnes with value of $209 million, which reflected a drop in deer numbers. The total

number of animals slaughtered for 2010/2011 was 394,000 with 16,200 tonnes of

venison exported, at a value of $223 million for both the traditional European game

season and off season, with commodity prices increasing (DINZ 2011). The forecast

for the New Zealand deer industry is for a continued rise in production and exports

(MAF 2011). For the past three years the price paid to producers of New Zealand

venison has been stable and historically high at $NZ 8.03 per kilogram (dressed

weight) (Moffat 2011).

In 1996 it was estimated that 85% of Australian venison was exported to Europe

(50%), with the remainder to the USA and Asia. Prior to 1996, over 85% went to the

Muslim market in Asia (Falepau 1999). By 2006, venison exported from Australia

was estimated at over 90% of production and went predominately to the EU

(particularly Germany), and South-East Asia. Australia has imported in excess of

1000 tonnes per annum of New Zealand venison for domestic consumption

(O‟Connor 2006; RIRDC 2007) but in 2008, only 15 tonnes was reported (Zemke-

Smith 2009).

In the financial year 1999/2000, Australia processed 60,165 animals to produce

1,928 tonnes of venison (Tuckwell 2007). In 2000/2001 in Australia, 45,757 deer

were slaughtered to produce 1,680 tonnes of venison (RIRDC 2007). Of these,

Chapter Two

24

18,026 were red deer that produced 963 tonnes with an average HCW of 53.4 kg, and

27,647 fallow deer that produced 651 tonnes of venison with average HCW of 23.5

kg. The remainder were comprised of 1,851 rusa deer that produced 65 tonnes of

venison with average HCW of 35 kg (RIRDC 2007). In 2001/2002, production had

declined to 1,489 tonnes of venison from 41,223 animals (Tuckwell 2007). In

2002/2003, 46,652 animals were processed to produce 1,505 tonnes of venison. In

2003/2004, Australian production had decreased to 1,087 tonnes of venison from

30,850 animals (McRae et al 2006). In 2004/2005, there was a slight increase with

31,061 animals processed to produce 1,174 tonnes of venison. It is speculated that

increases in slaughter numbers in the early years of this century were due to the

drought, with a number of producers leaving the industry or sending most of their

stock to slaughter due their inability to feed them. In 2005/2006, 27,305 animals

were processed to produce 1,012 tonnes of venison and in 2006/2007, 12,857

animals were processed to produce only 461 tonnes of venison (Tuckwell 2007). By

2007/2008 this had increased slightly: 15,496 animals were slaughtered for 576

tonnes of venison, with a possible reason for this being the slaughter of entire herds

due to producers leaving the industry. In 2008/2009, there were 11,021 animals

slaughtered to produce 476 tonnes of venison and an unknown number of animals

slaughtered in 2009/2010 to produce only 329 tonnes of venison (Figure 2.1)

(McKinnon 2011; Shapiro 2010). From slaughter data it appears that many breeding

females were sent to slaughter in recent years, thereby reducing the ability for the

industry to expand. The extended drought (2000-2009) also led many producers to

not join their breeding females, exacerbating the problem (Shapiro 2010).

Chapter Two

25

Figure 2.1 : Australian deer processed and venison produced (deer numbers estimated

for 2009/2010)

During the peak industry period of 1999 to 2001 venison carcass prices paid to

producers, averaged $4.80 per kg for fallow deer and $5.60 per kg for red deer

(Tuckwell 2003a). Prices dropped soon after due to the sudden availability of

relatively cheap, high quality beef throughout Europe (Tuckwell 2003a). In

2006/2007, the prices per kg for venison were an average of $2.70 per kg HCW with

a premium of $4 per kg paid for prime animals within optimal carcass weight ranges

(RIRDC 2007). The current price per kilogram (2011) for venison has increased

slightly with premium red deer carcasses attracting $4.80 to $5.00 per kg HCW and

$4.50 per kg HCW for premium weight fallow deer of HCW over 20 kg (Hansen

2011). Animals not reaching premium schedules as a result of advancing age or low

carcass weight are worth $3.00 to $4.00 per kg HCW. These changes are largely

attributable to newly instituted strategic alliances between processors and producers

(Hansen 2011). However, returns to producers are reduced as a result of high

transport costs due to the low number of export accredited abattoirs in Australia and

the distances required to truck animals to them for processing (Hansen 2011). The

gross value of production (GVP) of the Australian deer industry in 2006 was a

modest $5 million per annum (RIRDC 2007) compared with other red meat

industries: beef cattle at $7,436 million and sheep at $2,168 million (Fletcher et al

2009).

0

10000

20000

30000

40000

50000

60000

70000

Venison produced

(tonnes)

Deer nos. Processed

Chapter Two

26

In contrast, Australia produced 2.15 million tonnes of beef and veal with a gross

value of $7.4 billion, 435,000 tonnes of lamb and 258,000 tonnes of mutton in 2008,

with a gross value of sheep meat of $2.2 billion (Fletcher et al 2009). Australian

lamb production in 2010 was estimated at 412,000 tonnes, with slaughter stock

numbers of 8.6 million head from total stock numbers of around 68 million head on

22,858 farms. The saleyard price of lamb averaged around $4.70 per kg (dressed

weight). Total weight of lamb exported was estimated at 250 kilotonnes (Rees 2010).

Australian beef and veal production in 2010 was estimated at 2.1 million tonnes with

slaughter stock number of around 8.4 million head from total cattle stock numbers of

28.5 million on 49,757 farms. The weight of beef exported was estimated at 910

kilotonnes with an average saleyard price of $2.99 per kg (dressed weight) (Perry

2010). Red meat production and exports accounted for almost 22% of the total gross

value of Australian agricultural production in 2008 (Fletcher et al 2009).

2.1.6: Venison specifications

In 1995, AUS-MEAT instituted a common venison language in an attempt to

standardise and apply consistency to Australian product on the market. The

specifications document provided a common language and accurately described a

core range of cuts for the meat trade. The aim was to increase quality by providing

accepted product description and quality standards (AUS-MEAT 1995) (Plates 2.1.

and 2.2).

In 2001, RIRDC published a venison processing standards manual for marketers and

processors of Australian venison. The manual incorporated detail on best practice for

the supply chain from production to distribution as part of the Quality Management

Programme (RIRDC 2001). Selection of animals for processing specified that body

condition and animal age are critical factors influencing venison quality. The manual

provided a vague descriptor for producers of „minimum fat over the rump‟ and

referred readers to detailed BCS charts (Appendix 1 and 2), and specified the age of

supply of fallow deer bucks at two years immediately prior to the rut (RIRDC 2001).

Chapter Two

27

Plate 2.1 : Examples of AUS-MEAT venison language and descriptions for some bone-

in cuts.

Plate 2.2: Examples of AUS-MEAT venison language and descriptions for some

boneless cuts.

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28

2.2: Measures of meat quality

2.2.1: Meat from muscle

Evidence from many civilisations verifies that meat has formed a part of the human

diet since ancient times (Belitz and Grosch 2009). Meat is skeletal muscle from

animals that is used for food. It is essentially dead muscle which derives its final

properties from the live muscle attributes as well as the effects of post-slaughter

processing. The study of meat quality requires an understanding of breeding and

genetics, pre-slaughter body condition and stress, the slaughter process, and various

post-slaughter processes along with muscle composition and structure, storage,

packaging, distribution and consumer handling (Devine 2011).

Muscles are composed of bundles of fibres or muscle cells held together with

connective tissue, and make up the lean portion of meat (Figure 2.1). The thickness

of the muscle fibres, the size of the fibre bundles, and the amount of connective

tissue binding them together contribute to the eating quality of the meat. The fibres

are long, thin, parallel, multinucleated cells of varying lengths and diameter. Fibres

are composed of smaller structures called myofibrils, which are the contractile units

of the muscle fibre. Approximately 2,000 myofibrils of approximately 1µm in

diameter are found in an average sized fibre (Ranken 2000). Molecules of the

proteins actin, tropomyosin and troponin are contained within. The myofibrils are

surrounded and embedded in the sarcoplasm matrix. Microscopically, muscle tissue

has a pattern of cross striations. Light and dark banding is produced by an order

arrangement of thin actin filaments and thicker myosin filaments. Tropomyosin is

located along the length of the thin filaments along with α-actinin in the Z-disk, a

structure that is believed to hold the thin filaments in a z shaped line. Actin and

myosin form actomyosin as they slide past each other during muscle contraction

(Figure 2.2). Adenosine triphosphate (ATP) supplies the energy necessary for the

muscle to contract. The meat of game animals, such as deer, consists of fragile fibres

with a firm consistency, accompanied by low amounts of connective and adipose

tissue (Belitz and Grosch 2009; Daszkiewicz et al 2009).

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29

Figure 2.2 : Diagram of muscle and fibre structure (Ranken 2000).

Muscle fibres are supported by connective tissue. Each muscle fibre is enclosed

within a membranous cell, or sarcolemma, and groups are organised into bundles by

a network of connective tissue called the endomysium. Each bundle is surrounded by

a sheet of connective tissue called the perimysium; a group of these bundles forms

the muscle and is surrounded by an outer layer of connective tissue called the

epimysium. Connective tissue is made up of two fibrous proteins, collagen and

elastin (Belitz and Grosch 2009). Muscles with adhering fat removed have an

average composition of 76% moisture, 21.5% N-substances, 1.5% fat and 1%

minerals with the remainder being small varying amounts of carbohydrate. There are

three basic protein groups within the muscle: those of the contractile tissue,

actomyosin, tropomyosin and troponin; the soluble proteins, myoglobin and

Chapter Two

30

enzymes; and the insoluble proteins, connective tissue and membrane proteins

(Belitz and Grosch 2009).

Many individual muscles are bound in clusters by membrane and silver skin and this

must be removed to improve the eating performance. Denvering is a process used to

remove the outer layer of connective tissue on a meat cut. The denvering of venison

upgrades the value of the cuts making venison better suited for consumer ready

portions (Wright 1993).

At slaughter, muscle begins the biochemical process of becoming meat. Once blood

circulation ceases, oxygen is no longer supplied to the muscle and anaerobic

conditions start to develop. Energy rich phosphates such as creatine phosphate, ATP

and adenosine diphosphate (ADP) are degraded. The sole remaining source of energy

stems from glycolysis, which is pH and temperature dependent and influenced by the

presence of glycogen stored in the muscle tissue (Ranken 2000). The pH of the

muscle decreases post-slaughter from the living tissue range of 7.0-7.2 to around 5.5.

With depletion of the oxygen supply to the tissues, lactic acid, which is produced

from glycogen, the energy store in the muscle, accumulates and results in the

decrease of muscle pH. Once the muscle is critically low in ATP, the myosin heads

begin to bind to the actin filaments, producing actomyosin causing a lack of

extensibility in the muscle (Pearce et al 2011). This process occurs a few hours post-

mortem and the carcass becomes rigid as rigor mortis sets in. This state of rigor , is

accompanied by depletion of ATP from the tissues and the formation of actomyosin

as the actin and myosin filaments slide past each other during contraction of the

muscle. Actomyosin is responsible for the tension in the muscles. As rigor proceeds,

the surface tissue of the muscle becomes wetter and drip, or muscle exudates,

increase (Belitz and Grosch 2009). Approximately two to three days after the

establishment of rigor, the muscles soften again, the fibres straighten, and breaks

appear in muscle fibres. The breaks, or autolysis, occur at the Z line where actin

filaments separate as a result of endogenous proteinases. This degradation of muscle

fibres will continue as the carcass or cut ages during proteolysis (Penfield and

Campbell 1990).

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31

Meat undergoes physical and chemical changes when heat is applied. At

approximately 38ºC, the proteins are denatured as the hydrogen and covalent bonds

that hold the native structure of the protein together begin to break, thus allowing

them to uncoil making them susceptible to coagulation. This coagulation is visible as

the meat becomes more opaque: the coagulated filaments block light rays and lose

moisture. As the length of the amino acid chain extends, their side groups become

more exposed and their reactivity sanctions the creation of new bonds, including

disulfide bonds. Water that was once trapped in the coiled structures and surrounding

areas is squeezed out of the tissue. Muscle fibres shrink in width at around 54ºC and

they shorten as temperatures rise. By the time temperatures have reached 77ºC the

cells deteriorate and break. The breaks are a manifestation of the chemical changes

occurring in the actin and myosin proteins and the physical weakening of cell

structures which allows the contents to escape. Individual proteins display different

levels of thermal sensitivity with denaturation of myosin near 55ºC, actins between

70ºC and 80ºC, whilst the sarcoplasmic proteins denature over a range of 40ºC to

90ºC (Charley and Weaver 1997). Meat in cooked form becomes more solid and is

generally tougher and less juicy than the raw sample. However, if meat continues to

cook above 60ºC, later tenderisation may result due to softening of the connective

tissue, particularly in the presence of moisture. The cooking method is one of the

most important factors in eating quality and should be used to optimise the

performance of meat (McGee 2004).

Meat has very weak aroma when raw but develops a completely different flavour and

aroma profile after cooking. The final flavour and aroma will vary as a result of pre-

slaughter factors such as type of feed consumed, body condition of animals and pre-

slaughter stress, as well as the time, temperature and method of cooking.

Development of flavour is believed to be a complex characteristic arising from the

presence of lactones, acyclic sulphur containing compounds and aromatic and non

aromatic heterocyclic compounds containing sulphur, nitrogen and oxygen.

Differences in the precursors of these compounds may vary between species, thereby

explaining the differing flavour profiles (Penfield and Campbell 1990). The Maillard

reaction is an integral part of the development of meat flavour, and is a form of

nonenzymatic browning. It results from a chemical reaction between an amino acid

and a reducing sugar, usually requiring heat (Ranken 2000)

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32

Meat quality refers to product characteristics which meet or exceed consumer

expectation. Meat quality includes attributes such as yield, safety, appearance,

palatability and image. Many quality attributes are affected on farm, pre-slaughter

and post-slaughter. Therefore quality assurance (QA) is required in a paddock-to-

plate approach. Quality improvement, in order to be successful, must be driven by

consumer expectations and perceptions as they are the ultimate product user. It has

been demonstrated that consumer preferences do not always equate with traditional

carcass grades (Issanchou 1996). Much previous research looks at quality from the

angle of yield and production traits. Considerable research on increasing yields has

been conducted but this is of least importance to the consumer. Eating quality and a

positive eating experience should be of primary concern to producers and exporters

of venison (Stevenson-Barry 2000b). Quality assurance begins on the farm, and

involves animal husbandry, breeding and genetics, animal nutrition, transport and

slaughter (McKendry 1993).

Production of meat that satisfies or exceeds consumer expectations with regard to

eating quality is central to the future of the deer industry. Eating quality for red meat

may be defined as consumer perception of meat that is tender or tough, juicy or dry,

flavoursome and free from taints (MTU 1999).

2.2.2: Factors affecting meat quality

The concept of meat quality is multifaceted and involves sensory perception,

nutritive value, hygiene, toxicology and technological factors (Oddy et al 2001). The

quality of meat is affected by both genetic and environmental factors. Genetic factors

are those associated with heredity, where individual genes influence the development

of a trait in the context of a particular environment. Environmental influences on

meat quality are those not attributable to genetics, such as factors associated with

animals on farm, pre-slaughter and post-slaughter processing (Warner et al 2010).

The final eating quality of meat is affected by both intrinsic and extrinsic factors. The

intrinsic factors include structural and compositional characteristics, which to a

certain extent are affected by on farm production but are less easily controlled and

Chapter Two

33

managed than extrinsic factors. Extrinsic factors prevail during animal production,

slaughter, processing and finally, preparation for consumption (Ferguson et al 2001;

Warner et al 2010).

There are a number of measurements commonly used by meat scientists for meat

description that can also indicate changes to meat quality for eating, cooking, storage

and processing purposes. For example, meat tenderness is determined from the

contribution of sarcomere length, amount and solubility of connective tissue, as well

as rate of proteolysis during ageing and levels of intramuscular fat (IMF) (Warner et

al 2010). It is well known, for instance, that muscle pH is associated with meat

tenderness, one of the most important consumer perception traits of meat, and pH

affects other important attributes like meat colour and water-holding properties

(Hood and Tarrant 1981). The colour of meat, fresh and after chilled or frozen

storage, is an important characteristic for marketing, as customer selection is often

associated with the appearance of the product to the exclusion of other characteristics

that are just as important but not readily discernible to the naked eye (Risvik 1994).

Water holding capacity is another characteristic of meat that is connected to

consumer perception of fresh, chilled or frozen/thawed meat, and is also an important

measurement for processors wanting to manufacture value added meat products and

smallgoods. The drip loss (purge) often found in trays or packaging when meat is

stored for various lengths of time can accelerate meat deterioration and can also

decrease the attractiveness of the product for consumers, whilst processors need this

information to incorporate into processing technologies for a range of meat products.

Some of the key measures of assessing meat quality will now be outlined, and are

examined in more detail in the following chapters.

2.2.2.1: Muscle pH

At time of death, muscle pH in ruminant species is around 7.0-7.2. This will decrease

to reach a value of approximately 5.5-5.6 (Pearce et al 2011). When the pH decline

ceases, it has reached ultimate pH (pHu) and which is usually measured around 24

hours post-mortem. Ultimate pH has a profound effect on meat quality: it is more

significant than the age of the animal and also impacts on shelf life, juiciness, texture

Chapter Two

34

and flavour (Pearce et al 2011). Rate of pH decline from around 7.0-7.2 at slaughter

in relation to muscle temperature is crucial to eating quality. Rate of decline is

variable and can be reached 1-48 hours post-mortem in beef (Thompson 2002).

Optimal tenderness is achieved in beef when the pH is less than 6.0 with a core body

temperature in the range of 10-20C (Thompson 2002). If temperature fall is rapid

and pH decline is slow, carcasses cold shorten and become extremely tough. If pH

fall is rapid and muscle temperature decline is slow, muscles heat shorten, which

makes meat slightly tougher and less juicy, and brings about colour changes and

excessive drip loss, accompanied by a lack of improvement with ageing. Enzymes

involved during ageing are denatured by low pH/high temp conditions (Thompson

2002). Therefore, if the muscle pH is greater than 6.0 at a core body or deep muscle

temperature of less than 12C (fast cooling), then the resultant meat will be

extremely tough and the carcass will have been classified as cold shortened. If

muscle pH is less than 5.9 at deep muscle temperatures greater than 30C (slow

cooling), then there will also be a loss of tenderness and juiciness, and the carcass

will have been classified as heat shortened. If pH fall is not as it should be, a number

of post-slaughter carcass management alterations can be made, such as using

electrical stimulation which accelerates the rate of pH decline in beef (Thompson

2002).

A study by Hannula and Puolanne (2004) determined that muscle pH needs to be at

or below 5.7 by the time the core body temperature reached 7ºC to achieve optimal

quality characteristics. Meat scientists agree that the rate of decline and pH at a

specified temperature affects meat tenderness, but have difficulty defining the exact

relationship (Shaw 2000).

Rate of pH decline is a function of carcass size and fat cover over the major primal

muscles (Stevenson-Barry 2000a). Abattoir conditions also affect pH, such as time

from stunning and exsanguination to the chiller, temperature of the slaughter floor

and the chilling environment (Mulley et al 2010). All electrical inputs have an effect.

Temperature and pH temperature decline begins on the slaughter floor and finishes in

the chiller when the carcass has reached its pHu. It is assessed by taking sequential

pH and temperature readings on a number of carcasses as they come off the floor and

Chapter Two

35

then at timed intervals until ultimate pH is achieved in the chiller. The time taken

determines the rate of pH decline (Stevenson-Barry 2000a).

Muscle pH is affected by pre-slaughter stresses caused by fasting, dehydration,

unfamiliar surroundings, transportation, human contact, social structure variation

through separation and mixing in lairage, sudden climatic changes, under

nourishment and over exercise (Ferguson et al 2001). These factors reduce muscle

energy (glycogen) stores. After death glycogen converts to lactic acid. Low glycogen

levels lead to production of less lactic acid than required to produce desirable pHu

levels. In well fed, non-stressed cattle and sheep, muscle glycogen levels range

between 1 and 2% of muscle weight (Ferguson et al 2001). When levels fall below

1%, less acid is produced post-mortem resulting in higher pHu. Healthy, well fed

cattle can afford to lose some glycogen (20-30%) without affecting pHu (MSA 2010).

When animals are stressed they are likely to be depleted of muscle glycogen stores. It

takes at least four to five days for glycogen levels in muscle to be restored once they

have been metabolised. Meat and Livestock Australia (MSA 2010) also recommends

that cattle with poor temperament or under extreme stress are not consigned. By not

mixing cattle from different mobs within two weeks of dispatch, it was reported

(MSA 2010) that pHu was not adversely affected. Loading without the use of goads

or electric prodders also reduced animal stress and resultant high pHu values (MSA

2010).

Time in lairage has an effect on pre-slaughter stresses (MSA 2010). A minimum of

four to six hours is recommended, with a longer period (24-48 hours) more desirable

for cattle that have travelled over 1000 km. Cattle to be assigned MSA grades must

be slaughtered within 24 hours of leaving the farm to be eligible. In North America

slaughtering off the truck is common, but distances travelled are usually small.

Recent studies (MSA 2010) indicate that this practice may lower weight losses and

improved product eating quality. Some MSA studies have shown that strategic

administration of electrolyte preparations reduces the incidence of dark cutting and

carcass shrinkage during chilling (MSA 2001). All ruminants rely on bacteria in the

rumen to convert carbohydrates to glucose and the process of rumination takes more

time to replenish lost glycogen stores. Feeding aids in replenishment and studies

Chapter Two

36

have shown that feeding cattle high energy concentrate feeds immediately prior to

slaughter may reduce the incidence of dark cutting or high pHu meat (MSA 2001).

Ultimate pH of longissimus dorsi at the quartering point of a carcass should be less

than or equal to 5.7 for optimal eating quality. The relationship between pHu and

tenderness tends to be curvilinear, peaking around 5.9-6.2 (most tough). Whilst the

threshold of 5.7 could be challenged for its stringency, this reference point ensures

the MSA guarantee of tenderness for beef (MSA 2010). Ultimate pH values over 5.7

in a study on fallow deer were sometimes associated with a tough product (Shaw

2000, Hutchison et al 2010).

The pHu affects colour, appearance, texture and shelf life of red meat and is therefore

commonly used in meat grading systems around the world. It also appears to affect

eating quality. Attributes such as tenderness, flavour, odour, juiciness and functional

properties such as water holding capacity and microbiological spoilage have been

shown to be affected in research conducted on beef, lamb and pork (Belitz and

Grolsch 2009). It appears that toughness increases as pHu increases up to a value of 6

and then decreases, however, studies on deer show that fallow deer and reindeer meat

are uniformly tender regardless of pHu (Barnier et al 1999; Sims et al 2004).

Research has shown that a characteristic of game meats, such as venison, is a high

concentration of lactic acid, a product of anaerobic glycolysis, leading to high acidity

(Daszkiewicz et al 2009). Red deer venison is reported to be similar to beef and

lamb, where pHu above 5.8 is cause for concern and usually reflected a stressful

event pre-slaughter which affected meat quality (Stevenson-Barry 2000a). Many

cases of pH above 6 and 7 were recorded in that study.

High pH is often found around areas of bruising. Cases can lead to rejection of meat

along the marketing chain (MSA 2010). Meat with pHu levels above 5.7 tend to be of

lower and more variable eating quality. Meat with high pHu is common where

animals have been exposed to relatively long periods of stress and is known as dark

cutting or DFD (dry, firm and dark). The meat looks purple rather than the preferred

bright red, has a coarse texture, higher water holding capacity (it loses a lot of

moisture during cooking), reduced shelf life due to microbial growths due to high pH

and moisture, and appears undercooked despite extensive cooking (Wiklund et al

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37

1995). Low pHu meat is more common after exposure to a short period of acute

stress just prior to slaughter and results in PSE (pale, soft, exudative) meat which

renders the meat unacceptable in terms of meat processing or consumption

(Stevenson-Barry 2000a). Acceptable pHu is 5.3-5.7 for guaranteed eating quality

(Stevenson-Barry 2000a). The frequency of DFD in studies on red deer was 1.5%,

fallow deer 1% (Pollard et al 1999, 2000) and reindeer 6% (Wiklund et al 1995). The

figure for reindeer is largely due to the traditional methods of lassoing animals prior

to slaughter and in some cases, long transport distances (Wiklund et al 1995).

It has been shown that tenderness can be improved in beef and lamb through the

process of ageing or proteolysis. Hanging carcasses or vacuum packaging cuts and

holding at specified temperatures over extended periods of time can enhance the

eating quality (Thompson 2002). Studies show that lamb in the intermediate range

pH of 5.8-6.2 can be successfully aged to improve tenderness, however it was not

possible with beef (still over 8 kg shear force after 45 days where samples over 5 kg

shear force are considered tough). Proteolysis or ageing experiments with red deer

venison of intermediate pHu held at 4°C behaved like lamb, but tenderness was still

not as good or consistent as ideal pHu samples (Stevenson-Barry 2000a) in this study.

As mentioned previously, a number of pre-slaughter parameters may affect ultimate

pH. Work done on body condition in red deer hinds suggests that BCS has an effect

on pHu. Some emaciated animals were culled due to poor reproductive performance

and low body condition, and all were found to have high pHu compared with those in

good condition (Stevenson-Barry 2000a). As body condition increased ultimate pH

decreased.

A study on red/wapiti and fallow deer processed at a commercial abattoir in NZ

(Stevenson-Barry 2000b) reported many carcasses with high pHu. In that study, many

fallow deer had high pHu which was attributed to unsettled behaviour and handling

difficulties compared with red deer slaughter. However, eating quality of fallow deer

venison was not as affected as red deer venison at similar pHu levels. The study also

compared sheep with deer carcasses and found more cases of high pHu in sheep than

in deer. In this particular study, however, the sheep had been washed, were subjected

Chapter Two

38

to yarding by dogs, and electric prods were used as stock control methods. These

pre-slaughter stressors may be implicated in a high meat pHu.

Recent studies have identified links between temperament and pHu. In the NZ study

(Stevenson-Barry 2000a), antagonistic behaviour was similar across sexes for both

red and fallow deer. Red deer displayed more antagonistic, and fallow more

unsettled, behaviour. Prior to stunning, red deer were more settled than fallow.

Temperament is reported to have an effect on pH and meat quality. Similar studies

on cattle have shown that more excitable temperament and shorter flight times out of

the crush are linked to higher pHu. Preliminary work on red deer in NZ suggested

that flighty/skittish animals have higher pHu. Selection based on temperament may

be deemed to be good practice from an animal handling and meat quality point of

view. Calm cattle also made higher average weight gains (Stevenson-Barry 2000b)

and in New Zealand, investigations into selection of red deer according to

temperament are ongoing (Archer et al 2009; Quinn-Walsh 2010).

2.2.2.2: Chilling rate

The relationship between onset of rigor and pH is recognised as a key determinant of

meat quality. Rigor that occurs too early during the post-mortem period, while pH is

high, will result in myofibrillar shortening, known as cold shortening, and meat will

toughen. Similarly, carcasses that cool too slowly will also exhibit myofibrillar

shortening and this is referred to as heat shortening. Light and lean carcasses, such as

young deer, which have between 50% and 80% less carcass fat than sheep and lamb

or cattle (Drew 1985; Fisher et al 1998) are more liable to cool quickly and therefore

cold shorten, while large, heavy and fatter beef carcasses have a lower rate of

temperature decline and are more likely to exhibit heat shortening (Ferguson et al

2001). It is therefore important to control the temperature at which rigor is achieved.

The most effective way of controlling the temperature is via the chilling regime. An

effective chiller design and control of the air flow and rate of temperature decline in

the carcass is an effective way of minimising myofibrillar shortening. Ideally, rigor

should be completed somewhere between 10˚C and 20˚C to minimise the degree of

myofibrillar shortening (Ferguson et al 2001).

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39

2.2.2.3: Hanging method

One of the major causes of toughness in meat is shortening of muscle fibres

(Thompson 2002). Shortening also limits the benefits of ageing, or proteolysis. One

method used to reduce or prevent shortening is to hang carcasses using the pelvic

suspension technique. Pelvic suspension, also known as tenderstretch, is an

alternative means of hanging the carcass during chilling. The pelvic suspension

technique refers to hanging of a carcass by the pelvis (pelvic/aitch bone or

iliosacral/sacro-sciatic ligament) rather than the Achilles tendon. As the carcass is

chilled, fibres contract slightly and become rigid. During pelvic suspension, the legs

hang at a 90 degree angle to the body of the carcass. As a result, a number of muscles

are held in a stretched position so they cannot contract during rigor mortis (Plate

2.3). Pelvic suspension is most effective in the hindquarter muscles and has a varying

effect on each cut. In Achilles or traditional hanging (Plate 2.4), the spine is curved

and rear leg muscles have tension on them. When these muscles go through rigor

mortis they can contract. When this occurs the muscle fibres overlap resulting in

slightly tougher meat from beef carcasses (Ferguson et al 2001). Depending upon

chiller conditions, pelvic suspension generally results in improved palatability in beef

(Polkinghorne et al 2008a).

Plate 2.3: Split fallow deer carcass hung by the pelvic suspension technique.

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40

Plate 2.4 : Fallow deer carcass suspended by the Achilles tendon.

It has been reported in a study on beef by Ferguson et al (2001) that pelvic

suspension has a slightly negative effect on tenderloins (Psoas major) (which is

stretched in an Achilles carcass), is strongly positive in most hindquarter cuts and

neutral in the forequarter. It is a technique that has proven to be of benefit in tougher

Bos indicus beef carcasses (Ferguson et al 2001). This study also reported that pelvic

suspension affects the degree and rate of meat ageing. Pelvic suspension significantly

improved the tenderness score of hind quarter and loin cuts at five days post-mortem,

and altered the impact of ageing over time, but the reasons for this are not clear. This

means that reduced storage times are able to achieve desired levels of tenderness in

beef from pelvic suspended carcasses (Ferguson et al 2001). In that study the

relationship between pelvic suspension and meat tenderness was shown to be

variable for each cut and the characteristics of the carcass. In some beef and lamb

slaughtering facilities and in the venison industry, the technique of pelvic suspension

has not been widely adopted due to inconvenience, extra costs, changes in muscle

shape, additional chiller space requirements and a lack of financial incentives for

improved eating quality. Processing plants working within MSA guidelines quantify

the benefits by increasing returns and several MSA accredited abattoirs have adopted

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41

the process (MSA 2010). There are some alternative methods that do not involve the

whole carcass, using boned meat cuts which are held in stretched form via packaging

(Hopkins 2011).

2.2.2.4: Muscle ageing

It is well recognised that tenderness is a highly valued consumer trait (Huff Lonergan

et al 2010) followed by flavour (Warner et al 2010). Ageing is a process used to

improve tenderness and flavour in meat and may involve techniques such as

extending carcass hanging time and long term storage of cuts in vacuum packs.

Ageing occurs as the muscle fibres break down slowly due to naturally occurring

proteolytic enzymes. During proteolysis the muscle fibres are weakened and meat

becomes more tender. Macroscopic appearance does not change as the change occurs

at a microscopic level with degradation of the Z disks and myofibril breakage (Figure

2.3) (Aberle et al 2001). There are three accepted endogenous proteinase systems

involved in proteolysis: the calcium dependent calpain system, lysosomal cathepsins

and proteosome, with the relative contribution of each causing considerable debate

(Ferguson et al 2001). Ageing is temperature and pH dependent and the effect of

ageing decreases over time, with most improvement in the first 21 days post-

slaughter. Higher temperatures result in more rapid proteolysis. The rate and extent

of glycolysis and proteolysis are the primary biochemical changes that determine

myofibrillar tenderness or toughness (Ferguson et al 2001; Warner et al 2010). Meat

can be aged in carcass form, on the bone-in primals (up to 14 days) or when vacuum

packed for long periods (up to 12 weeks). Over-aged meat develops off odours and

can give beef a liver taint. All MSA products have a minimum ageing time of five

days that is easily achieved by the butcher and packaged meat trades. Ageing meat

requires refrigerated storage which adds cost (MSA 2001).

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42

Figure 2.3 : Meat ageing. At x12500 magnification (A) Intact 1h post-mortem, (B) 24h

post-mortem some Z disk degradation, (C) 48h post-mortem Z disk degradation and

myofibril breakage is extensive, at x650 magnification (D) 8 days post-mortem

complete lateral breaks of myofibrils (Aberle et al 2001).

Research conducted by the New Zealand deer industry recommends that deer

carcasses, regardless of species, be held at 10ºC for 24 hours prior to chilling to

enhance the effects of ageing (Drew et al 1988; Drew and Stevenson 1992).

2.2.2.5: Electrical stimulation

Electrical stimulation increases the rate of decline of pH, or accelerates post-mortem

glycolysis, hastening the onset of rigor (Hopkins 2011). In this way, the temperature

of rigor can be optimised for rapid tenderising and the chance of cold shortening is

minimised as the muscles enter rigor prior to the muscle temperature falling

sufficiently to induce cold shortening (Hopkins 2011; Young et al 2005).

Electrical stimulation is used routinely with red deer in New Zealand but not in

Australia. Studies by Drew et al (1988) demonstrated that electrical inputs had a less

significant effect on fallow deer carcasses, and that more research is required to

quantify the benefits. This research has not yet been conducted.

Chapter Two

43

2.2.2.6: Ossification

Skeletal ossification may also be measured as an effect on meat eating quality. It

measures the physiological maturity of the carcass. As an animal matures, cartilage

present around bones gradually fills with blood and calcifies into bone. Although

ossification largely occurs in association with the animal‟s chronological age, it can

also be affected by nutrition and development. It is measured visually during chiller

assessment by the grader. Eating quality declines as ossification increases (MSA

2010). MSA relates carcass weight to ossification, essentially a weight for age

measure. Cuts from carcasses at the same weight with lower ossification are graded

higher. It has been reported that cattle fed poor diets are likely to have higher

ossification. Cattle with fast growth rates will reach slaughter weight at a younger

age and reduced ossification (MSA 2001). In deer, faster growth rates resulted in

greater consumer acceptance of flavour in venison (Wiklund et al 2008).

2.2.2.7: Texture

Texture is a complex descriptor which incorporates the tenderness of meat. It also

incorporates the sensory parameters of chewiness, juiciness, softness and the muscle

fibre and connective tissue components of tenderness. Tenderness involves the

interaction of water holding capacity, muscle fibre proteins and their ultrastructures,

connective tissue proteins and fat content (Penfield and Campbell 1990). Tenderness

is a function of a number of parameters in the production and processing systems

through to the preparation method used by the consumer to cook meat (Thompson

2002).

Pre-slaughter parameters such as animal species, age, activity and ante-mortem stress

along with post-slaughter processes, including development of rigor, hanging

method, ageing, chilling and electrical stimulation have all been shown to affect meat

texture (Tornberg 1996).

Muscle fibre diameter is also related to the tenderness of cooked meat, along with the

end point temperature. Muscle fibres with small diameters result in more tender

meat. Higher end point temperatures will result in less tender meat as the network

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44

structure of proteins is tightened. Sarcomere length also affects tenderness, with

shorter sarcomeres being associated with toughness. Muscles with large amounts of

connective tissue are less tender (Warner et al 2010). Muscles that are in constant use

contain more collagen than less frequently used muscles. The amount of collagen

does not increase with animal age, however, the number and strength of the bonds

between peptide chains does increase, decreasing the amount of collagen that can be

solubilised when cooking (Penfield and Campbell 1990; Warner et al 2010).

The amount, distribution and composition of the intramuscular connective tissue

varies within muscles of the carcass and with the age of the animal slaughtered. It

has long been implicated in the toughness of meat. Cooking increases the strength of

the connective tissue in the internal temperature range of 20˚C to 50˚C, and it

decreases in strength with higher internal temperatures and longer cooking times,

particularly in the presence of moisture which hydrolyses the collagen component of

the connective tissue to gelatine. Cross linking of collagen in older animals is

believed to result in tougher meat, however, definitive links have not been

established. Amounts and composition of connective tissue may be manipulated by

animal nutrition and exercise, and affect the resultant meat texture (Purslow 2005).

2.2.2.8: Water holding capacity and drip loss

Water holding capacity is an important determinant of meat quality. It is integrally

involved in meat appearance prior to cooking, juiciness and sensory attributes

associated with mastication (Lawrie and Ledward 2006). A large component of

muscle is water. Typically meat is approximately 75% water by weight, and a small

proportion of this water, approximately 5%, is bound very closely to muscle proteins

via hydrogen and hydrophobic bonds (Huff-Lonergan and Lonergan 2005). Most of

the remaining free water is located within three dimensional spaces in the muscle

fibres, held by capillary forces between the thick and thin filaments, with a small

percentage located within connective tissue and the sarcoplasm (Huff-Lonergan and

Lonergan 2005). Water is held either within the myofibrils, or between them and the

sarcolemma between muscle cells and muscle bundles (Huff-Lonergan and Lonergan

2005).

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The extent of water holding by the protein network depends upon the amount of

cross linking among the peptide chains (Belitz and Grolsch 2009) and a number of

factors relating to the tissue itself and how it is handled post-slaughter (Huff-

Lonergan and Lonergan 2005). When the structures are disrupted the ability of the

meat to hold water is compromised. Proteolysis, changes in pH, cutting, freezing and

heating will all damage the cell walls and reduce water holding capacity (Penfield

and Campbell 1990). One of the many benefits of ageing of meat has been

improvement of water holding capacity, which is also enhanced by higher levels of

IMF (Lawrie and Ledward 2006). Issues with unsatisfactory water holding capacity

costs the meat industry millions of dollars annually. Research indicates that the rate

and extent of pH decline, proteolysis and protein oxidation are key parameters

controlling the ability of meat to retain moisture, with studies suggesting that

degradation of key cytoskeletal proteins by calpain proteinases also plays a role.

Rapid pH decline and/or low ultimate pH are implicated in low water holding

capacity and high purge losses due to protein denaturation. (Huff-Lonergan and

Lonergan 2005). The accelerated pH decline and/or resultant low ultimate pH causes

the myosin heads to denature and shrink, along with myofibrillar lateral shrinkage.

Denatured myosin loses the ability to retain water resulting in decreased water

holding capacity, and in the case of low ultimate pH: pale, soft, exudative meat

(PSE). This was previously a frequent condition in pig carcasses due to the high

prevalence of the Halothane gene, which was implicated in PSE cases (Pearce et al

2011). It has also been identified in grain-fed beef carcasses due to slower cooling

rates and rapid pH decline (Warner et al 2009). This is unlikely to be an issue for

lighter, faster cooling, deer carcasses (Drew 1985).

A large percentage of Australian venison is exported frozen, particularly to German

markets (Tuckwell 2007). One of the issues with freezing meat is the amount of

exudate that is expelled upon thawing. When muscles are frozen, water held within

the cells is squeezed out providing a reservoir of fluid to exude upon thawing

(Lawrie and Ledward 2006). Cellular damage is also possible, with the extent

dependent upon the quality and speed at which the muscle passes from -1ºC to -7ºC,

or freezing time. Faster freezing times result in less cellular damage and less

exudate upon thawing. This factor interacts with post-mortem ageing treatment and

thawing conditions (Anon and Calvelo 1980).

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46

2.2.2.9: Meat colour

The colour of muscle tissue is normally a purple/red hue due to the iron rich pigment,

myoglobin. Myoglobin is a water soluble protein that stores oxygen for the aerobic

metabolism in the muscle. It consists of a protein component and a non-protein

porphyrin ring with a central iron atom. The iron atom is an important determinant of

meat colour. Haemoglobin is found in the blood and therefore also contributes to the

colour of meat. Both of these conjugated protein pigments combine with oxygen to

assist metabolic processes, particularly in the live tissue. Haemoglobin is responsible

for oxygen transportation in the bloodstream, while myoglobin holds oxygen in the

tissue (Aberle et al 2001).

The amount of myoglobin in the muscle increases as the animal ages, therefore meat

from older animals is a darker red than young animals. Amounts of myoglobin also

vary with animal species and individual muscles within the same animal. Because

muscles vary greatly in their activity, their oxygen demand varies. As a consequence,

differing myoglobin concentrations are found in various muscles. Venison has a

characteristic dark red colour due to increased myoglobin in the muscle tissue

(Penfield and Campbell 1990), partially due to myoglobin induction as a result of

physical activity and a relatively high proportion and frequency of red muscle fibres,

(Aberle et al 2001) and high levels of iron (Drew and Seman 1987; Dahlan 2009).

This characteristic dark red colour can be off-putting to consumers who are

accustomed to the brighter, cherry red of beef or lamb. The colour also seems to

oxidise more rapidly than that of beef and lamb (Drew and Stevenson 1992; Wright

1993).

In living muscle tissue, purple/red myoglobin exists in balance with its bright red

oxygenated form, oxymyoglobin. After death the oxygen is utilised rapidly and meat

colour is reduced to purplish red. The cut surface of the meat quickly oxidizes and

exhibits the typical bright red hue of oxymyoglobin. Eventually a brownish colour

will form due to oxidation of the iron from a ferrous to ferric state, known as

metmyoglobin (MTU 2006a).

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47

The ultimate pH of meat affects meat colour. Meat that is high in pH takes on a

characteristic dark red colour and is referred to as DFD (dry, firm and dark). The

colour will gradually darken through the pH range of 5.4 to 7.0. Beef with a pH over

6.0 is referred to as dark cutting, however, consumers may regard beef with a pH of

5.8 as dark. The dark colour of red meat in the high pH range is caused by less

oxymyoglobin formation on the low acid surface. There is a similar reduction of

myoglobin below the surface, giving a dark appearance as a result of lower surface

light reflection as well as light scattering (MTU 2006a).

Colour changes occur in meat as a result of the cooking process. Reactions and

physical changes contribute to the colour as the surface is dehydrated and denatured

with heat. During cooking, myoglobin remains essentially unchanged until

approximately 60ºC, upon which disruption to the structure occurs. The oxygen

binding ability of myoglobin is lost, plus the iron atom releases an electron which in

turn causes the formation of a new tan coloured compound called hemichrome. By

approximately 80ºC, enough hemichrome has amassed that red meats take on a

brown-grey appearance, no myoglobin or red centre is found in the meat and it is

considered „well done‟ (McGee 2004). Surface browning is caused by decomposition

of fats, carbohydrate and proteins. The most common of these reactions is carbonyl-

amine browning or the Maillard reaction (Penfield and Campbell 1990).

2.2.2.10: Intramuscular fat

Intramuscular fat cells, or adipose tissue, are located in spaces in the perimysium,

most frequently along small blood vessels. Characteristics of fatty tissue vary

between species and according to pre-slaughter treatments, specifically manipulation

of feed (Warner et al 2010). Fatty acid composition will differ in degree of saturation

and in chain length. Most are saturated and monounsaturated, and as degree of

saturation increases, hardness of fat increases. Animal tissue also contains small

quantities of phospholipids. Cholesterol is associated with phospholipids in the

membranes of some cells (Penfield and Campbell 1990; Warner et al 2010).

During cooking fat is released from the cells by heat and is dispersed. This dispersed

fat lubricates the muscle fibres and connective tissue resulting in perceived

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48

tenderness and juiciness (Penfield and Campbell 1990). Some intramuscular fat is

necessary for optimal palatability (Devine 2001; Hopkins et al 2006). It is believed

that IMF has a direct relationship with the sensory parameters of juiciness and

flavour, and an indirect relationship with meat tenderness (Warner et al 2010). There

remains ongoing debate as to the benefits of fat marbling in relation to eating quality,

and whether improvements in eating quality justify the costs of achieving extensive

marbling.

Marbling is the intramuscular fat which appears as fine flecks within the muscle.

Marbling is a visual score given to a piece of meat, whereas IMF is the chemically

measured fat content including membrane lipids, although the two terms are often

used interchangeably (Warner et al 2010). Marbling is the last fat to be deposited and

the first to be utilised by the animal as an energy source. To maximise marbling, the

animal must be on a high nutritional plane. Marbling has a very positive effect on

eating quality of beef and is evidence of well fed animals (Devine 2001). It tends to

improve tenderness and juiciness. It is, however, possible to ensure good eating

quality without marbling if other factors are well managed. The United States

Department of Agriculture (USDA) grading schemes use marbling as an assessable

component and have done for more than 50 years, as has the Japanese Meat Grading

Association (JMGA) for the past 10 years, with premiums paid to producers

according the marbling levels. US consumers accept the role of marbling in meat

quality, as do Japanese consumers. The system works well for these countries where

uniform production methods are in place and do not give rise to the variations seen in

Australia in relation to carcass weight, breed, age, fatness and finishing regime

(MTU 2005).

The MSA and AUS-MEAT schemes utilise a similar system of marbling score as

part of their meat quality grading programs. Australian consumers have been shown

to assign higher scores for tenderness, juiciness, flavour and overall liking where

IMF is up to 14-17%, but not beyond that. Generally marbling accounts for between

3% and 10% of variation in tenderness scoring of beef (Warner et al 2010). Whether

Australian consumers come to accept high levels of marbling to be equated with

increased meat quality remains to be seen. Deer and other game meat species are

unlikely to achieve marbling within the muscle due to their naturally low levels of

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49

body fat. The lack of visible marbling in sheep and lamb meat, fish, chicken, pork,

venison, kangaroo and other game meats is not seen as a disadvantage but rather as a

marketing advantage in an emerging health conscious society (Devine 2001).

2.2.3: Consumer perception

The key to success for any product is to supply what the consumer desires. The most

important aspect of meat assessment occurs with the final product user, the consumer

(Oddy et al 2001). Markets may differ somewhat and suppliers need to be flexible in

their approach to marketing to a variety of consumers. In countries of affluence,

consumers demand meat products of high quality 100% of the time (Warner et al

2010). In terms of red meat quality, tenderness is known to be of paramount

importance to consumers, along with flavour (Troy and Kerry 2010). The red meat

industry, including that of venison, needs to invest in a consumer focused agenda in

order to be sustainable and increase profitability (Troy and Kerry 2010).

The ultimate determination of the quality of meat lies with the consumer. Consumers

define meat quality according to sensory quality, food safety, nutritional value and

convenience. The consumer uses both intrinsic cues such as appearance (visible fat),

colour and presentation, and extrinsic cues such as price, quality mark, and country

of origin along with production and nutritional information (Troy and Kerry 2010).

Repeat purchasing is only possible where the consumer is satisfied with the resultant

eating experience (Egan et al 2001). A study by Russell et al (2005) determined that

meat eating quality (65-68%) and price (25-28%) dominate decisions by consumers

to repeat purchase the product.

Product testing conducted with consumers or trained panels provides valuable data

that is not obtained by one dimensional testing such as objective measures of

tenderness, colour and other meat quality parameters. Measures of juiciness, flavour

and overall acceptability are not adequately obtained without the use of sensory

evaluation techniques (Thompson 2002).

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Consumer perception of quality is also largely determined by their beliefs and

attitudes to the product, which are largely culturally based. Venison exhibits

leanness, with a colour darker than the major meats (beef and lamb), and high

nutritional value. These quality attributes are hampered by a lack of availability

(particularly of domestic product), high price per kilogram, lack of consistency in

quality, lack of consumer knowledge on how to prepare it, and cultural acceptance

(the so called „Bambi‟ syndrome) in Australia (Janes 1993). Venison lends itself well

to Asian style food preparation of high heat and fast cooking times, which adds to the

convenience desired by consumers. The kangaroo industry have successfully dealt

with similar constraints including lack of cultural acceptance (the „Skippy‟ syndrome

and its common use as pet meat) (Beaton et al 2001) and availability. Kangaroo meat

can now be purchased in major supermarket chains around the country. This is also

possible for the Australian venison industry once producers have more ready access

to slaughter facilities. Similarly, lessons can be learnt from the New Zealand venison

industry with the introduction of the Cervena™ brand and a successful export

industry. Ironically, the majority of venison available in Australia is imported from

New Zealand. Due to venison‟s intrinsic and extrinsic quality attributes, it fits well

with consumer trends towards lighter, healthier, environmentally friendly, quality

assured foods. Assurance of consistency in venison quality is essential in order to

place the product successfully in consumer markets. Assurance can be brought about

by successful implementation of pre- and post-slaughter parameters in order to

optimise quality (Piasentier et al 2005).

Australian consumers place a great deal of emphasis on the leanness of meat

purchased for consumption at home, and rate tenderness as the most important eating

quality attribute followed by flavour (Egan et al 2001). Venison fits this profile well.

Egan et al (2001) concluded that consumers are becoming more educated,

demanding and critical in relation to the quality of food, and the meat industry must

face these challenges.

Lack of tenderness appears to be an issue for venison, particularly for meat from

males after the rut or breeding season. For maximum confidence in the quality of the

venison supply in Australia, Shaw (2000) recommended the use of sensory

evaluation systems similar to those developed for the MSA beef grading system. A

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51

laboratory device can only indicate whether a muscle is tender or tough, whereas a

consumer can give a more holistic picture relating to juiciness, texture, flavour and

overall liking or acceptability for consumption.

2.2.4: Beef and sheep meat quality improvement schemes

Meat Standards Australia began as an industry program in 1996 following intensive

consumer research on declining beef consumption (Polkinghorne et al 2008a). In

1983, Australians were eating 50 kg of beef per capita, declining to 33 kg by 2000,

and now stands at 39.6 kg (Fletcher et al 2009). Strategies were developed in order to

supply a more consistent quality product and to accurately describe palatability

(Polkinghorne et al 2008a). It is a cooperative program which rewards best practice

across all industry sectors and utilises a total quality management approach to predict

palatability in beef (Thompson et al 2008). MSA utilises a paddock-to-plate

approach in an attempt to obtain optimal beef eating quality (Thompson 2002). An

eating quality standards (EQS) program was developed and researchers identified

and quantified factors that could improve quality and consistency in beef. The

program became known as Meat Standards Australia (MSA) and continued to evolve

under the direction of Meat and Livestock Australia (MLA) (Polkinghorne et al

2008a). The MSA grading system maintains a focus on guaranteed eating quality for

the consumer through the utilisation of a total systems or TQM (total quality

management) approach to the control of factors affecting meat quality right through

the production, processing, value adding and distribution sectors (Thompson 2002).

The MSA grading scheme identifies critical control points (CCPs) in the meat

production system at all levels from on farm to consumption, and implements

controls in order to predict final product quality. Large scale consumer testing was

undertaken that allowed the CCPs to be ranked in terms of their potential impact on

final eating quality (Thompson 2002).

MSA is a cuts based grading system, rather than the traditional carcass based

grading, implemented in order to guarantee beef quality in the domestic market and

thereby increase confidence in, and consumption of, red meat (Polkinghorne and

Thompson 2010). Traditionally, carcass based grading systems such as those used by

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52

AUS-MEAT, USDA and JMGA, include descriptors of conformation and fat cover

(EUROP), skeletal maturity, marbling, meat colour, rib eye area, fat colour and depth

over a base of dentition and sex description (Polkinghorne 2006; Smith et al 2008).

These traditional grading schemes attempt to sort carcasses, often using

M.Longissimus dorsi (LD) as an indicator muscle, according to predicted eating

quality, however, the variations between assigned grades accounted for little

variation in palatability results when placed with consumers (Smith, et al 2008;

Thompson and Polkinghorne 2008).

The MSA cuts based system assigns an individual grade to muscles from the same

carcass to reflect expected differences in eating quality (Smith et al 2008). This is a

dramatic change from the traditional system of classifying carcasses into groups of

like appearance (Polkinghorne et al 2008b). Meat graded using the MSA system has

assigned a palatability score via the implementation of a palatability assured critical

control point (PACCP) and is labelled for consumers in order to provide a guarantee

of eating quality at three levels in conjunction with a suitable cooking method

(Polkinghorne 2006, Thompson and Polkinghorne 2008). The aim is to allow the

consumer to purchase and prepare beef with confidence. MSA product has a

minimum three star standard. Three stars is tenderness guaranteed, four star is

premium tenderness and five star, supreme tenderness. These grades are given to 40

individual carcass muscles, cooked by up to six alternative methods, thereby giving

the potential for assigning 137 grades to any one carcass for each number of days

aged (Polkinghorne et al 2008b).

This revolutionary approach involved the use of extensive consumer tasting panels to

aid in the identification and quantification of the critical control points (CCPs)

included in the model for eating quality predictability. The measures of tenderness,

juiciness, flavour and overall acceptability were combined into a single meat quality

score, and along with a palatability measure, formed a composite meat quality

(MQ4) score (Thompson et al 2008). Also included were inputs from pre- and post-

slaughter parameters such as breed, sex, ultimate pH, fat score and hanging method

(Polkinghorne et al 2008b; Polkinghorne and Thompson 2010).The scores were

calculated from data obtained from 32,000 cuts analysed by 68,000 consumer

panellists, with the use of a statistical prediction model (Polkinghorne et al 2008b;

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53

Polkinghorne and Thompson 2010). The uniqueness of the approach is the

traceability throughout the chain from paddock to plate. MSA provides feedback on

eating quality to the processor and producer. Linking price along the production

chain rewards and encourages approaches that improve beef quality and ultimately

consumer acceptance (Thompson et al 2008).

Grading is established by calculating the effect of factors relating to eating quality.

These include an animal‟s breed, sex, age, growth history, processing and chiller

assessment data along with individual cut and muscle, days of ageing (5-30) and

cooking method. A large database has been established with consumer sensory

scores, and MSA grades are set from analysis of consumer test results. The MSA

score is a composite of tenderness, juiciness, flavour and overall acceptability (MSA

2010).

Graders collate information provided by the cattle supplier (via MSA vendor

declaration) with abattoir information and chiller assessment detail. A statistical

calculation is made which estimates the interactive effect of all factors on eating

quality (MLA 2000).

The prediction parameters used in the MSA model are summarised as follows:

Percentage of Bos indicus content as specified by the producer and confirmed

with measurement of hump height. Bos indicus cattle tend to produce tougher

beef than Bos taurus.

Animal sex and ossification score, which is used in conjunction with carcass

weight to estimate growth rate effects and age, if unknown.

Stress and management practices, such as flight speed, time off feed and

mixing of groups prior to slaughter.

Carcass hanging method, either Achilles tendon, pelvic suspension from the

ligament, pelvic suspension from the aitch bone or tender cut.

Marbling score and rib fat. Higher levels increase the palatability of the meat.

Ultimate pH. Improvements in eating quality occur as pH declines from the

threshold of 5.7.

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54

Ageing period. Muscle ageing from 5 to 21 days has been shown to increase

beef palatability.

Cooking method: dry heat methods such as grilling, roasting and stir frying

for low connective tissue cuts, and moist heat methods such as stewing,

casseroling and braising for higher connective tissue cuts (Thompson 2002;

Polkinghorne et al 2008a).

In summary, Australian beef is graded with the following procedure: body number

and feed lot number, carcass weight, sex, percentage of Bos indicus content as this

tropical cattle genotype tends to produce less tender meat (Devine 2001), hanging

method, (Achilles tendon or pelvic suspension), ossification score, marbling score,

rib fat, pH and temperature. Other factors which do not impact on eating quality may

be taken at customers‟ request, such as meat colour, eye muscle area and fat colour

(MLA 2000). The MSA system is capable of underpinning a system whereby beef

producers are paid for quality as well as yield, while the consumer benefits from a

system which can accurately describe the eating quality of the beef that they

purchase (Thompson and Polkinghorne 2008). Current price premiums are being

generated from an MSA quality assured beef product, with payments to producers

being greater for MSA graded beef (Polkinghorne et al 2008b; Polkinghorne and

Thompson 2010). The adoption of MSA grading by the beef industry has resulted in

substantial change and improved awareness of the impact of various facets of the

supply chain on beef eating quality (Polkinghorne et al 2008b). Payments based on

consumer satisfaction, or value-based trading, is a powerful initiator for positive

industry change, with producers being paid for supplying what the consumer

demands (Polkinghorne and Thompson 2010).

Early this century, the Australian sheep meat industry identified a need for

improvements in eating quality and developed a framework and system of

classification to reliably predict eating quality in lamb, hogget and mutton products

(Russell et al 2005). Like beef, lamb was suffering from a decline in consumption

within the domestic market from 14.9 kg per capita in 1988 to 10.9 kg per capita in

1998, and ten years later, the figure stood at 10.4 kg (Fletcher et al 2009). Lamb was

also suffering from a lack of consistency in quality, particularly relating to

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55

tenderness, within a market of increased consumer expectation of premium quality

and value for money (Russell et al 2005).

The sheep meat eating quality (SMEQ) system was developed for use by producers

and processors for improvement of quality parameters (Hopkins 2011). The major

objectives of the eating quality assurance scheme were to describe and guarantee

eating quality of lamb and sheep meat products to consumers. Achieving this

objective would enable continuous improvement of product quality through all meat

production sectors with feedback to industry participants, much as MSA had done for

beef (Russell et al 2005).

Like the Australian beef industry before it, the lamb and sheep meat industry

identified a number of CCPs that may influence consumer acceptability of sheep

meat (Russell et al 2005), from live sheep genetics through to cooked meat (Young et

al 2005). These largely independent CCPs translated into a TQM system to improve

eating quality and reduce variability (Young et al 2005). A set of consumer

evaluation trials resulted in the development of a consumer eating quality score

(CEQ 0=poor, 100=excellent) which then provided a basis for the allocation of one

of 3 eating quality (EQ 1=inferior, 2= good everyday, 3=excellent) grades (Pleasants

et al 2005).

The prediction parameters used in the sheep meat eating quality model are

summarised as follows:

Choice of sire in relation to growth rate and muscling.

Animal age, determined by teeth eruption and wear, which is vital for

classification as lamb, hogget or mutton.

Nutrition: animals to be consuming a minimum of 50g per head per day.

Minimising stress at muster and slaughter through reduction in temperature

variations, noise and use of dogs. Good lairage design and skilled animal

handling.

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56

Carcass hanging method, either Achilles tendon, pelvic suspension from the

ligament, pelvic suspension from the aitch bone or tender cut and/or electrical

stimulation inputs.

GR fat depths.

Ultimate pH. Improvements in eating quality occur as pH declines from the

threshold of 5.7 (Hopkins 2011).

Improvements were achieved in the sheep meat industry with this shift to a consumer

focus and improvements in genetics, farm management and marketing. The industry

has achieved improved carcass weights, with future research focusing on

improvements in supply chain efficiency, reduction in carcass fatness and increase of

lean muscle (Pethick et al 2006). The Australian sheep industry, particularly the lamb

meat sector, has moved to a consumer focus when considering aspects of production

and processing (Hopkins 2011).

Consumer focused quality systems have been implemented internationally with the

advent of the New Zealand Beef and Lamb Quality Mark and the Cervena™ venison

quality brand, and the Blueprint for Eating Quality in the United Kingdom, which

marks a shift in the industry‟s focus from the producer to the consumer (Devine

2001). These systems are addressing the issue of variability in quality, particularly

tenderness, and developing „pathway‟ systems to ensure consumers can get branded

guaranteed tenderness. The Australian deer industry is currently investigating the

branding and quality marking of venison (McRae 2006). Recent research indicates

that consumers are willing to pay a premium for better eating quality (Polkinghorne

and Thompson 2010).

With eating quality grading standards in place for both the beef and sheep meat

industries, future research can focus on utilisation of genetic research to increase lean

meat yield, further eating quality studies, and the human nutritive value of red meat

(Pethick et al 2011).

If the venison industry intends to ensure optimal quality and tenderness of venison, it

is desirable for the industry to follow a similar pathway to that used by MSA and

SMEQ (Shaw 2000).

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2.2.5: Estimations of body condition

Body condition score (BCS) is a subjective assessment of flesh depths, including

muscle and fat, covering the animal‟s frame, as well as internal body fat reserves.

Estimations of BCS have traditionally been used in animal production systems to

relate the performance of animals to seasonal, nutritional, health and reproductive

variants (Flesch et al 2002). More recently these systems have been utilised in the

determination of suitability of livestock for live export (Gaden et al 2005). BCS

systems are useful due to their simplicity and efficiency at determining body

condition among animals of differing age, sex, frame size, muscling and weight. Live

weight, which is a common guide for assessing an animal‟s suitability for slaughter

or breed performance, does not account for differences in skeletal frame size,

muscling and fat accretion.

As animal condition increases from lean to fat, muscle volume also increases and fat

is deposited in various depots which vary between species. These developments are

evident via observation or palpation of key sites over the body. Descriptions of the

differences in condition have been documented for a number of species and

developed into body condition scoring systems. Most BCS systems developed for

domestic ruminants, including red and fallow deer, are based on a five point scale of

measurements that can be readily applied in the field, either by visual assessment or

palpation of the live animal. Examples of condition scoring systems for domestic

species include fallow deer (Flesch et al 2002), red deer (Audige et al 1998), pigs

(Elsley et al 1964), dairy cattle (Garnsworthy and Topps 1982; Gregory et al 1998),

beef cattle (Jansen et al 1985; Gresham et al 1986: Bullock et al 1991), sheep

(Hopkins et al 1995a), poultry (Gregory and Robins 1998) and goats (Mitchell 1986;

May et al 1995). None of these studies have linked BCS with meat eating quality.

Despite being subjective, these systems have some advantages over alternative

objective systems of assessing animal condition. Condition scoring requires minimal

training and results are generally consistent, no financial outlay is required for

specialised equipment, animal handling is not always required, and scoring is quick

and easy to perform (Gaden et al 2005). As with any subjective system, accuracy of

the assessor is key to its overall success. Numerous studies have shown that accuracy

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58

and repeatability are possible, especially with experienced scorers, with satisfactory

results from inexperienced assessors. Discrepancies will inevitably occur between

assessors, and a biological variation between animals also reduces accuracy.

Competency standards set by the National Livestock Reporting Service are an

attempt to improve assessor accuracy when estimating GR fat in sheep and goats

(Gaden et al 2005). Some objective measures have been developed to reduce the

subjectivity of the BCS system, however, many are financially or procedurally

inhibitive and it is often more practical and efficient to use manual methods. In

Australia, the current methods of assessing live animals in relation to carcass traits in

the major meat species of cattle, sheep and goats are AUS-MEAT live animal fat

scores. Fat scores are generally correlated with body condition scores, with some

exceptions in cattle (Gaden et al 2005).

Body condition scoring has been used extensively with dairy cattle in Australia via

systems such as the „Condition Magician‟, an eight point system which focuses detail

in the middle ranges where animals are deemed to be more productive (Gaden et al

2005). Beef cattle may be assessed using the AUS-MEAT live cattle language which

utilises fat scoring of subcutaneous fat depth at the P8 site (Gaden et al 20005) rather

than overall body condition. It is a useful indicator for market reporting of live cattle,

but lacks reliability in adequately describing body condition in very lean cattle.

Internationally, there are several condition scoring systems, predominately for dairy

and beef cattle. These scoring systems have been implemented widely for cattle and

are normally based around a five point system for beef and an 8-10 point system for

dairy cattle, with some detailing half scores (Gaden et al 2005).

The remaining meat species of sheep, goats, alpaca, camel, buffalo and deer all have

at least one simple system based around five body condition scores, with BCS 1

describing very lean animals and BCS 5 describing very fat animals (Gaden et al

2005). A number of systems operate on a fat score rather than a condition score, and

it takes skill on the part of the assessor to accurately estimate subcutaneous fat depth

in the live animal. Condition describes the amount of muscle and fat over the

skeleton, while fat score describes the amount of subcutaneous fat on an animal and

assumes a strong correlation between these scores and body condition. Subcutaneous

fat depth is an important carcass descriptor for meat animals in Australia, with AUS-

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Meat developing standard descriptions for the major meat species of cattle, sheep and

goats in the 1980s and 1990s. A system was not developed for the minor meat

species such as deer, but in 1995, AUS-MEAT published specifications for venison

cuts. Some systems are less reliable when dealing with very lean animals that may

still be in good condition, with variations in body size at the same fat depth, heavily

muscled animals with lower levels of subcutaneous fat, and individual variation in

distribution of fat over the carcass contributing to this. The use of fat score in

conjunction with BCS proved to be a more reliable indicator (Gaden et al 2005).

Fat scoring of carcasses is used extensively in Australian meat processing facilities.

The sites commonly used are the GR site, at the 12/13th rib, or the P8 rump site

which was selected, despite its less reliable indication of carcass fatness, as it

suffered less damage upon hide removal. These scores are combined with measures

of musculature, such as eye muscle area, to aid in determining price paid to

producers and in order to supply specified carcass quality to buyers (Pethick et al

2011).

Body condition scoring systems are used extensively in Australia for live animal

assessment and description for market related reasons such as livestock pricing, sale

by description and trade specifications, as well as for production purposes relating to

herd management and production, fertility and nutrition. To facilitate the translation

of objective descriptions of fat and muscle score into a mental image of the animal

being described, good quality photographs greatly assist the process and aid the

maintenance of standards of live animal assessment. These are particularly useful

with cattle; however, caution must be taken with species such as sheep, goats, deer

and alpaca, where coat and wool cover, especially in winter, may hamper visual

assessment. In these instances, palpation is necessary (Flesch et al 2002).

Recently, grading systems for meat, in particular beef, have related aspects of BCS to

meat eating quality, with many international markets now purchasing product using

USDA and Meat Standards Australia (MSA 2001) grading methods. There is now a

large amount of research data available on the eating quality of meat from a range of

domestic ruminant species, particularly sheep and cattle. Research on deer has so far

been limited, however, the eating quality aspects of reindeer (Rangifer tarandus

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tarandus) venison have been studied in relation to pre-slaughter handling and

supplementary feeding (Wiklund et al 1996b; 1997a; 2000; 2003a) and carcass

suspension methods (Wiklund et al 2011). The effects of various feeding regimens

on eating quality attributes in red deer venison have also been investigated (Wiklund

et al 2003c).

To encourage production of deer of consistent quality and to increase farmer returns

and consumer confidence for venison, BCS charts (Tuckwell et al 2000a; 2000b)

were developed for red and fallow deer (Appendices 1-3). The charts allow

producers to better assess their stock and use a common language, whereby

processors then have the ability to assess carcasses and pay accurately for the quality

they receive. It is anticipated that the use of these charts by deer farmers will lead to

improvements in venison quality and therefore consumer confidence.

Although most venison processors pay producers according to HCW and breed type,

few have attempted to differentiate payment on the basis of BCS. Processors

currently pay for a single HCW for animals of a species that fit within a weight range

irrespective of the animal‟s body condition. This system penalises those who produce

animals with ideal carcasses to cover losses incurred by animals in poor or over

condition. A system of visual assessment on the live animal plus objective HCW will

benefit farmers whose animals are in ideal condition and subsequently improve

venison quality. BCS could feasibly become a major factor that influences the price

paid to producers for their venison. The importance of bodyweight is clearly

demonstrated in payments currently made to producers for animals processed.

Producer payments should be increasingly based on a price grid determined by

factors such as age, sex, BCS and weight. In this way the industry has an opportunity

to improve the quality of venison available to international and domestic markets,

and subsequently provide a basis for improved confidence in local product (Tuckwell

and Tume, 2000).

Meat quality attributes such as tenderness, juiciness and flavour are not able to be

predicted by the appearance of the animal or the meat. By establishing links between

live animal body condition and carcass fatness with meat quality, predictions may be

possible. This, in turn, will aid producers when determining the optimal condition of

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animals for slaughter. Producers aim to achieve slaughter weights and process

animals at between 12 and 15 months of age, with red deer/elk hybrids and European

fallow/Mesopotamian hybrids able to achieve slaughter weights at 11-12 months.

Unlike cattle and sheep, deer are usually sold to a processor, not through a sale yard

or directly to an abattoir. Processors can then arrange transport, slaughter, packaging

and marketing (Horsley 2004). There are four major deer processing plants in

Australia: two in South Australia, one in the Central West region of New South

Wales and one in Western Australia (McKinnon 2011).

Currently, processors indicate that the ideal carcass weight for red deer is between 55

kg and 65 kg, and for fallow deer between 25 kg and 35 kg, but do not specify body

condition parameters despite referring to them in quality manuals (McRae et al

2006). Despite these guidelines, the average carcass weights for red deer and fallow

deer have fallen below the recommended weight ranges (McRae et al 2006;

Tuckwell 2007) and slaughter data show this trend has been continuing since 2000

(Tuckwell 2003a, 2007), with producers presenting processors with unfinished and

unsuitable animals for the premium venison market (Hansen 2004). With prices paid

to producers determined on an over the hook basis or HCW, returns are not as high

as they could be.

Tuckwell (2003b) recommended that Australian venison producers and processors

adopt QA programs and concentrate their efforts on influencing quality and therefore

profitability. These recommendations included feeding regimes to improve HCW in

a desired time frame, cost effectiveness in feeding programs, training in condition

score assessment of deer, and encouragement for processors to pay for carcasses

according to a pricing grid based on factors such as age, sex, BCS and HCW. This

would reward production of high quality carcasses and penalise poor production. The

Rural Industries Research and Development Corporation (RIRDC) is able to supply

processors with software to institute such grids (Tuckwell 2003a). Carcass weight

and carcass quality is under the direct control of the producer. Optimising quality of

supplied carcasses is under the control of the processor through slaughter and post-

slaughter processes.

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2.3: Industry issues

2.3.1: Background

The RIRDC has developed five year research and development plans for the

Australian deer industry. The purpose of the plans is to guide research and

development (R&D), provide clear direction and establish industry priorities for the

period. The first of these R&D plans commenced with the 1996-2000 plan, and new

plans have been developed for subsequent five year periods. At the commencement

of the first five year plan in 1996, the RIRDC-funded venison market development

project resulted in a large increase in international and domestic demand for

Australian venison. When export prices increased in the late 1990s, funding of

market development activities in the domestic market ceased. The strong domestic

market was lost when the limited volumes of venison produced were diverted to

higher paying export markets at the expense of the size of the national herd as

producers processed more animals to meet demands. The New Zealand deer industry

managed to secure this untapped Australian domestic market when export prices fell

as a way of selling venison previously sold in Europe (RIRDC 2007).

At the commencement of this project, the 2000-2005 RIRDC plan remained in place.

Both the first and second five year plans identified meat quality and quality

assurance as a key priority. These plans also identified the need for producers to

understand the impact they have on their financial returns. Producers have an

opportunity to improve the quality of animals produced, thereby improving venison

quality. One area identified was the poor live animal assessment skills of producers

and the need for them to utilise live animal assessment (or BCS) to help improve and

maintain quality and consistency of product. Venison R&D Objective 1 (2000-2005)

stated that „the average quality of animals processed by the Australian deer industry

varies greatly and is generally poor. Poor quality relates to lack of live animal

assessment standards, lack of management skills, lack of understanding of cost

benefits of improved management and absence of economies of scale‟ (RIRDC

2000).

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At the conclusion of this study, the 2006-2011 five year research and development

plan was drawing to a close. The goal of the current plan is to make the Australian

deer industry profitable and sustainable, with „efficient vertically integrated supply

chains‟ and effective marketing for a range of „internationally competitive products‟

(RIRDC 2007). The major focus of that document was on the establishment of

„market focused venison supply chain alliances‟ to sustain and develop the

diminishing Australian deer industry. The Australian deer industry is largely an

export focused one which leaves the participants vulnerable to the effects of unstable

trading conditions over which it has no control, such as international monetary

exchange rates and import regulations. These trading variables have driven the

industry towards a commodity approach to production and marketing with the export

market determining future production levels. This approach gives producers little

incentive to improve production and product quality due to the price taking approach

of commodity marketing. Prices offered by commodity markets do not support

profitable deer production in Australia. To provide producers with incentive and

thereby achieve sustainability for the deer industry, the formation of strategic

alliances within the supply chain was deemed necessary (RIRDC 2007).

The current five year plan has several specific objectives in place for the venison

industry in Australia. They include reducing the cost of production and processing,

improving value rewards in supply chains, promoting consumer awareness of

Australian venison attributes, and improving domestic and international marketing

strategies for Australian venison. They aim to do this by facilitating and promoting

adoption of existing knowledge by producers and processors incorporating industry

quality assurance schemes. There is a production target of over 80% slaughter

animals meeting the highest value carcass specification of processor price grids. To

meet this key performance index would support the establishment of supply chain

alliances while improving the technical capacity of the alliances to achieve high

value end market specifications. RIRDC propose to investigate the feasibility of on

farm slaughter systems and intends to review and improve the 1995 AUS-MEAT

terminology (RIRDC 2007).

In 2006, the agricultural industry in Australia was emerging from an extended

drought period which saw low commodity prices. These factors led to the Australian

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deer industry diminishing in size as many smaller producers exited from the industry,

while the larger producers, some with more than 1,000 head of deer, managed to

remain viable. Supply of venison products was also limited due to the slaughter of

young breeding females during this drought period, and subsequent reduction in herd

size over the following seasons (RIRDC 2007; Tuckwell 2007).

It is speculated that the major reasons for the industry downturn were the severe

drought in Eastern Australia between 2001 and 2003, a dramatic reduction in returns

for venison in 2003, and decreased confidence from producers in the industry. This

lack of confidence led to the slaughter of large numbers of breeding females at very

low prices, a reduction in new investment and a lack of herd expansion (RIRDC

2007).

The development of a competitive deer industry in Australia is only possible with the

adoption of efficient production and processing systems. Projects funded by RIRDC

to date have made available the knowledge required for producers and processors to

produce consistently high quality venison and velvet antler, and much has been

incorporated into the quality assurance program. The research projects conducted

have resulted in identification of the product parameters that define quality, yet

adoption of the necessary practices remained low because these practices usually

increase costs and to date they have not attracted price premiums. Tuckwell (2003a)

speculated that the future of the industry would be inextricably linked to its ability to

produce and market quality assured products. Due to the small size of the venison

industry in Australia compared with other red meat industries, the industry needs to

ensure that consumers have no quality-based reasons to reject its product but need to

be able to favourably consider Australian venison on the basis of its credibility and

quality (Tuckwell 2003a). Despite demand for high quality product in high value

markets, both international and domestic, the Australian deer industry has not

developed the capacity to meet market requirements in areas of product consistency,

quality and reliability of supply (RIRDC 2007).

Producers often equate quality with yield or hot carcass weight as this is how they

are paid. In the beef industry producers are paid for fat colour, lean colour, marbling,

pH and other quality parameters as outlined in the discussion on the work of Meat

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Standards Australia (MSA 2010). Game meat processors in Australia do not know

what quality of animal is going to be supplied to fill orders. In Australia a premium

price is paid if animals meet specifications in relation to weight (Hansen 2011). In

NZ killing space is booked ahead of time and meat companies visit producers to

check that animals meet specifications (DINZ 2011). It is apparent that in Australia

there is a lack of whole of supply chain approach to venison quality management, the

adoption of which has achieved a degree of success in both the Australian beef and

lamb industries and the New Zealand venison industry.

Quality assurance (QA) of venison is a key to long term product marketability and

has been identified as a priority component of the long term strategic plan and a key

challenge for the Australian deer industry. Many of the RIRDC funded research

projects completed during 1996-2000 have focused on aspects of QA at various

levels of production and processing, to position the Australian deer industry for long

term viability. The body condition scoring charts (Appendices 1 and 2) are an

example of RIRDC funded projects designed to focus on QA at the production and

processing level. This system provides a common language, which can be used by

producers, processors and marketers to describe carcass characteristics. QA success

is unlikely to be achieved by meat description alone and the task for the deer industry

is to now link production efficiency and processing to consumer acceptance of the

final product. There is now more emphasis on food chain management in most

countries of the world where food is produced in surplus, especially meat. This

project assesses the association between live animal and carcass characteristics and

consumer acceptance of venison by matching eating qualities of venison to body

condition scores and testing these with consumers. This paddock-to-plate approach

will link the outcomes of a series of projects, completed independently of each other,

to provide clear guidelines on carcass characteristics that will guide production

efficiency and value adding on farms and will clearly enhance the credibility,

application and adoption of QA by strengthening links between various sections of

the deer industry.

The need to link carcass production with eating quality has long-term implications

for acceptance of venison as a favoured consumer selection. Hence, definition of the

relationship of BCS with cooking and eating quality will increase opportunities for

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target marketing, which should increase farm profitability and consumer satisfaction

if product consistency is enhanced. However, it is acknowledged that factors such as

methods of slaughter, post-slaughter carcass management and methods of meat

storage can have a significant impact on eating quality of the final product. Texture,

flavour and tenderness are attributes valued by consumers as very important in

relation to the eating quality of meat. Different populations of consumers have

different preferences for these quality attributes, something that affects the market

for all types of meat. However, regardless of the consumer group, the consistency of

meat quality is very important, and the product should be of the same quality every

time it is purchased. In the MSA beef grading system these consumer important

sensory quality attributes have been weighted in an overall score where tenderness

represents 40(%), flavour 20(%), juiciness 10(%) and overall liking 30(%) (MSA

2001).

In addition to the association between BCS and various meat quality parameters,

other techniques employed in this study test the effect of pelvic suspension (tender

stretching) of carcasses for product enhancement, evaluate ageing of venison, and

look at the effect of supplementary feeding of deer pre-slaughter compared with

pasture-fed deer on consumer sensory perception of meat flavour. All of these

factors will be comparatively evaluated for the body condition scores of 2, 3 and 4.

Work undertaken by the beef CRC (Meat Quality) complements the consumer work

done here. Complementary projects relating to condition score and carcass

composition exist for sheep (Glimp et al 1998) and cattle (Apple et al 1999) and aid

in frameworking the proposed study. This project has, however, pioneered this type

of research in relation to venison production. Projects such as those listed above

complement the study as well as providing a model for venison. Tenderstretching or

pelvic suspension of carcasses is becoming increasingly popular in the Australian

beef industry as a result of MSA, and this procedure will be tested with venison to

determine if it is associated with product enhancement.

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2.3.2: Current venison issues

Meat quality studies on deer species are few compared with beef and lamb. In view

of the importance of the deer industry in New Zealand, Europe and the United

Kingdom, it is worthwhile to investigate meat quality to maximise commercial

returns (Daszkiewicz et al 2009; Radder and le Roux 2005).

Deer as a farmed species remain more nervous than other domesticated ruminants

and appear to be more predisposed to stress than many of the more domesticated

species such as cattle and sheep. Their typical first reaction to any external stimuli is

the flight or fight response. This makes deer more difficult to handle when yarding,

loading, transporting and holding in lairage. Facilities need to be designed to hold

deer and keep them in the best condition possible prior to slaughter to optimise meat

quality and reduce the incidence of bruising and high meat pH (Pollard et al 2003;

Hoffman and Wiklund 2006). This is currently an issue for producers in Australia,

where a very small number of abattoirs process deer on a regular basis. Producers are

often faced with the prospect of transporting their animals over large distances of up

to 2,000 km (Joubert 2004) at great expense financially and in relation to animal

well–being, or having to use less cost effective methods of processing such as mobile

slaughter facilities (Shapiro 2010). Despite codes of practice for transport, the long

distances travelled in Australia to take deer for slaughter to one of the few abattoirs

processing deer can result in deaths or downgrading of carcasses from damage

occurring during transit (Joubert 2004). Australian deer producers cited abattoir and

transport costs as well as access to export accredited facilities as reasons for

considering leaving the deer industry (Shapiro 2010). There are very few abattoirs

equipped to hold and process deer, particularly with export accreditation. Currently

the only known abattoirs processing deer are at Bordertown and Strathalbyn in South

Australia (mainly fallow deer), Myrtleford and Wodonga in Victoria and Beaufort

River in Western Australia. As Myrtleford and Beaufort River are the only export

accredited facilities in this group, and the majority of Australia‟s venison is destined

for export, animals from the east coast of Australia are regularly trucked to both of

these facilities (Hansen 2011). In contrast, New Zealand currently has 14 specialty

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venison processors with export accreditation, and distances required to transport deer

to one of these facilities for slaughter are low (Stewart 2011).

Long term sustainability to supply international markets has been frustrated by

failure to meet customer specifications in areas such as meat quality. Part of the

problem with inconsistency of the product comes from inconsistent quality of

animals supplied for processing. This could be aided by use of the BCS system.

Processors are continually encouraged to pay premium prices for stock purchased

from quality assured farms or to reduce prices for those not quality assured. Data

published regularly in the Australian Deer Farming Journal indicates that the quality

of animals processed varies greatly (Tuckwell and Tume 2000).

Current quality issues with venison relate to inconsistency of supply. Producers must

supply quality animals for slaughter and this currently does not appear to be

happening. Animals supplied include bucks/stags, castrates and cull does/hinds, and

the relationship between sex and age to variations in meat quality is unknown. One

area of concern is the number of animals not meeting minimum schedule slaughter

weights or body condition parameters (specifications) as well as varying levels of

bruising during stock handling and transport (Hansen 2004). As noted by Mulley

(1993), there is now a need for the venison production industry to conduct

comparative research into ways of finishing deer prior to slaughter so that seasonal

and gender factors affecting meat quality issues are accounted for in product

consistency.

Cause for concern for each species slaughtered for venison in 1998/1999 and

2000/01 is that more than 50% of carcasses processed weighed less than the ideal

weight range. This results in less farmer return. Statistics for red and rusa deer

indicate that those carcasses heavier than ideal are also discounted. During this time

period only 27.9% of red, 35.2% of fallow and 19.1% of rusa deer fell into the ideal

weight range for their species. The prime weight ranges are red 55-75 kg, fallow >26

kg and rusa 45-55 kg. The obvious effect of improving carcass weight is increased

farmer returns. The principal factor that the industry should consider in an effort to

improve returns to growers is to improve the average quality of stock committed for

processing. Farmer returns may fall unless the average quality (carcass weight and

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BCS) of animals processed improves (Tuckwell 2001a). Unfortunately, this trend

continued until 2007 (Tuckwell 2007). Recent reports from deer processors,

however, indicate that producers currently engaged in strategic alliances have been

able to supply animals of satisfactory carcass weights, although low numbers of

animals available for processing remains an issue (Hansen 2011).

Traceability is another issue for the Australian venison industry. The issue of

traceability has been a key component of quality programs in beef and lamb in

Australia (MSA 2010), and is an integral part of the NZ quality assurance programs

for venison, which were established to meet the exacting standards demanded by

export locations and supermarkets (Barnett 2007). The New Zealand deer industry is

currently investigating and implementing electronic identification to aid traceability

and carcass tracking. The technology allows individual animals to be tracked through

the entire processing chain making feedback possible to producers on the

performance and value of the animals supplied. Initial stages of the project will trace

the live animal through to the venison in cartons, however, it is envisaged that it will

be implemented through to the consumer level (Hickey 2011).

The traditional kill sheet utilised in New Zealand abattoirs will be replaced with a

venison value sheet. Producers will supply details including breeder and sire

identification, weaning dates, weight and live weight gains. The processing plant will

add data relating to dressing and meat yields, value details relating to co-products

such as pizzles and tendons, and customer destinations for primal cuts plus values

per head and per kilogram of venison. Once total value of the animal is established

deductions will be made for fixed processing costs and transport. Producers will then

be provided with comprehensive detail relating to individual animals which will aid

future farm management decisions and potentially improve quality and profitability.

It is envisaged that the traditional New Zealand payment system based on carcass

weight and GR fat depth will be replaced by a value based payment system (Hickey

2011), much the same as the proposed systems for Australian beef and lamb

(Polkinghorne and Thompson 2010). This type of system results in producers

actively contributing to the value chain (Hickey 2011). The Australian venison

industry developed a system known as Venstat, a computer database for processors

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to record similar details to the New Zealand system, but uptake has been slow

(Tuckwell 2001a).

The Australian venison industry remains in an extended slump, with declining

numbers of producers and low returns (McRae et al 2006; Shapiro 2010). Both

venison production and supplies were at a low level, prices received for deer were

also low and export demand had downturned (RIRDC 2007). This positon remains in

2012 in contrast to other red meat industries, such as lamb, where reduced production

has resulted in historically high prices in recent years (McRae et al 2006; Rees 2010).

The future of venison processors relies upon an assured supply of quality animals,

rather than the ad hoc supply of culls (Shapiro 2010), or supplying when the market

is ready but the deer, in terms of condition and live weight, are not (McRae et al

2006). It is acknowledged that the Australian deer industry does not have the same

degree of marketing funds at its disposal as beef, lamb or pork, however, the deer

industry has failed to capitalise on the growth in demand for meat products in recent

years. The industry objective should be to produce venison which consistently meets

and exceeds consumer needs and expectations of a food which is safe, wholesome

and healthy. The product from the beginning has the attributes in keeping with

today‟s consumer preferences (Wright 1993). Without a significant change in supply

chain management, the outlook for the deer industry in Australia is bleak.

The RIRDC commissioned a study to develop a marketing positioning strategy for

Australian venison (Moffat 2005). The study sought consumers of venison in

Australia, both commercial or food service and domestic, to determine their current

perception of the product. The study determined that chefs and the food service

industry in general were responsive to venison, but had issues with the consistency in

quality of the Australian product. Currently the food service sector sources venison

from New Zealand, specifically the Cervena™ brand, which enjoys an international

reputation for quality amongst consumers. The food service sector also identified

limited demand by restaurant clientele and that education of consumers in relation to

the actual flavour and texture of farmed venison, rather than perceived notions of

toughness and gaminess, may be a factor in rectifying this situation (Moffat 2005).

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A study by Cox et al (2006) identified a number of key issues associated with the

Australian venison industry. They included declining economic viability, high

infrastructure and slaughter charges, low viable producer numbers and low deer

prices. Producers also agree with the need for the establishment of a successful

domestic market (Shapiro 2011). Lack of consumer awareness is compounded by the

lack of a venison marketing plan. Underutilisation of whole deer carcasses especially

in relation to secondary or less valued cuts and by-products is an issue. Lack of

suitable product specifications, despite the existence of the AUS-MEAT venison

language and descriptions, continues to hamper quality assurance efforts. No

consistently applied carcass or cut grading system and competition from New

Zealand for the high quality end of the food service market, where top Australian

chefs regard New Zealand venison‟s consistency and quality as higher than that of

Australian venison, are impediments to producers. Australian chefs interviewed by

Moffat (2005) stated that meat grading is very important and there is a lack of

consistency in Australian venison. Cervena™ was seen as a credible brand due to

strict grading. This led to the development of a strategic plan designed to develop an

advanced market focus for venison producers and processors that repositions venison

in the broader red meat market and provides an acceptable price for consumers that

ensures adequate returns within the supply chain (Cox et al 2006).

The venison industry in Australia is plagued by consumer misconception regarding

the flavour profile and tenderness of the product. Traditionally, venison was not

farmed, rather hunted, particularly during game season in Europe and the United

States. Meat from male animals during this rutting or breeding period tended to be

very strong, livery and gamey in flavour and generally lacked tenderness. These

quality attributes resulted in the meat being slow cooked, with heavy, highly

flavoured sauces to mask the strong flavour and limited its consumption to the

traditional winter period, which reinforced seasonal availability. This type of heavy

cuisine does not appeal to younger, wealthy, health conscious and time poor

consumers (Loza 2001). Modern consumers lacking eating experience with venison

tend to believe this is true of farmed venison. The image of venison as a strong

gamey meat is not in line with the majority of the potential market, nor is it in line

with the actual flavour and tenderness profile of correctly prepared farmed venison.

Sensory panels conducted by Moffat (2005) found that consumers rated venison as

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tender, delicately flavoured and fine textured. Once consumers are educated in

relation to flavour attributes and methods of cooking, and availability (Hansen 2004)

and price issues relating to the domestic purchase of venison are addressed, the

potential for favourable feedback on the health features of this meat will be enhanced

(Moffat 2005). The industry needs to be able to deliver venison of consistent quality

and at a reasonable price in order to promote venison as a healthy, premium source

of red meat. Growing demand for venison will need to be supported by all industry

stakeholders to achieve growth in the Australian industry rather than growth in the

importation of New Zealand product (Moffat 2005).

The Australian venison industry has numerous strengths which may be drawn out

and built upon to bring about change, and there is acceptance within the industry for

the need to change. Venison, as a product, is well positioned in the food service

sector and is perceived as a premium product. The Australian industry, by increasing

the quality and consistency of supply, can position itself within this market and

compete with current importation of New Zealand venison. The industry has failed

previously to supply consistent satisfaction to the food service sector in terms of

quality and price, thereby impeding increased usage (RIRDC 2007), while the New

Zealand venison industry has a reputation for delivering consistent, high quality

product (Cox et al 2006). The current success of the New Zealand industry has been

attributed to the improvement of marketing structures and partnerships, market

diversification and development of products to meet changing consumer

requirements, a reputation for quality and trusted branding, and the increase in world

commodity prices (Moffat 2011). Venison is available in New Zealand in

supermarkets around the country, allowing more consumer access, along with

provision of cooking demonstrations and active marketing campaigns (Griffiths et al

2009). Venison is also highly attractive to consumers, once the issue of a lack of

awareness is overcome, and it fits well within current consumer trends for healthy

eating. Venison outscored beef in terms of eating quality with female panellists

(Moffatt 2005). The attractiveness of the product and consumer education are factors

that the industry can capitalise upon to increase demand. This demand, however,

needs to be supported by supply and funds for education and marketing, which are

currently lacking (RIRDC 2007). Demand continues to improve for healthy,

naturally raised meat such as venison, with people seeking low fat premium quality

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and tasty food. Venison‟s nutritional profile as the healthiest red meat is a core

component of its premium market positioning (Moffat 2011).

2.3.3: Strategic industry alliances

Venison can be promoted more effectively with a market focused approach where

consumers are identified and the marketing program directed to the appropriate target

market (Cox et al 2006). The establishment of market focused venison supply chain

alliances is viewed as the best solution to the current problems facing the Australian

venison industry (RIRDC 2007). Cox et al (2006) identified this approach as being

an efficient and effective strategic option for the Australian venison industry to meet

its current challenges. The current commodity system involves the participants

focusing on their own production framework without knowledge of other operations

of the supply chain. The market focused alliance system offers a whole of industry,

or paddock-to-plate, approach to participants. The system identifies the target

consumer value requirements and communicates these to different participants within

the production chain. This results in a shift from production focus to consumer focus.

Consumer issues are of increasing importance to the meat industry (De Smet 2011)

in all sectors from producers through to retailers and food service. The alliances have

a clear focus on delivering value to the target consumer. The aim will be to

determine what the consumer wants and to deliver the desired product, thereby

increasing product demand. A typical alliance would include producers delivering

deer at appropriate specifications, processors facilitating the slaughter of deer and

monitoring production to meet specifications as well as implementing grading

systems, wholesalers delivering specified product, and retailers and food service

supplying product to the target consumer (Cox et al 2006). The concept of strategic

alliances is not a new one for the Australian venison industry, and was recommended

by Tuckwell (2001a) to improve consumer confidence and industry sustainability.

The New Zealand industry also supports a whole of supply chain approach such as

the strategic alliance system proposed in Australia (Moffat 2011). The strategic

alliance approach allows increased connection with food producers by consumers to

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provide a higher degree of certainty about the origin, method of production and

ability to supply (Moffat 2011). Like the Australian industry, the New Zealand

venison industry uses a five year industry strategic intents program to guide industry

development, with the current program in place for 2009-2014. The current NZ

program aims to improve linkages between producers and the market as suggested to

Australian producers by RIRDC in 2007. Improving linkages has the potential to

result in the supply chain providing consumers with what they want, when they want

it, and receiving an adequate return for industry stakeholders. The New Zealand

venison industry has an enviable reputation for innovation and market

responsiveness (Griffiths et al 2009).

A number of supply chain alliances have been established in Australia since the

commencement of the latest five year plan and funding from RIRDC in 2006. To

date they have had limited success, but it is believed that necessity may see more

industry participants becoming involved in alliances and the industry may need to

further this concept in order to survive. Processors have reported improvement in

carcass weights with increases in schedule prices since the alliance program

commenced, however, the ability of producers to supply sufficient numbers of

animals remains an issue (Hansen 2011).

Despite the bleak outlook for the Australian deer industry, the New Zealand deer

industry demonstrates that good profits can still be achieved with the farming and

processing of deer, but it is important that all industry participants along the entire

supply chain are able to maximise and manage various CCP impacts on the supply of

consistent high quality venison to target markets (Shapiro 2010). One issue that is of

concern at the production level is the apparent lack of acknowledgment by producers

of the quality issues that are preventing the establishment of good venison markets

both domestically and internationally. A survey conducted by Shapiro (2010)

indicated that producers fail to identify poor quality as a factor impeding industry

success, when work by Cox et al (2006) indicated that this is a fundamental problem

with the current Australian venison supply. A number of producers, when questioned

about areas of research that they felt needed to be undertaken, responded with „no

more research and development was required‟ and there was a need for a „reduction

of the game flavour of venison‟ (Shapiro 2010). Both of these comments are of

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concern for an industry in crisis. It has been demonstrated by Moffat (2005) that

farmed venison has a mild flavour that is not regarded by consumers as gamey,

although it was perceived to be prior to sampling, and that RIRDC (2007) have

identified that significant research results are available to producers but uptake

appears to be limited.

Producers and processors of Australian venison need to focus on the development of

quality and consistency in their product, and then develop relationships with

consumers. No single strategy will secure the growth of the Australian venison

industry, and all stakeholders in the supply chain will need to work together and be

responsive to the market to achieve success (Moffat 2005). The venison alliance

projects offer hope that a cooperative supply chain approach will aid the ailing

industry (Tuckwell 2007).

The aim of this study is to characterise the meat quality attributes of deer carcasses

for body condition scores 2, 3 and 4 (commercial grades) in order to increase

consumer confidence, and consistency and quality of venison supply. The research

outcomes will result in a guide for industry that links body condition score to meat

quality, in particular, eating quality.

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Chapter Three

General materials and methods

Chapter 3 General materials and methods 76

3.1: Research environment and practices 77 3.1.1: University of Western Sydney deer research facilities 77 3.1.2: UWS fallow deer handling facilities 78 3.1.3: UWS abattoir facilities 80 3.1.4: Commercial abattoir description 81 3.1.5: UWS food processing facilities 82 3.1.6: UWS sensory evaluation and analysis facilities 82 3.1.7: Livestock and management 83

3.2: Meat quality analysis and procedures 85 3.2.1: pH 85 3.2.2: Intramuscular fat 85 3.2.3: Shear force/instrumental tenderness 86 3.2.4: Colour 87 3.2.5: Moisture 88 3.2.6: Freeze/thaw drip loss/purge 88 3.2.7: Carcass core body temperature 88

3.3: Measurements of body condition score 89 3.3.1: Kidney fat index 89 3.3.2: Carcass and fat depth measurements 91

3.4 : Sensory evaluation and analysis 94 3.4.1: Experimental design 94 3.4.2: Cooking and preparation technique 95

3.5: Statistical analysis 96

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3.1: Research environment and practices

3.1.1: University of Western Sydney deer research facilities

The University of Western Sydney Deer Research Unit, situated on the Hawkesbury

campus, consists of approximately 10 hectares divided by a road running north to

south (Plate 3.1). The western side of Campus Drive consists of four large paddocks.

These paddocks are primarily used for the production of red deer. The western side

of the unit also houses an abattoir facility, accredited for the slaughter of animals for

human consumption and described later in the chapter.

Plate 3.1 : Aerial image of the Deer Research Unit at UWS Hawkesbury Campus

(Image courtesy of Google Earth, imagery date 1/1/2009, 33˚37’00.31” S, 150˚45’20.87” E, elevation 26m)

The eastern side of the road consists of six ¼ Ha paddocks, plus six paddocks of

varying size. Each ¼ Ha paddock joins a common laneway to facilitate the

movement of stock to the handling shed or abattoir (Plate 3.2). These paddocks are

primarily used for the production of fallow deer. All paddocks contain self-filling

(float valve type) semi-circular plastic or concrete water troughs serviced by potable

water.

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All paddocks provide shade and several can be irrigated. The paddocks are pasture

improved by oversowing ryegrass, clover and oats into the predominately kikuyu

pasture. Animals were supplemented on lucerne hay and barley grain during periods

of pasture shortfall.

Plate 3.2 : Diagram of the UWS Deer Research Unit located at the Hawkesbury

Campus of the University of Western Sydney (Flesch 2001).

3.1.2: UWS fallow deer handling facilities

Deer were mustered on foot via a laneway 12 feet in width, through a large sliding

wooden door (Plate 3.3) into the handling shed (Plate 3.4) consisting of four main

rooms of diminishing size, a race with rope operated guillotine-type dividers, and a

drop-floor handling cradle.

Plate 3.3 : Entrance to deer handling shed used in this study.

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Plate 3.4 : Deer handling shed at UWS.

The custom built cradle is of steel construction with a sliding door at the rear and

hinged door at the front allowing access to either end of the restrained animal (Plate

3.5). An adjustable back press was included to restrict the movement of animals

whilst involved in experimental procedures, and to minimise the chance of injury to

the animal handler. The cradle is seated on two 250 kg load bars, attached to

Ruddweigh scales (Ruddweigh Pty Ltd, Guyra, NSW, Australia) and digital readout.

Deer were weighed to the nearest 0.5 kg.

Plate 3.5 : Deer handling cradle used in this study.

The handling shed has thick concrete exterior walls and a concrete floor covered with

10-15 cm of coarse hardwood sawdust. The dividing walls and doors are all of

wooden construction with steel frames, and are 2.25 m high (Plate 3.6). Four

fluorescent lights hang from the high ceilings in the shed, as well as one over the

deer handling cradle and another over the second pen from the door. Varying

amounts of natural light also enter the shed via two large skylights located over the

start of the race and over the entry pen.

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Plate 3.6 : Mezzanine view of deer in the handling shed at UWS.

Animals were slaughtered in this facility and transferred to the abattoir within 30

minutes of slaughter. The animals are habituated to restraint in the facility prior to

slaughter to reduce stress, and no transport is required. Captive bolt stunning and

thoracic stick exsanguination within three seconds was performed as described by

Mulley et al (2010). Animals were fasted for 16 hours prior to slaughter. Body

condition score was estimated on the live animal using palpation techniques as

described by Flesch (2001). Live weight was recorded along with blood loss after

exsanguination.

3.1.3: UWS abattoir facilities

The UWS abattoir (Plate 3.7) is located adjacent to the UWS Deer Research Unit.

Skinning and evisceration were performed with carcasses hanging from a meat rail

(Plate 3.8). The slaughter procedure was approved by the UWS Animal Care and

Ethics Committee (ARP 00.009). The neck was severed at the atlanto-occipital

articulation. Hot carcass weights were recorded and carcasses then immediately put

in the cool room (±2 °C). The cool room is large enough to hang at least 30 carcasses

(Plate 3.9). At 24 hours post-mortem each carcass was weighed to determine

standard carcass weight. Meat samples removed from each carcass for analysis were

denvered prior to vacuum packaging (Evac, model 218) and freezing

(-21 C).

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Plate 3.7 : Experimental abattoir at UWS.

Plate 3.8 : Scales and meat rail leading to the chiller in the experimental abattoir.

Plate 3.9 : Fallow deer carcasses in the chiller at UWS.

3.1.4: Commercial abattoir description

Meat samples were also sourced from animals commercially slaughtered at four

processing facilities: Mudgee regional abattoir, Mudgee, NSW; Oberon Game Meat

Processor, Oberon, NSW; Jaafar Abattoir, Myrtleford, VIC and General Abattoir

Services, Wodonga, VIC. Animals were transported to these facilities from

commercial farms in Central West NSW. Animals were slaughtered by captive bolt

stunning and thoracic stick exsanguination within three seconds as described by

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Mulley et al (2010). Animals were fasted for 16 hours prior to slaughter. Carcasses

were stored in cool rooms at each facility held at (±2 °C).

3.1.5: UWS food processing facilities

The University of Western Sydney food processing facility (Plate 3.10) is a small

scale food processing and analysis facility. This facility houses equipment and

facilities for the packaging, storage and analysis of samples (Plate 3.11). It is located

at the Hawkesbury campus of UWS within close proximity to the abattoir. This

allows rapid transfer of boned out meat samples to be vacuum packaged and frozen

for analysis.

Plate 3.10 : Food processing facilities at UWS.

Plate 3.11 : Vacuum packaging equipment.

3.1.6: UWS sensory evaluation and analysis facilities

The University of Western Sydney sensory evaluation laboratory is situated within

the food processing facility. It consists of six individual booths (Plate 3.12) serviced

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by a sample preparation area (Plate 3.13). The design of the facility (Plate 3.14) is

consistent with ISO guidelines (2007). During sensory evaluation of venison

samples, these rooms were kept at a constant 22 ºC. The experimental procedure was

approved by the UWS Human Ethics Committee (HEC 03.206).

Plate 3.12 : Individual tasting booth in the sensory evaluation facility at UWS.

Plate 3.13 : Sensory facility preparation area.

Plate 3.14 : Servery side of the individual tasting booths.

3.1.7: Livestock and management

All fallow deer stock (Plate 3.15) involved in this study were derived from one

commercial deer property in Central West NSW, including those slaughtered at the

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commercial abattoir. All stock were ear tagged prior to purchase. Hybrid

Mesopotamian (Dama dama x dama mesopotamica) bucks were differentiated from

hybrid Mesopotamian haviers via tags in each animal‟s right ear. A number of bucks

were castrated prior to six months of age using elasticator rings (Bainbridge green).

Colour coded ear tags (Allflex) were used to identify ¾ hybrids from ⅞ hybrids.

Plate 3.15 : Hybrid fallow deer at UWS.

Red deer stocks (Plate 3.16) were sourced from two commercial deer properties

located in Central West NSW. Red deer were pasture-fed and later transported to

commercial abattoirs at Myrtleford and Wodonga, VIC.

Plate 3.16 : Typical red deer stag at UWS.

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3.2: Meat quality analysis and procedures

Samples of M. Longissimus dorsi taken over 10 ribs along with M. Gluteus medius

were excised and vacuum packaged 24 hours post-slaughter and stored at -21 ºC for

no more than 12 weeks until analysis. Samples were defrosted in a chiller at 5 ºC for

24 hours. All samples were analysed in triplicate, for each of the parameters

measured and the mean value used for statistical analysis (Perry et al 2001a).

3.2.1: pH

The pH of muscles was measured at slaughter (pHi) (approximately 1 h post-mortem)

and then at 24 hours post-mortem to determine the ultimate pH (pHu). For calibration

of the pH equipment, buffers of known pH 7.0 and pH 4.0 (TPS Pty. Ltd., Brisbane,

Australia) at room temperature were used. The measurement was taken using a

scalpel incision made approximately 2.5 cm deep at the 5th/6th rib and inserting a

glass electrode (IJ44, TPS, Ionode Pty. Ltd., Queensland) attached to a portable pH

meter (TPS LC80A pH-mV-TEMP, TPS Pty. Ltd., Brisbane, Queensland) which was

temperature compensated.

3.2.2: Intramuscular fat

Intramuscular fat was analysed using a Soxhlet apparatus and method (ISO Standard

4401-5, 1996). Samples were homogenised using a food processor and then

evaluated. A 10 g sample was analytically weighed (Sartorius Analytic A200S) onto

filter paper (Whatman Ltd) and samples were then transferred to Soxhlet extraction

thimbles (28 x 100 mm, Whatman Ltd) and air oven dried at 100 oC for 24 hours

(AOAC 1990). A measured 190 ml of petroleum spirit (Type II 40-60o C AR) was

added to each pre-dried and weighed Soxhlet boiling flask, and samples were

allowed to extract for at least six hours. Extraction was performed in a Buchi 810

Soxhlet fat extractor (Plate 3.17)

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Plate 3.17 : Buchi apparatus for Soxhlet fat extraction.

Following extraction, Soxhlet flasks were dried to a constant weight at 100 oC before

desiccation and weighing. IM fat percentages were calculated from the change in

sample weight following extraction. All samples were analysed in triplicate.

Precision percentages were within 0.5%.

3.2.3: Shear force/instrumental tenderness

For tenderness testing, epimysial connective tissue was removed from samples. Half

of the remaining portion of the LD samples were cooked in thick walled plastic bags

in a water bath set at a constant temperature of 67 ºC, with the bag opening extending

above the water surface, over 60 minutes. Internal temperature was measured during

and after cooking to 67 ºC, which is equivalent to medium doneness according to the

method described by Shaw (2000). Samples were removed from the water bath and

cooled in an ice slurry and chilled at 4 ºC until equilibrated (Honikel 1998). Warner-

Bratzler shear force of both raw and cooked samples was measured as the average

from 8-10 cylinders of meat 1 cm diameter and 10 cm length cut with the fibre

direction (Plate 3.18) subjected to a crosshead speed of 0.8 mm/s and a trigger force

of 10 g. Contact area was 1 mm and a contact force was 5.0 g. Texture analysis was

measured by means of force vs. time in compression to determine peak force. Muscle

sample cores were sheared at right angles to the fibre axis (Honikel 1998) with a

Warner-Bratzler shear attachment (Plate 3.19) on a Stable Micro Systems TAXT2

Texture Analyser (Surrey, UK). Peak shear force values were measured and

recorded.

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Plate 3.18 : Samples prepared for colour evaluation and shear testing.

Plate 3.19 : Texture/shear analysis.

3.2.4: Colour

Objective colour dimensions (based on CIE tristimulus values: L*, lightness, higher

number indicates lighter colours; a* redness, higher number indicates more redness

and b* yellowness, higher number indicates more yellowness) were assessed using a

Minolta Chromameter (Cr 300, illuminant D65, 10º standard observer; Minolta

Camera Company, Osaka, Japan). The chromameter was calibrated prior to each use

by measuring the standard white tile. The measurements were the average of three

readings over the LD muscle surface after air blooming at 4 C for 60 minutes (Plate

3.20).

Plate 3.20 : Colour measurement using the Minolta chromameter.

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3.2.5: Moisture

Moisture was determined following standard procedures (AOAC 1990). Samples

were homogenised and a 10 g sample analytically weighed into dry, 10 cm diameter,

aluminium moisture dishes. Samples were placed in a 105 C air oven for 24 hours.

Samples were removed and stored in a desiccator until cool. Samples were re-

weighed and moisture calculated as a percentage of the original weight.

3.2.6: Freeze/thaw drip loss/purge

Freeze/thaw drip loss was measured on meat samples in vacuum bags. Samples of

frozen LD muscle were cut into slices approximately 2.5 cm thick and analytically

weighed using an analytical balance (Sartorius Analytic A200S). Samples were

placed into vacuum bags and vacuum sealed using a vacuum packaging machine.

Frozen samples were placed into a 5 ºC environment. After one week, samples were

removed from refrigerated storage and measured for freeze/thaw drip loss (purge)

using the following procedure: (1) the combined weight of muscle and the vacuum

pack was recorded before opening; (2) at opening, any surplus drip on the meat was

removed using a paper towel and the drip-free weight of the meat recorded. The

combined dry bag and drip-free meat weights were subtracted from the unopened

package weight to derive the total drip weight. Drip weight was then expressed as a

percentage of the original weight of meat packed (Honikel 1998).

3.2.7: Carcass core body temperature

A stainless steel probe (Stab Temp/ATC Sensor, TPS Pty. Ltd., Brisbane,

Queensalnd) attached to a TPS LC80A pH-mV-TEMP meter (TPS LC80A pH-mV-

TEMP, TPS Pty. Ltd., Brisbane, Queensland) in the vicinity of the pH probe entry

was used to record the core body temperature of each carcass. Temperatures were

taken at one hour and 24 hours post-slaughter.

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3.3: Measurements of body condition score

3.3.1: Kidney fat index

Following the method described by Riney (1955), kidneys were excised from the

carcass with a pair of forceps after evisceration and chilled at 2 ˚C for 12 hours (Plate

3.21). Once chilled, the adrenal glands were removed and cuts made with a scalpel

held against each kidney and parallel to its longitudinal axis, removing channel fat

not directly associated with the kidney (Plate 3.22). Some studies have reported KFI

measurements taken on one kidney and its fat (Watkins et al 1991), although

discrepancies in kidney weight between sex, age and size of left and right kidneys in

some mammals (Torbit et al 1988; Dauphine 1975) illustrate the need for

decapsulation and weighing of both kidneys and their fat. Each kidney, with and

without attached fat and its capsule of connective tissue (tunica fibrosa), was

weighed ±0.5 gram (Plate 3.23). Plates 3.21 and 3.22 illustrate the extent of fat

trimming before decapsulation. Kidneys were refrigerated and weighed on a digital

scale within 24 to 48 hours post-mortem. The total difference in weight, which

represented the fat and connective tissue from both kidneys, was divided by the

combined weight of both kidneys without fat or connective tissue. The quotient

multiplied by 100/1 gave the kidney fat index as a percent (Flesch 2001).

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Plate 3.21 : Excised kidneys with channel fat removed (Flesch 2001).

Plate 3.22 : Kidneys trimmed prior to decapsulation (Flesch 2001).

Plate 3.23 : Kidneys prepared and denuded as described by Riney (1955).

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3.3.2: Carcass and fat depth measurements

Several measurements were taken from both live animals and carcasses according to

the body condition scoring system for fallow deer developed by Flesch (2001).

Measurements were made ante- and post-mortem.

3.3.2.1 Live animal measurements

Live deer were palpated whilst restrained in a drop-floor, handling cradle to

determine fat coverage, and allocated a body condition score according to the method

described by Flesch (2001). Variations in subcutaneous fat depth were easily

detectable along the spine, rump and brisket. Musculature and body shape were also

used as determinants of body condition, in conjunction with palpation. To a lesser

extent, observations of the perineum also served as a guide to fat depth, which was

particularly prominent with overly fat animals (Plate 3.24).

Plate 3.24 : Deer in handling cradle for live palpation to estimate BCS (Flesch 2001).

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3.3.2.2 Carcass measurements

Four areas of subcutaneous fat depth were measured on fallow deer carcasses as

described by Flesch (2001). Plates 3.25 to 3.28 illustrate the location that incisions

were made to take these measurements. An incision was made through the fat until

muscle tissue was located, and fat depth was measured with a Hennessy probe to the

nearest millimetre as described by (Flesch 2001) (Appendix 1).

Fat coverage on the foreleg was measured approximately halfway between the elbow

joint and shoulder (Plate 3.25).

Plate 3.25 : Forequarter fat measurement area (Flesch 2001).

Back fat thickness was also determined with a Hennessy probe, from an incision

made perpendicular to the backbone at the last sacral vertebra where fat depth was

measured at the thickest point in millimetres (Plate 3.26).

Plate 3.26 : Loin fat measurement area (Flesch 2001).

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Depth of rump fat was measured from an incision cut at a 45o angle from the spine,

starting from the base of the tail and proceeding anteriorly across the rump (Plate

2.27), as described by Riney (1955).

Plate 3.27 : Rump fat measurement area (Flesch 2001).

Brisket fat was measured at the thickest point from an incision made along the

sternum parallel to the longitudinal axis of the carcass (Plate 3.28).

Plate 3.28 : Brisket fat measurement area (Flesch 2001).

3.3.2.3 GR depth

Red deer body condition score was measured using live animal assessments as

described above for fallow deer using the method of Audige et al (1998). Post-

mortem assessment was made using fat depth at the GR site over the 12th rib at a

point vertically down from the tuber coxae (hip bone), 16 cm out from the back bone

with a Hennessy probe at the time of weighing (Purchas et al 2010) (Appendix 2, 3).

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3.4 : Sensory evaluation and analysis

3.4.1: Experimental design

Descriptive and quantitative consumer preference (affective) sensory testing was

undertaken with 42 naive panellists (Meilgaard et al 2007) who were recruited via

newspaper advertising and email. All procedures for recruitment of panellists and

testing of samples were approved by the Human Ethics Committee of UWS (number

HEC 03-206). There was an even distribution of male and female participants, and a

balanced age distribution from the target market, being 25 to 55 years of age.

Consumers were screened to determine if they were eaters of red meat and were

willing to try venison or were current venison consumers, and to ensure they

preferred meat cooked to medium doneness. Participants who smoked were asked to

refrain from smoking one hour prior to and during the sessions. Familiarisation and

training sessions were undertaken as recommended by ISO (1993) and as described

by AMSA (1995) to assist in identifying quality attributes for venison such as liver

and game flavours, colour, tenderness, juiciness and use of the survey tool.

Panellists were presented with a sample identified by a random three digit code and

answered questions on the descriptive test by indicating on an 11 cm unstructured

line scale (where 0=low intensity and 11=high intensity) how they rated the sample

for flavour, colour, juiciness, tenderness and overall liking (Appendix 4). Samples

were presented on white plates in randomised order. Up to six samples were tasted at

each session and panellists attended four sessions to complete the work in order to

avoid palate fatigue. Each session lasted 30 to 45 minutes with a 15 minute break

given halfway through each session. Panellists were seated in individual isolation

booths with a drinking cup of water (90%) and apple juice (10%) to cleanse the

palate between tastes. Sessions were conducted mid-morning and early afternoon.

Venison samples were examined for microbial safety prior to and after presentation

to panellists (Hutchison et al 2010).

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3.4.2: Cooking and preparation technique

Meat samples were stored frozen at -21 ºC, for no more than 12 weeks, and then

thawed in a chiller at ±4 C 24 hours prior to cooking. Samples were denvered of

silverskin (epimysial connective tissue). Samples of M. Gluteus medius were placed

in vacuum packages and immersed in a water bath set at 67 ºC for approximately 60

minutes to reach an internal temperature of 67 C (AMSA, 1995; Wiklund et al

1997a), which has previously been shown to produce a product which remains

palatable and safe for consumption (Rodbotten et al 2004). Both the water bath and

sample were monitored closely for temperature levels during the cooking process.

When cooked, samples were removed from the water bath and immediately cut into

5 mm thick slices (Plate 3.29). These samples were placed onto a white plate labelled

with a random three digit code and presented immediately to panellists for

assessment (Plate 3.30). Each panellist received their samples in random order to

avoid collusion with other panellists during the assessment process (Plate 3.31).

Plate 3.29 : Venison samples prepared for serving.

Plate 3.30 : Venison samples presented to panellists.

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Plate 3.31 : Panellists assessing venison samples.

3.5: Statistical analysis

Meat quality data and data for the various sensory parameters evaluated were

analysed using statistical software SPSS 11.5, with analysis of variance using the

GLM procedure. Treatment means were separated using Ryan‟s Q test (SPSS 2002).

The data for studies on pelvic suspension were analysed by residual maximum

likelihood (Patterson and Thompson 1971) with the random effects given by reading

within muscle within animal, and the fixed effects by hanging treatment, muscle and

their interaction using the statistical package GenStat (2002). The data from

experiments on freeze/thaw drip loss were analysed by analysis of variance, fitting

slaughter data, hanging treatment and their interaction with the animal as a blocking

factor for the meat quality data using the statistical package GenStat (2002).

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Chapter Four

Relationship between body condition score and

meat quality parameters of venison

Cross section of fallow deer venison loin of BCS 5 (Flesch 2001)

Chapter 4 Relationship between body condition score and meat quality parameters of venison .............................................................................................. 97

4.1: Introduction .................................................................................................... 98

4.2: Materials and methods ................................................................................. 117 4.2.1: Fallow bucks of BCS 2 to 3 ................................................................... 117 4.2.2: Fallow does of BCS 2, 3 and 4 .............................................................. 117 4.2.3: Fallow bucks and haviers (castrated bucks) ........................................... 118 4.2.4: Red deer stags with BCS of 2, 3 and 4 .................................................. 118

4.3: Results ........................................................................................................... 120 4.3.1: Fallow bucks of BCS 2 to 3 ................................................................... 120 4.3.2: Fallow does of BCS 2, 3 and 4. ............................................................. 121 4.3.3: Fallow bucks and haviers ....................................................................... 123 4.3.4: Red deer stags with BCS of 2, 3 and 4 .................................................. 125

4.4: Discussion ..................................................................................................... 127 4.4.1: BCS and live weight .............................................................................. 127 4.4.2: Intramuscular fat .................................................................................... 128 4.4.3: Shear force ............................................................................................. 129 4.4.4: Freeze-thaw/purge .................................................................................. 132 4.4.5: Colour .................................................................................................... 133

4.5: Conclusions ................................................................................................... 135

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4.1: Introduction

Body condition scoring (BCS) is a non-invasive technique that has been established

in numerous animal species to determine general health status and reproductive

capabilities in both farmed and wild populations (Flesch 2001). It is a subjective

measure used to determine the condition or fat cover of an animal relative to its body

size (Evans 1978). The concept is based on the assumption that a particular fat depot

is related to reserves of body fat in the animal in a predictive way (Finger et al 1981).

The technique involves palpation of the live animal to determine the thickness of the

fat cover at various depots such as the rump, loin, brisket and perineum. Higher body

condition scores will have higher fat thicknesses.

There are a number of subjective and objective systems in use internationally as

predictors of body fat in live animals. These include various species specific BCS

systems, GR soft tissue and fat depth at the 12th rib (Hopkins 2010, 2011; Purchas et

al 2010), P8 fat depth over the rump (Pethick et al 2011), ultrasonic measurement of

the thickness of rump fat (MAXFAT) (Cook et al 2010), chest girth measurements

(Riney 1955), fat depth over the M.longissimus thorasis et lumborum (USFatC), dual

energy x-ray absorptiometry (DXA) (Dunshea et al 2007; Hopkins et al 2007), CT

scanning (Asher et al 2011) and video image analysis (VIAScan) (Jopson et al 2005;

Rius-Vilarrasa et al 2007; Hopkins 2010, 2011). Many of these techniques are used

either in isolation or combined to allow reliable estimation of body fat. Animals

destined for slaughter may also undergo post-mortem measures of various fat

indices, such as kidney fat index (KFI) and subcutaneous fat depths, to confirm BCS.

Estimations of BCS in live animals are only as reliable as the trained assessor

conducting the scoring and may be combined with other techniques such as

ultrasonography to enhance accuracy. Once trained and practised, an assessor may

quickly and accurately assign a BCS to a production animal (Phythian et al 2012) in

a handling cradle or free standing in a pen with a minimum of distress (Flesch 2001).

Recent studies in dairy cattle have examined the potential of digital imaging as a

method of automating BCS assessment (Bewley et al 2008; Azzaro et al 2011).

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The body condition of an animal is reflective of its nutritional status. It is a technique

that is fundamental to successful farming and reproductive performance of

ruminants, and also in establishing relationships between animal populations and

their habitats in wild ruminant populations (Torbit el al 1988). In farmed ruminants,

live weight may also reflect nutritional status and possible meat yield, however, it

does not account for variation in genotype within the same species, where some

animals may have larger body frames or musculature than another animal of the

same weight.

Estimation of body condition score has been reported for a number of wild

populations of ungulates in an attempt to relate body fat indices to animal condition,

population density and environment (Flesch 2001). In wild populations, only visual

assessment is generally possible (Riney 1955; Watson 1971) and accuracy is

hampered by seasonal variation in coat thickness and the flight distance of the wild

ungulates. Therefore, body condition scoring of wild ungulates has usually

necessitated post-mortem assessment on representative animals from a given

population. Post-mortem measures of kidney fat and fat indices, such as

subcutaneous fat measures, have been assessed in wild populations and the

techniques transferred and implemented in domestic ruminants (Flesch 2001). The

techniques have been documented for free ranging red deer (Riney 1955) and wild

populations of mule deer (Finger et al 1981) and impala (Anderson 1965).

Relationships between animal condition and fat indices have been documented in a

number of wild ungulate populations, namely white-tailed deer (Robbins et al 1974;

Kie et al 1983; Brown et al 1995); pronghorn (Depperschmidt et al 1987), mule deer

(Torbit et al 1988; Tollefson et al 2010;); elk (Greer 1968; Hunt 1979; Cook et al

2001; Piasecke and Bender 2009); caribou (Dauphine 1975; Chan McLeod et al

1999; Couturier et al 2009); moose (Testa and Adams 1998; DelGiudice et al 2011);

muskoxen (Adamczewski et al 1995); reedbuck (Taylor et al 2005); and impala

(Gaidet and Gaillard 2008). A recent study by Bishop et al (2009) with free ranging

mule deer also examined the potential for evaluating body condition using serum

thyroid hormone concentration in blood samples. The study determined that BCS

should be used whenever possible, although blood chemistry can also be a reasonable

predictor of body condition in wild ungulate populations (Bishop et al 2009). A

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number of studies have been conducted on blood metabolites and their relationship

with body condition and nutritional adequacy (Russel et al 1967; Annison 1960;

Annison et al 1984). The utilisation of these techniques is limited commercially by

the invasive nature and extensive animal handling required in the collection of blood

samples.

The majority of farmed ruminant species have been studied in relation to body

condition, and scoring systems have been developed as an aid for producers when

assessing nutritional status and reproductive performance. Studies have been

conducted in dairy cattle (Garnsworthy and Jones, 1987; Edmonson et al 1989;

Gregory et al 1998; Busato et al 2002; Al Ibrahim et al 2010; Dewhurst et al 2010;

Azzaro et al 2011); beef cattle (Jonhson et al 1972; Lowman et al 1976; Gresham et

al 1986; Nicholson and Sayers 1987; Bullock et al 1991; Perry and Fox 1996;

Markusfeld et al 1997; Dixon et al 2011); sheep (Jefferies 1961; Russel et al 1969;

Pollott and Kilkenny 1976; Butterfield et al 1983; Hopkins et al 1995b; Esmailizadeh

et al 2009; Herrera et al 2010; Maurya et al 2009, 2010; McGregor 2010; Kenyon et

al 2004, 2011); goats (Mitchell, 1986; May et al 1995; Barbosa et al 2009; Rivas-

Munoz et al 2010; Serin et al 2010; Agga et al 2011; Mendizabal et al 2011); red

deer (Kay et al 1981; Audige et al 1998, Hansen 2000); and fallow deer (Flesch

2001). Other production species have also been examined including pigs (Elsley et al

1964; Matousek et al 2011), poultry (Gregory and Robins 1998) and horses

(Henneke 1985; Dugdale et al 2011). BCS has also been used for evaluating the

condition of animals prior to determining their suitability for live export (Gaden et al

2005).

BCS may also be used as a guide for producers and processors when attempting to

achieve optimal slaughter condition in production animals. Currently, live weight is

the most commonly used parameter for determining slaughter suitability. Australia

has adopted the GR fat depth measurement technique, with slaughter animals

described by weight and fat level, however, greater scrutiny of the accuracy and

precision of such measures is needed to make them truly valued and useful

throughout the marketing chain (Hopkins 2011). There are discrepancies in findings

on the relationship of live weight to BCS. Live weight does not take into account

differences between breeds or genotypes within a species. It is possible that two

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animals may be identical slaughter weights and yet have different ratios of

muscle:bone, eye muscle area and yield of saleable cuts. Flesch (2001) found that

BCS was not significantly correlated with live weight when studying fallow deer

with liveweights ranging between 36 and 65 kg. Heavier boned and larger framed

Mesopotamian hybrid fallow deer had lower fat deposition than similar live weight

European fallow deer. Hopkins et al (1996) found that live weight in lambs was a

poor predictor of carcass fat depth at the GR site and LD fat depth. A study on

Angora goats and Merinos in southern Australia found a highly correlated

relationship between BCS and live weight (McGregor 2010), as did Glimp et al

(1998) and Sanson et al (1993) on studies of ewes. Linear relationships were

established for beef cattle for live weight, carcass weight, dressing percentage, eye

muscle area, fat thickness, muscle:bone ratio and yield (Apple et al 1999). Mitchell

et al (1976) found relationships between bodyweight and BCS in free ranging red

deer. Wilson and Audige (1996) examined target setting for BCS and body weights

in red deer, and formulated targets for production minimums and optimums. They

found that bodyweight alone provided a critical and accurate marker for venison

production. However, they also determined that setting targets for growth or BCS

was essential for producers to be able to supply specified product to venison markets.

Body condition indices are also measured post-mortem to validate visual or live

animal palpation assessment (Flesch 2001). BCS is frequently confirmed using three

areas of accumulated fat reserves, i.e. kidney fat index (KFI) (Riney 1955), bone

marrow fat (BMF) and subcutaneous fat (Harris 1945; Riney 1955). Fat reserves

provide a good indication of body condition and are deposited in animals in a pre-

determined sequence: initially in the bone marrow, then around the kidney and other

organs, followed by subcutaneously, and finally intramuscularly (Hammond 1932).

This theory is supported by Harris (1945), Riney (1955) and Jopson et al (1997) who

also examined mobilisation of fat stores during periods of feed deprivation, which

occurs in reverse order to deposition.

KFI is calculated using the ratio of perirenal fat to kidney weight (Flesch 2001). The

weight of the kidney is assumed to be relative to body size and provides the

benchmark from which deposition or mobilisation of fat can be measured (Batchelor

and Clarke 1970). This theory was disputed in a number of studies on seasonal

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variations in weight of kidneys in caribou (Dauphine 1975; Gerhart et al 1996); mule

deer (Torbit et al 1988); and wild sheep (van Vuren and Coblentz 1985). It is

understood that kidneys size decreases in malnourished deer (Torbit et al 1985) and

therefore may not always be an accurate indicator of body condition due to changes

in kidney weight, in animals experiencing, or recovering from, periods of

malnutrition.

KFI has been studied in white tailed deer (Ransom 1965; Finger et al 1981; Johns et

al 1984); mule deer (Anderson et al 1972; Torbit et al 1988); red deer (Riney 1955;

Batcheler and Clarke 1970; Suttie 1983); feral sheep (van Vuren and Coblentz); tahr

(Anderson and Henderson 1961); hares (Flux 1971); elk (Flook 1967); pronghorn

(Bear 1971); and chamois (Perezbarberia et al 1998). It is generally accepted as a

reliable indicator of body fat reserves, although as described previously, there is

decreased predictability in emaciated animals with very low KFI values (Ransom

1965). Suttie (1983) examined the relationship between KFI and BMF as an indicator

of BCS in red deer stags, and determined that KFI was not a reliable measure of total

body fat reserves in very lean animals (below BCS 2) without also examining BMF

and subcutaneous fat. These findings were confirmed in fallow deer (Flesch 2001).

For animals in poor condition, the most reliable indicator of body condition is bone

marrow fat (Riney 1955; Ransom 1965), used in conjunction with KFI or other

indices.

Other indicators of animal condition include animal height and chest girth

measurements. These techniques have been utilised in a number of studies relating

seasonal fluctuations to animal condition (Riney 1955; Weckerley et al 1987;

Houghton et al 1990). These methods of assessment have had limited success in

relation to determining body condition and are more closely correlated with live

weight (Smart et al 1973; Millspaugh and Brundige 1996), with limited application

in assessments on wild deer. The amount of animal handling required to undertake

these assessments in domestic species makes it less applicable in commercial

farming situations where large numbers of animals are being assessed. When live

weight is included in the equation with chest girth and animal height measurements

in beef cows, there is better correlation with body condition (Houghton et al 1990);

when used in isolation, palpation was found to be more accurate (Klosterman et al

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1968; Nelsen et al 1985). Flesch (2001) demonstrated that chest girth in BCS 4

fallow deer was significantly larger than BCS 2 and BCS 3, however the differences

between each score were insignificant. He concluded that they were not correlated

with any other condition indices. Therefore, height:weight ratios and chest girth

relationships were not practical or accurate methods of estimating body condition.

Combining palpation and visual assessment of BCS with other indicators such as

KFI, measures of subcutaneous fat, BMF, live weight and chest girth measurements

increased the accuracy of carcass composition predictions (Kistner et al 1980;

Depperschmidt et al 1987). Estimation of BCS by palpation is a rapid, noninvasive

method and the most common, and potentially accurate, method of assessing BCS

ante-mortem in large numbers of animals (Audige et al 1998). The BCS of breeding

and slaughter stock provides useful insights into management practices and

nutritional status of individual animals. Fatty deposits are only palpable in animals of

good condition, however, prominence of the spine, pelvis, sternum and ribs are used

as indicators of the presence or absence of fat deposits. Body shape and musculature

also form part of the visual and palpable assessment of BCS (Flesch 2001).

Several studies have examined the relationship between BCS or GR fat and tissue

depth with carcass composition and meat yield in sheep (Russel et al 1969; Glimp et

al 1998; Safari et al 2000; Ponnampalam et al 2007); dairy cows (Gresham et al

1986; Gregory et al 1998); beef cattle (Ledger and Hutchison 1962; Charles 1974;

Hinks and Prescott 1974; Faulkner et al 1990; Vieira et al 2007); and goats

(Greenwood et al 2008), however, no links were made to meat quality parameters.

GR fat depths have been identified as the most significant variable in prediction of

percentage yield of saleable cuts in lamb (Hopkins et al 1995b). This finding was

confirmed by Lambe et al (2009), where subcutaneous fat depth was found to

improve predictions of carcass composition and IMF in lamb carcasses.

Confirmation of BCS significantly improved accuracy of estimation when combined

with HCW and fat depth over the eye muscle area. The results indicated that as body

condition or conformation score increases, yield increased (Hopkins et al 1995b).

The predominant method in Australia for predicting meat yield in lamb carcasses is

HCW and tissue depth at the GR site (Hopkins 2008).

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Flesch (2001) developed a BCS system for use with fallow deer. The focus of this

work was establishing the relationship of BCS to reproductive performance and

nutritional status of fallow deer. Prior to the completion of this study, fallow deer

farmers and processors had no uniform methods of assessing animal condition,

predicting saleable meat yield or carcass composition, and therefore, value of a

particular animal. This allowed the potential for disagreement between producers and

processors as to the required condition and value of slaughter stock. At one time, a

processor in Sydney released a pricing schedule with condition grades of 1

(emaciated) to 5 (fat), paying a premium at grade 4 „prime‟ animals, stating that

carcasses from BCS grades 1 and 2 animals had no value. There were no animal or

carcass descriptors included, which gave producers no indication of the parameters

required for determining prime animals (Flesch 2001).

Studies of meat yield and fat content of fallow deer of various ages and sex have

been conducted, however, there have been no relationships established between live

weight and body condition (Mulley 1989; Hogg et al 1993). The GR site has been

used extensively as a predictor of carcass fatness and subsequent meat yield with

sheep (Kirton et al 1995), cattle (Ferrell and Jenkins et al 1984) and goats (May et al

1995). There has been no documented correlation between this measurement and

carcass fat and meat quality with farmed deer. Fisher et al (1998) suggested that

establishing a system whereby animals could be compared regardless of breed effects

within the same species would be useful for the meat industry rather than being

misguided by live weight, and utilised fat classes to accurately predict carcass

composition. Being able to predict meat yields and fat percentages as they relate to

BCS is of importance to processors, and subsequently impacts on prices paid to

producers. Overfat animals require trimming at slaughter, while undernourished

animals supply lower meat yields. The BCS system allows producers to set targets

for the production of animals in the condition required by processors, and be paid a

premium for doing so. By establishing links with BCS to meat quality, the Australian

deer industry may be better able to provide quality assurance to purchasers of

Australian venison. Body condition scoring charts have been produced for Australian

fallow deer (Appendix 1) and red deer (Appendix 2) (Tuckwell et al 2000a; b), and

for red deer in New Zealand (Audige et al 1998) (Appendix 3).

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The BCS system for fallow deer has been designed using 5 grades, starting at BCS 1

(emaciated); BCS 2 (lean); BCS 3 (prime); BCS 4 (fat); and finishing at BCS 5

(overfat) (Tuckwell et al 2000a). Grade 1 animals are normally suffering from

malnutrition, ill health or old age, and have not been used in this study as they

present little value to processors and are not commonly seen on farms. The live

animal and carcass characteristics for the scores used in this study are detailed below.

BCS 2 animals, despite being thin, are more often seen on farms, particularly in

times of feed shortfall or during and immediately after the breeding season or rut.

The wings of the pelvis are prominent and easily palpable, the rump is flat with only

slight tissue coverage, the spine is also easily palpable and the saddle has a slightly

angular appearance (Plate 4.1).

Plate 4.1 : Mature fallow deer doe of BCS 2.

The dorsal appearance (Plate 4.2) of the BCS 2 carcass shows small levels of fat on

the rump, with little or no fat evident over the saddle. The spine and pelvic wings are

prominent.

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Plate 4.2 : Dorsal view of BCS 2 carcass.

The caudal appearance shows some deposition of brisket fat which is not seen in

BCS 1 (Plate 4.3).

Plate 4.3 : Caudal view of BCS 2 carcass.

The cross sectional view of the loin (Plate 4.4) shows full musculature, without the

atrophy that is commonly seen in a BCS 1 carcass, and a thin layer of fat covering

the muscle. Mean subcutaneous fat depths for BCS 2 are rump 2.3 mm (±0.9), loin

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107

1.9 mm (±0.8), brisket 2.3 mm (±1.0) and forequarter 0.6 mm (±0.5). The KFI range

for BCS2 was 23.9-51.5 with a mean of 33.9 (±8) (Flesch 2001).

Plate 4.4 : Cross sectional view of EMA of BCS 2 carcass (Flesch 2001).

Animals of BCS 3 are neither fat nor thin, and do not display prominent areas of fat.

The condition of BSC 3 is recommended as a minimum score for breeding stock in

red (Audige et al 1998) and fallow deer (Flesch et al 2002). The wings of the pelvis

are still palpable but with slight pressure, the spine is palpable but slightly enveloped

in tissue. The body around the spine is more rounded. The rump is still flat although

greater muscle mass is felt with firm pressure (Plate 4.5).

Plate 4.5 : Mature fallow deer buck of BCS 3 (Flesch 2001).

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The dorsal appearance (Plate 4.6) of the BCS 3 carcass shows moderate levels of fat

on the rump, with some fat evident over the saddle and beginning to deposit over the

forequarter. The spine and pelvic wings are no longer prominent.


The caudal appearance shows moderate deposition of brisket fat (Plate 4.7).


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The cross sectional view of the loin (Plate 4.8) shows good musculature, with a layer

of fat covering the now rounded muscle. Mean subcutaneous fat depths for BCS 3

are rump 4.4 mm (±1.6), loin 2.9 mm (±0.7), brisket 4.2 mm (±1.1) and forequarter

1.1 mm (±0.7). The KFI range for BCS 3 was 51.0-97.3 with a mean of 71.2 (±12.6)

(Flesch 2001).


BCS 4 animals (fat) are considered to be in good condition (Plate 4.9). The wings of

the pelvis are rounded and can be palpated under a layer of fat. The spine is

enveloped in fat and felt only with firm pressure. The body is well rounded with no

clear delineations between the torso and pelvis area. The rump area is slightly convex

and has considerable fat coverage. Brisket fat is now visible and easily palpated

(Flesch 2001).

Plate 4.9 : Mature fallow deer bucks of BCS 4 (Flesch 2001).

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110

The dorsal appearance (Plate 4.10) of the BCS 4 carcass shows levels of fat over the

entire length of the carcass with rounded hindquarters. The spine and pelvic wings

are no longer visible.


The caudal appearance shows increased deposition of brisket fat (Plate 4.11).


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The cross sectional view of the loin (Plate 4.12) shows the entire loin area covered

by a thick layer of fat. Mean subcutaneous fat depths for BCS 4 are rump 7.2 mm

(±1.3), loin 4.6 mm (±0.7), brisket 5.5 mm (±0.9) and forequarter 2.2 mm (±0.6). The

KFI range for BCS 4 was 96.5-128.2 with a mean of 115.1 (±19.7) (Flesch 2001).


Animals of BCS 5 were not used in this study. It is difficult to find production

animals in this condition, however, Flesch (2001) states that fallow deer bucks with

abundant feed may obtain BCS 5 over the summer. Processors will apply financial

penalties to producers supplying the abattoir with overfat animals due to the

trimming required, with no significant increase in saleable meat yield over BCS 4

animals.

An Australian BCS chart for red deer (Tuckwell et al 2000b) displays the same five

grades with similar live animal descriptions and photographic examples with GR fat

depth guidelines provided. A copy of the chart may be found in Appendix 2. Plate

4.13 illustrates an example of a mature red stag of BCS 4. Note the brisket fat visible

on the live animal.

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112

Plate 4.13 : Mature red stag of BCS 4.

Carcass fat, including subcutaneous fat depths, increase as BCS increases. Plate 4.14

illustrates an example of fat over the rump of a BCS 4 red stag carcass.

Plate 4.14 : Red stag carcass of BCS 4.

Flesch (2001) recommended that producers use BCS as selection criteria for

slaughter animals in conjunction with live weight. This allowed processors and

producers to avoid discrepancies relating to the criteria associated with the

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113

characteristics of lean, prime and fat carcasses. Venison processors will pay a

premium for what is considered a well muscled carcass requiring minimal fat

trimming within a given weight range. It is difficult, however, to determine the

eating quality of meat by visual assessment of the live animal, carcass or muscle. The

BCS system provides a common language for producers and processors, and links to

meat quality should increase profitability at all sections of the value chain. This study

aims to relate BCS to subsequent meat quality from lean, prime and fat carcasses,

and to determine whether a prime live animal and a prime carcass results in prime

eating quality venison.

Few studies have been conducted on the relationship of BCS to meat quality,

although the nutritional and physical status of deer has been demonstrated to improve

muscle glycogen and pHu post-mortem in reindeer (Wiklund et al 1995; 1996a).

Therefore, producing animals with optimal BCS may be useful in achieving better

pHu values after subjecting animals to normal pre-slaughter stressors. A study of red

deer showed lower pHu in animals with higher GR depths and carcass weights

(Wiklund et al 2010). The thickness and distribution of carcass fat in beef carcasses

affects the relationship between carcass characteristics and post-slaughter processing

conditions in relation to chilling rate, rate of pH fall, sarcomere length and potential

for ageing (Oddy et al 2001). As BCS increases, carcass fat deposition increases. Fat

deposition on a carcass can affect the appearance of meat cuts, reduce evaporative

losses and increase shelf life (Fisher et al 1998), can protect the carcass from

microbial attack, and can alter the cooking and processing qualities of meat (Aberle

2001). Rate of chilling is negatively correlated with carcass weight and back fat

thickness in sheep, whilst lower fat levels can result in fast chilling and cold

shortening, giving rise to an undesirable lack of tenderness (Okeudo and Moss 2005).

Stevenson et al (1992) examined seasonal venison quality variation in red deer stags

pre- and post-rut and found variations in GR depth, with subsequent variations in

IMF, tenderness and colour. Similarly, mean carcass weights and GR depths were

significantly higher pre-rut than post-rut in recent red deer studies (Wiklund et al

2010). Assessment of body condition score in live animals is directly associated with

subcutaneous fat coverage on the carcass, and intramuscular and intermuscular

(seam) fat deposition (Flesch e2001; Flesch et al 2002).

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A major study relating animal body condition and eating quality is the development

of the Meat Standards Australia program (MSA 2010). In terms of meat eating

quality, MSA has revolutionised the way in which beef has been assessed to

guarantee optimal eating quality. The MSA grading system models an eating quality

score for beef using the primary animal and carcass characteristics of Bos indicus

percentage, carcass weight, sex, ossification, marbling scores and pHu. The

secondary characteristics utilised in this model are meat colour, rib fat depth, muscle

texture and firmness, and weight adjusted for maturity along with treatment effects.

The principle behind the MSA grading system is to optimise animal characteristics

and processing variables with preparation at the consumer end to ensure optimal

eating quality. A study by Watson et al (2008) reported that fat depths and meat

marbling scores were positively correlated and formed part of the meat quality score

for beef. Minimum rib fat requirements are in place for beef as it relates to even

chilling in the muscles and the subsequent positive effect on meat quality

(Polkinghorne et al 2008a).

Lambe et al (2008) suggested that in vivo methods, of which BCS is an example, of

assessing carcass and meat quality could result in improved meat quality in lambs

and provide incentive for producers to aid the improvement of meat quality. Live

weights and assessment of body condition are commonly used by producers of lamb

to select live lambs that may produce the best potential carcass characteristics

(Lambe et al 2008), yet little work has been done to quantify the meat quality

characteristics of this assessment.

Flesch (2001) determined that, in terms of animal production, being able to estimate

body condition of individual animals was vitally important for both breeding and

slaughter stock. However, little work has been done on establishing links with body

condition to the subsequent meat quality of slaughter animals. If there is a strong

relationship between BCS and meat quality characteristics, then BCS will not only be

an important tool in assessing the health and productive potential of farmed deer, but

will also assist in quality assurance and product description to enhance marketing

opportunities and consumer confidence. The majority of fallow deer on farms fall

into the BCS 2, 3 and 4 categories (Hansen 2011). With animals of slaughter weight,

the ability of the producer to determine BCS may have an important influence on the

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timing, age and selection of animals for slaughter, with premiums paid for animals in

prime condition (Hansen 2011).

Red meat processors in Australia currently use measures of subcutaneous fat depth

and animal weight to predict lean meat yield. In the Australian sheep meat industry,

Hopkins (2011) suggested that improved predictive accuracy of lean meat yield

could be achieved by use of subjective estimates of subcutaneous fat such as those

used in the BCS system for red and fallow deer. A BCS on a five point scale used in

combination with fat and muscle depth measurements could achieve increased

predictive accuracy. There is evidence that utilisation of loin fat measures and

muscle weight can improve accuracy of lean meat predictions up to 76% (Hopkins

2008) over the reported accuracy of the current VIAScan system of 55% (Hopkins et

al 2004). Pethick et al (2011) concluded that in Australia, the time is right for cost

effective industry measures of prediction of lean meat yield to facilitate clearer price

signals for producers than the currently utilised system of a single point measure of

subcutaneous fat in beef and lamb.

Animals used in the current study included fallow deer bucks, haviers (castrated

males) and does, as well as red deer stags. An experiment with haviers was

conducted in the early stages of the project because at that time a number of

producers were castrating fallow deer buck prior to puberty to control aggressive

behaviours, supply quality venison year round and extend the slaughter season

beyond puberty (12-15 months of age), including the breeding season or rut. During

the rut male animals are likely to lose condition and have fluctuations in testicular

androgen levels, resulting in behavioural changes and increased risk of body damage

caused by fighting (Stevenson et al 1992). The impact of seasonal change is greater

for entire males compared with females and castrated males (Pollock 1975).

Castration has been utilised in livestock production systems for hundreds of years to

manage male aggression and improve meat quality (Field 1971; Seideman et al

1982). The effects of castration on cervids have been limited to effects relating to

growth and carcass composition in fallow deer (Mulley and English 1985; Asher

1986; Mulley 1989; Hogg et al 1990) and red deer (Drew et al 1978; Asher et al

2011), however, none of this work was linked to meat quality. Since the time of

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conducting these experimental trials, producers have ceased the practise of castration

and are now slaughtering non-breeding does during the breeding season.

This chapter describes the meat quality characteristics of venison from red and

fallow deer collected in a series of experiments associated with measured BCS in

animals of different sex.

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4.2: Materials and methods

4.2.1: Fallow bucks of BCS 2 to 3

Thirty one entire fallow deer bucks ranging from 18-24 months old and with BCS

ranging between 2 (n=16) and 3 (n=15) (lean and prime) were slaughtered by captive

bolt stunning and thoracic stick exsanguination within 3 seconds of the stun (Chapter

3) and hung by the Achilles tendon. Carcasses were measured for core body

temperature and muscle pH at 1 and 24 hours post-mortem. BCS was measured ante

-mortem and confirmed with carcass measurements post-mortem. The M.

longissimus dorsi muscles (strip loins) were boned out from each carcass once core

body temperature was less than 7 °C post-slaughter and divided into two sections,

one complying with the specified standard for mid-loin according to AUS-MEAT

(1995) guidelines, and one from the foreloin (cranial) section of the muscle. These

selected cuts were vacuum packaged and frozen at –21 °C until analysed. Samples

were analysed in triplicate for pH, intramuscular fat, colour, shear force, moisture

and freeze-thaw loss and purge. Kidneys were excised for later KFI calculations to

assist confirmation of BCS.

4.2.2: Fallow does of BCS 2, 3 and 4

Twenty four non-pregnant fallow does, approximately 36 months old with a history

of one previous lactation, and of BCS 2 (n=7), 3 (n=7) and 4 (n=10) were

slaughtered using the methods described in 4.2.1. Carcasses were measured for core

body temperature and muscle pH at 1 and 24 hours post-mortem. BCS was measured

ante-mortem and confirmed with carcass measurements post-mortem. The M.

longissimus dorsi muscles (strip loins) were boned out from each carcass once core

body temperature was less than 7 °C post-slaughter. These cuts were vacuum

packaged and frozen at –21 °C until analysed. Samples were analysed in triplicate for

pH, intramuscular fat, colour, shear force, moisture and freeze-thaw loss and purge.

Kidneys were excised for later KFI calculations to assist confirmation of BCS.

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4.2.3: Fallow bucks and haviers (castrated bucks)

Entire (n=31) and castrated (n=l8) fallow bucks ranging from 18-24 months old and

with BCS ranging between 2 (n=29) and 3 (n=20) (lean and prime) were slaughtered

as described in 4.2.1. All carcasses were hung by the Achilles tendon and measured

for core body temperature and muscle pH at 1 and 24 hours post-mortem. The

M.longissimus dorsi LD cut from each animal was divided into three sections,

foreloin (cranial end), mid-loin and hind loin (caudal end) and were vacuum

packaged and frozen at -21 °C for no more than 12 weeks until analysis. Samples

were analysed in triplicate for pH, intramuscular fat, colour, shear force moisture and

freeze-thaw loss and purge.

4.2.4: Red deer stags with BCS of 2, 3 and 4

Rising 2-year-old red deer stags with BCS 2 (n=14), BCS 3 (n=6) and BCS 4 (n=6)

were sourced from farms in the Central West region of NSW at Blayney, NSW (BCS

2) (Plate 4.1) and Neville, NSW (BCSs 3 and 4) (Plate 4.2). Body condition score

was estimated on the live animal using palpation techniques as described by Flesch et

al (2002). Animals were trucked to either Wodonga abattoir (BCS 3 and 4) or

Myrtleford (BCS 2) and held overnight prior to slaughter with ad libitum access to

water. All animals were slaughtered using techniques described in 4.2.1. Skinning

and evisceration were performed with carcasses hanging from a meat rail by the

Achilles tendon. At slaughter the hot carcass weight was recorded, as was pH in

(LD), and core body temperature. Kidneys were excised for later KFI calculations.

While hot, carcasses were split along the spine by bandsaw and hung by the Achilles

tendon (Plate 4.3). At 24 hours post-mortem carcasses were weighed to determine

standard carcass weight. Ulitmate pH and final core body temperature was recorded.

Fat depth measurements were taken at the GR site with a Hennessy probe to confirm

BCS post-mortem. KFI was also calculated to confirm live animal and carcass BCS

assessments.

Chapter Four

119

Plate 4.15 : Red stags of BCS 2.

Plate 4.16 : Red stags of BCS 3 and 4.

Plate 4.17 : Split red stag carcasses of BCS 2 hanging in the chiller at Myrtleford

abattoir.

Three days post-mortem the LD muscle from each of the carcasses was removed.

Samples removed from the carcasses for analysis were placed on marked trays and

vacuum packaged and then frozen at -21 C for no more than 12 weeks until used for

analysis.

Chapter Four

120

4.3: Results

4.3.1: Fallow bucks of BCS 2 to 3

The live weights of the BCS 2 bucks ranged between 39 kg and 57.5 kg giving an

average weight of 47.5 kg (sem 2.16) (Figure 4.1). Dressed carcass weights ranged

from 22.4 kg to 31.6 kg with an average of 26.2 kg (sem 1.48) indicating an average

dressing percentage of 56% (sem 3.28). Body condition scores were confirmed via

measurement of subcutaneous fat depth and KFI. Average fat depth for BCS 2 on the

brisket was 1.9 mm, forequarter 0.4 mm, loin 1 mm and rump 2.2 mm. Average KFI

for BCS 2 was 38.2 (sem 1.2).

The live weights of the BCS 3 bucks ranged between 38 kg and 56 kg giving an

average weight of 47.4 kg (sem 2.90) (Figure 4.1). Dressed weights ranged from 23

kg to 30.8 kg with an average of 26.3 kg (sem 1.60) indicating an average dressing

percentage of 56% (sem 2.09). Body condition scores were confirmed via

measurement of subcutaneous fat depth and KFI. Average fat depth for BCS 3 on the

brisket was 2.5 mm, forequarter 1.3 mm, loin 2.7 mm, rump 5 mm. Average KFI for

BCS 3 was 95.1 (sem 1.3).

Figure 4.1 : Live weights of the fallow bucks of BCS 2 and BCS 3 used in this study.

0.0

10.0

20.0

30.0

40.0

50.0

60.0

1 2 3 4 5 6 7 8 9 10 11 12

L

i

v

e

W

e

i

g

h

t

k

g

Number of animals

BCS 2 Bucks

BCS 3 Bucks

Chapter Four

121

Meat quality parameters and relationships between meat quality parameters and BCS

are shown in Table 4.1. In this experiment, no significant differences were detected

between animals of BCS 2 and BCS 3 in any of the parameters of meat quality, with

the exception of freeze-thaw loss and purge, where BCS 3 samples had significantly

higher purge than BCS 2 (p<0.001).

Table 4.1 : Meat quality attributes of M.longissimus dorsi from fallow bucks of

BCS 2 (n=16) and 3 (n=15).

BCS pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moisture

(%)

IM

Fat

(%)

Freeze

Thaw

loss

(%)

BCS 2 5.41a

(0.17)

5401.5a

(386.0)

2424.9a

(176.3)

20.23a

(0.345)

12.28

(0.32)

0.18a

(0.15)

75.73a

(0.13)

2.85a

(0.21)

11.24a

(0.49)

BCS 3 5.50a

(0.43)

4890.2a

(240.2)

2350.8a

(123.8)

21.33a

(0.57)

11.58a

(0.41)

0.12a

(0.17)

76.00a

(0.19)

2.96a

(0.21)

16.00b

(0.74)

Means and standard error of means (in parenthesis) are shown.

Treatments followed by the same letter in the columns are not significantly different

(p<0.05).

4.3.2: Fallow does of BCS 2, 3 and 4.

The live weights of the BCS 2 does ranged between 37 kg and 42 kg giving an

average weight of 39.1 kg (sem 1.79) (Figure 4.2). Dressed weights ranged from

22.9 kg to 28.5 kg with an average of 25.1 kg (sem 1.09) indicating an average

dressing percentage of 64%. Average fat depth for BCS 2 on the brisket was 2.8

mm, forequarter 0 mm, loin 0.4 mm, rump 3.4 mm. Average KFI for BCS 2 was 49.6

(sem 1.2).

The live weights of the BCS 3 does ranged between 42.5 kg and 44.5 kg giving an


25.1 kg to 29 kg with an average of 27.6 kg (sem 1.82) indicating an average

dressing percentage of 63%. Average fat depth for BCS 3 on the brisket was 6 mm,

forequarter 2.5 mm, loin 2.5 mm, rump 7 mm. The average KFI was 97.1 (sem 1.1).

Chapter Four

122

The live weights of the BCS 4 does ranged between 41.5 kg and 50 kg giving an


28.3 kg to 33 kg with an average of 28.7 kg (sem 2.20) indicating an average

dressing percentage of 64%. The fat depths for BCS 4 on the brisket was 8.5 mm,

forequarter 4.1 mm, loin 3.5 mm and rump 9 mm. The average KFI for BCS 4 was

137.4 (sem 1.1).

Figure 4.2 : Live weights of the fallow does of BCS 2, 3 and 4 used in this study.

For fallow deer does, there were significant differences between BCS for IMF (BCS

2-3, F1,16 = 32.713, p<0.001); (BCS 3-4, F2,18 = 7.988, p<0.01), with IMF increasing

as BCS increased., and colour „a‟ (redness) (F1,16 = 4.414, p<0.05), with redness

values at BCS 4 being lower than BCS 2 or BCS 3. There were significant

differences between BCS for tenderness (cooked shear force values) (F2,18=3.984,

p<0.05), with meat from BCS 4 carcasses being more tender than meat from BCS 2

and BCS 3 carcasses (Table 4.2).

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10

L

i

v

e

w

e

i

g

h

t

k

g

Number of Animals

BCS 2

BCS 3

BCS 4

Chapter Four

123

Table 4.2 : Meat quality attributes of M. longissimus dorsi from fallow does of

BCS 2 (n=7), BCS 3 (n=7) and BCS 4 (n=10).

BCS pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moisture

(%)

IM

Fat

(%)

Freeze

Thaw

loss

(%)

BCS

2

5.48a

(0.05)

4538.9a

(686.1)

2640.1a

(394.8)

20.91a

(0.31)

11.68a

(0.44)

2.43a

(0.29)

75.79a

(0.43)

1.63a

(0.12)

18.02a

(1.42)

BCS

3

5.47a

(0.06)

4476.6a

(452.3)

2629.5a

(194.2)

20.91a

(0.46)

11.67a

(0.27)

2.84a

(0.31)

75.69a

(0.42)

2.69b

(0.09)

19.44a

(0.99)

BCS

4

5.49a

(0.03)

3610.6b

(224.0)

2598.9a

(191.3)

21.69a

(0.76)

10.99b

(0.22)

2.97a

(0.28)

75.41a

(0.21)

3.79c

(0.65)

19.11a

(1.42)

Means and standard error of means (in parenthesis) are shown. Treatments followed

by the same letter in the columns are not significantly different (p<0.05).

4.3.3: Fallow bucks and haviers

Live weights, dressing percentages, BCS measurements and KFI results for fallow

deer bucks are in section 4.3.1.

The live weight of the BCS 2 haviers ranged between 40 kg and 52.5 kg giving an

average weight of 46.7 kg (figure 4.3). Dressed weights ranged from 23.5 kg to 31.9

kg with an average of 26.2 kg (sem 1.20) indicating an average dressing percentage

of 56%. Body condition scores were confirmed via measurement of subcutaneous fat

depth and KFI. Average fat depth for BCS 2 on the brisket was 2.4 mm, forequarter

0.4 mm, loin 1.4 mm, rump 3 mm. Average KFI for BCS 2 was 33.3 (sem 1.30).

The live weight of the BCS 3 haviers ranged between 41.5 kg and 52 kg giving an

average weight of 46.6 kg (Figure 4.3). Dressed weights ranged from 22.5 kg to 32.5

kg with an average of 26.6 kg indicating an average dressing percentage of 57%.

Body condition scores were confirmed via measurement of subcutaneous fat depth

and KFI. Average fat depth for BCS 3 on the brisket was 6 mm, forequarter 1 mm,

loin 1.7 mm, rump 4.8 mm. Average KFI for BCS 3 was 62.8 (sem 1.4).

Chapter Four

124

Figure 4.3 : Live weights of the fallow bucks and haviers of BCS 2 and BCS 3 used in

this study.

There was no significant relationship between BCS and meat quality parameters of

bucks and haviers, therefore data were combined for BCS. A number of meat quality

attributes for bucks and haviers are shown in Table 4.3. The data shows that there

was no statistical difference between BCS 2 and 3 bucks and haviers for

intramuscular fat, meat colour lightness (L*), tenderness and moisture content.

However, the bucks had higher redness (a*) and lower yellowness (b*) values

compared with the meat from haviers (p<0.05).

Table 4.3 : Meat quality attributes of M.longissimus dorsi from fallow bucks and

haviers of BCS 2 and 3.

Sex HCW

(kg)

pH

Raw Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moist

(%)

IM Fat

(%)

Bucks 25.75a

(0.94)

5.45a

(0.08)

2404.2a

(217.67)

21.27a

(0.63)

12.05a

(0.40)

0.56a

(0.39)

74.99a

(0.17)

0.73a

(0.13)

Haviers 24.69a

(0.60)

5.42a

(0.06)

2073.9a

(283.0)

19.17a

(0.50)

10.60b

(0.41)

0.80b

(0.18)

75.04a

(0.16)

0.69a

(0.17)



(p<0.05).

0.0

10.0

20.0

30.0

40.0

50.0

60.0

1 2 3 4 5 6 7 8 9 10 11 12

L

i

v

e

w

e

i

g

h

t

k

g

Number of animals

BCS 2 Bucks

BCS 3 Bucks

BCS 2 Haviers

BCS 3 Haviers

Chapter Four

125

4.3.4: Red deer stags with BCS of 2, 3 and 4

The dressed weights of the BCS 2 stags ranged between 38.6 kg to 78.3 kg with an

average of 48.9 kg (sem 1.40) (Figure 4.4). Average fat depth at the GR site for BCS

2 was 2 mm (Figure 4.5).


average of 68.1 kg (sem 1.9) (Figure 4.4). Average fat depth at the GR site for BCS 3

was 3.5 mm (Figure 4.5).


average of 75.8 kg (sem 1.7) (Figure 4.4). Average fat depth at the GR site for BCS 4

was 5.8 mm (Figure 4.5).

Figure 4.4 : Hot carcass weights of the red stags used in this study.

0

10

20

30

40

50

60

70

80

BCS 2 BCS 3 BCS 4

Kg

Carcass Weight

Carcass Weight

Chapter Four

126

Figure 4.5 : Fat depth (GR) of the red stags used in this study.

In this experiment, there was a significant difference between BCS in shear force of

raw meat samples (F2, 23 = 4.341, p<0.05) with BCS 4 having lower shear force

values than BCS 2 or BCS 3. There was no difference between BSC 2 and BSC 3

shear force for cooked meat samples, however, BSC 4 was significantly lower for

cooked shear values (p<0.05). There were significant differences between BCS in

redness (F2, 23 =5.588, p<0.01), with BCS 3 and 4 having less redness, but not in

other measured colour parameters. There were also significant differences between

BCS in intramuscular fat (F2, 23 = 70.234, p<0.001) and in HCW (F2, 23 = 35.165,

p<0.001), with increasing values as BCS increased, but no significant differences

between BCS for other measured parameters (Table 4.4).

0

1

2

3

4

5

6

7

BCS 2 BCS 3 BCS 4

mm

GR depth

GR depth

Chapter Four

127

Table 4.4 : Meat quality attributes of M.longissimus dorsi from red stags of BCS 2 (n=1), 3 (n=6) and 4 (n=6).


Numbers in the columns with the same letter are not significantly different (p<0.05).

4.4: Discussion

In this series of experiments carcass quality characteristics for entire fallow bucks,

castrated fallow bucks and fallow does, as well as red deer stags, with a BCS

between 2 and 4 were established.

4.4.1: BCS and live weight

The range of live weights for fallow deer included in the study fell within the target

sale weight range of 25 kg to 35 kg (Tuckwell 2003b). The red deer in the study

included two animals that failed to fit within the premium carcass weight ranges of

55 kg to 75 kg for red deer (Tuckwell 2003b), with one animal having a HCW of

38.6 kg and therefore below the schedule, and another over the maximum at 78.3 kg,

while the remaining 24 animals were within the specified range.

Live animal BCS assessment was confirmed with post-mortem measurements of

subcutaneous fat depths and KFI. The majority of these data fell within the ranges

described by Flesch (2001). It is acknowledged that there may be variations between

animals and assessors which can affect estimations of the body condition of any

BCS pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moist

(%)

IM

Fat

(%)

Freeze

Thaw

loss

(%)

HCW

(kg)

BCS 2

(n= 14)

5.66 a

(0.03)

5724.3a

(397.7)

3810.6a

(243.2)

22.82 a

(0.48)

12.16 a

(0.34)

2.78 a

(0.25)

75.91 a

(0.15)

1.31 a

(0.17)

12.49 a

(0.80)

48.9 a

(2.4)

BCS 3

(n = 6 )

5.57 a

(0.03)

5403.5a

(292.8)

3330.4a

(184.5)

22.64 a

(0.34)

11.88 b

(0.34)

3.35 a

(0.11)

75.67 a

(0.26)

3.22 b

(0.34)

11.51 a

(0.97)

68.1 b

(2.9)

BCS 4

(n = 6)

5.63 a

(0.01)

4942.5b

(230.4)

2846.1b

(201.2)

23.62 a

(0.37)

11.80 b

(0.41)

3.58 a

(0.21)

76.13 a

(0.34)

4.84 c

(0.33)

12.34 a

(0.58)

75.8 b

(1.7)

Chapter Four

128

particular animal. There were a small number of discrepancies with fat deposition on

the does that formed part of this study. It has been noted by Flesch (2001) that fat

deposition in does may not always follow a consistent pattern, and this was evident

in this study, with fat deposition lacking consistency between measurement sites. In a

study by Mushi et al (2008) comparing lambs and goats, the EUROP system of BCS

was found to be an accurate discriminator of potential carcass composition, as did

Johansen et al (2008). The EUROP system, like the BCS system for red and fallow

deer, is a five grade system designed to assess fatness and body condition in the live

animal.

As body condition score increased, HCW and live weight increased, in both fallow

and red deer, particularly when comparing BCS 4 animals to BCS 2 and 3. This has

been confirmed in sheep, where heavier and higher condition animals were

significantly heavier than lower and medium condition animals (Okeudo and Moss

2005; Glimp et al 1998; Juarez et al 2009) and red deer where GR fat depth was

strongly correlated to carcass weight (Stevenson-Barry et al 1999).

4.4.2: Intramuscular fat

IMF increased as body condition score increased in all study animals, significantly

for the fallow deer does and red stags. Similar results have been found in sheep,

where animals of higher body condition were significantly higher in IMF than lower

and medium condition animals (Diaz et al 2004; Okeudo and Moss 2005; Glimp et al

1998; Juarez et al 2009), and in cattle (Weglarz 2010), where IMF increased with

carcass fatness score, particularly in heifers when compared with bulls. Similar

results were documented in higher body condition horses (Sarries and Berlain 2005).

There was no significant difference in IMF content between fallow deer bucks and

haviers. Carcass weights were not significantly different between fallow deer bucks

and haviers, as was the case with red deer (Kay et al 1981). Previous studies by

Mulley (1996) indicated that haviers have a higher percentage of body fat in terms of

carcass composition and better year round meat quality regardless of breeding

season. This was confirmed by Woodford et al (1996) with castrated blackbuck

Chapter Four

129

antelope. Although expected, this was not confirmed in the current study, possibly

because drought conditions prevailed at the time of raising and slaughter. Lack of

feed availability reduced the ability of animals to store fat in typical carcass fat

deposition areas. The experiment was not repeated in times of better quality and

availability of pasture, since by the time the drought had abated, venison producers

had ceased the practise of castrating fallow deer bucks and the experimental finding

was no longer of commercial importance. A recent study by Asher et al (2011) on

red deer and wapiti-red hybrid stags noted that there was a delay of between 6 and 23

days in reaching slaughter weight in castrated animals. Carcass composition was

measured on the live animal by CT scanning and results confirmed with carcass

measurements post-slaughter. The carcass traits demonstrated a linear relationship

with body weight. The study concluded that there were no significant effects of

castration on any musculature, and only a minor effect of increased fatness within the

hind leg. Their findings support the results of this study, where there was no

significant difference between bucks and haviers, apart from meat colour, which was

not determined in the study by Asher et al (2011). Hogg et al (1990) similarly found

little effect of castration, with minor differences in musculature and fat deposition,

but commented on issues of reduced production due to lower live weight gains and

meat yields. A study of blackbuck antelope also determined that castration caused a

reduction in live weight gain but had no significant effect on slaughter or carcass

weight when compared with entire animals (Woodford et al 1996). Much of the

effect of steroid hormones on the growth of entire animals results in increased

weight of hide and bone (Mulley 1989), and this appears to be why reduced live

weight gain of castrates is not translated into carcass weight differences between

entire and castrates males in this and previous studies. Once entire males are dressed,

the heavier head, hide and bones of the extremities are lost as offal and the carcass

weight is then similar to that of castrated males of the same age.

4.4.3: Shear force

In the current study meat tenderness of venison increased as BCS increased,

significantly so when BCS 4 fallow does and red deer stags were included in the

study. This is in agreement with findings in steer carcasses where fatter carcasses

Chapter Four

130

displayed better tenderness than leaner carcasses (Pflanzer and Felicio 2009). In this

study, there was no significant difference in tenderness when comparing venison

from BCS 2 animals with BCS 3. BCS 4 animals, however, were significantly more

tender than the other two scores. Although venison from BCS 4 animals was more

tender, BCS 2 and 3 animals provided venison of acceptable tenderness, with shear

force values predominantly below 5.0 kg, and all well below 6.0 kg. A Warner-

Bratzler shear force value of over 5 kg is a nominal and arbitrary estimate of the

threshold for consumer acceptability of tenderness in lamb and sheep meat (Russell

et al 2005). This finding is of importance to venison producers when determining the

condition of animals for slaughter and for producing venison for particular markets.

In a study by Wiklund et al (2010) on seasonal variation in red deer venison, the deer

slaughtered prior to the rut had higher carcass weights and GR fat depths, and the

most tender meat compared with animals slaughtered at other times of the year. In

this study higher BCS animals had the most tender meat also, and the highest carcass

weights in both red deer and fallow deer venison. Conversely, tenderness is known to

decrease as slaughter weight increases in lamb (Martinez-Cerezo et al 2002;

Abdullah and Qudsieh 2009; Tejeda et al 2008) and beef (Sanudo et al 2004; Maher

et al 2004), where animal condition is not used as a slaughter parameter.

In a New Zealand study, venison from red deer hinds was more tender than venison

from stags (Purchas et al 2010), as was the case in this study for fallow deer does and

bucks. In this study does were also more tender at all body condition scores despite

being 12-18 months older than the males. Within sexes it has been shown that

tenderness decreased with advancing age in fallow deer bucks (Volpelli et al 2005;

Pinto et al 2009); red deer stags (Stevenson et al 1989a); blackbuck antelope

(Woodford et al 1996); camels (Dawood 1995); goats (Rodrigues et al 2011); and

lamb (Hopkins et al 2006, 2007; Pethick et al 2002, 2005b; Thompson et al 2005b).

However, between sexes this study showed that older females were more tender than

younger males both in instrumental measures and sensory evaluation (Hutchison et al

2010). A study on venison from red deer hinds (Stevenson et al 1989a) found that

unless the carcasses were visibly emaciated, the venison was of uniformly high

quality and tenderness irrespective of animal age, which ranged from 1 year to 13

years of age. Female roe deer have also been reported (Daszkiewicz et al 2012) to

exhibit lower shear force values compared to males. This has been confirmed in beef

Chapter Four

131

cattle, with heifers providing more tender meat than bulls or steers at the same age

(Lundesjo et al 2003, Daszkiewicz et al 2005; Weglarz 2010) and cows more tender

than bulls (Jelenikova et al 2008). Similar results are reported in lamb, with ewe

lambs providing more tender meat with higher levels of IMF than ram lambs (Craigie

et al 2012). Therefore, one can speculate from these studies that this is a difference

related to sex rather than age, with female animals having slightly higher IMF and

smaller diameter of muscle fibres than males of the same species. In a study on bulls,

muscle fibre area highly correlated with age and classification of EUROP score,

resulting in poorer eating quality of the meat (Mlynek et al 2007).

Purchas et al (2010) noted that red deer hinds had greater GR depths (NS) than stags,

and the hinds had significantly higher levels of IMF. Higher IMF levels were also

confirmed for hinds when compared to red stags in a study by Polak et al (2008) and

roe deer does when compared to bucks (Daszkiewicz et al 2012). In the study by

Purchas et al (2010) tenderness was improved due to greater IMF and slightly longer

sarcomeres. Red deer stags also had higher cooking losses and lower water holding

capacity (Purchas et al 2010). This was confirmed in a study of wild red deer

(Daszkiewicz et al 2009), where red deer stags had higher shear force values than

hinds. This study reported low collagen levels in stags that were further reduced in

the hind population measured (Daszkiewicz et al 2009). Although higher collagen

concentrations in muscles from red stags and fallow bucks, compared to fallow deer

does, haviers and red deer hinds, have not been reported as they have for lamb; these

findings may provide an explanation for differences in tenderness between sexes of

fallow and red deer venison (Dransfield et al 1990).

Tender venison without ageing, as was the finding in this experiment, has been

reported by other authors (Wiklund et al 2003b; Kochanowska-Maturszewska 2004).

Various other game animals have been examined for meat quality: springbok and

impala (Hoffman 2000); blackbuck antelope (Woodford et al 1996); wildebeest (van

Schalkwyk 2004); reedbuck (Hoffman et al 2008b); and kudu (Hoffman et 2009),

and have been found to produce universally tender meat when compared with

domestic meat species such as goats, beef cattle and sheep.

Chapter Four

132

4.4.4: Freeze-thaw/purge

Freeze-thaw purge losses were significantly higher in fallow deer bucks of BCS 3

when compared with BCS 2. Bucks of BCS 3 had a tendency to exhibit higher

moisture content, though this was not significant. Significantly higher losses may be

a result of a number of factors relating to water holding capacity, moisture content,

muscle structure, freezing quality and fat percentages. One outcome from freezing

meat is the amount of exudates that arise during thawing, as freezing causes an extra

loss of water compared with fresh chilled meat (Anon and Calvelo 1980; Leygonie et

al 2012). When meat is frozen, water is removed from within the muscle cells which

provides a potential reservoir of fluid that appears as drip on thawing (Lawrie and

Ledward 2006). Moore and Young (1991) determined that the dominant cause of

drip loss was the type of the freeze-thaw system and resultant cellular damage (Anon

and Calvelo 1980; Leygonie et al 2012). Given that all samples were frozen in the

same manner in the present study, this is an unlikely explanation for these results.

Daszkiewicz et al (2009) found that water holding capacity and association of free

water with protein was pH dependent. Post-mortem rate and extent of pH decline,

proteolysis and protein exudation are believed to be key influences in the ability of

meat to hold moisture (Huff-Lonergan and Lonergan 2005). While the mean pHu of

the BCS 3 bucks was slightly higher than the bucks of BCS 2, this was not

significant. Hoffman et al (2009) related drip loss to water holding capacity (WHC)

of meat which is influenced by several factors including the extent of post-mortem

pH fall. It is believed that higher muscle pH causes less water release from the

muscle since WHC is at a minimum between pH 5.0 and 5.5, which corresponds to

the isoelectric point of the protein within the muscle (Bouton et al 1971; Offer and

Knight 1988). This is confirmed by Hoffman et al (2007) who reported that very low

pHu values resulted in higher drip losses from the LD samples of springbok. Oddy et

al (2001) speculated that carcass size and fatness can interact with drip loss due to

the effect on chilling rate and glycolysis. Fast rates of pH decline and low pHu are

related to high purge losses as proteins lose the ability to bind water during rapid

proteolysis (Huff-Lonergan and Lonergan 2005). The pHu of carcasses from bucks of

both BCS 2 and 3 was not considered to be low, and venison is considered to be

more likely to have higher pHu and produce dry, firm and dark (DFD) meat rather

Chapter Four

133

than pale, soft and exudative (PSE) meat (Stevenson-Barry et al 1999). Low pHu

values and associated drip loss is a phenomenon that has been studied extensively on

pork where certain genetic traits in pigs can result in meat that is pale, soft and

exudative. This genotype results in abnormal flow of calcium across the

sarcoplasmic membrane of muscle cells, and fluid accumulates outside the myofibre

bundles and drips from the muscle, resulting in dry eating quality of the meat (Oddy

et al 2001). In this study the mean pH of BCS 3 bucks was within the optimal range

(5.4-5.7), therefore variation in pH cannot explain the result in this case. Does in this

study had higher mean freeze-thaw losses across all BCS than the BCS 3 fallow deer

bucks, while red stags had similar mean freeze-thaw losses. This was also reported

in roe deer does (Daszkiewicz et al 2012) where drip loss was higher when compared

to bucks. Wiklund et al (2010) speculated that seasonal variation in protein accretion

and catabolism, which relates to proteolysis and meat tenderness, would likely also

impact on WHC. Whether this has an effect on animals of higher BCS is unknown. A

similar finding in red deer venison (Wiklund et al 2010) demonstrated that animals

with higher BCS and higher carcass weights had the highest drip loss values, and

they speculated that high tenderness of the meat and loss of meat texture with

subsequent purge of moisture is a possible cause. This may also explain the higher

losses in venison from fallow deer does and bucks of BCS 3 in the current study,

however, this finding was not confirmed in any of the other venison analysed in the

study and would warrant further experimental investigation to confirm validity of the

result.

4.4.5: Colour

Colour measurements on the venison in this study revealed a decrease of redness (a*

value) as BCS increased. The lower redness values were only significant for BCS 4

red deer stags and BCS 4 fallow deer does compared with other BCS categories. This

decrease in redness may be related to fat deposition within the muscle. Hocqette et al

(2006) speculated that differences in levels of IMF and proportion of different

muscle fibre types may lead to differences in meat colour and tenderness. Meat from

goats (Madruga et al 2008) and lambs (Perlo et al 2008; Diaz et al 2002) with low

BCS had higher redness values. A study comparing meat from goats and lambs

Chapter Four

134

found that goats had higher redness values than lambs, and it was believed to be

associated with increased fatness in the lambs (Mushi et al 2008) and lower carcass

fatness in goats (Mushi et al 2008; Priolo et al 2002). Moloney et al (2008) also

found decreasing redness values over a longer concentrate feeding time in beef

correlated with increasing carcass weights. Stevenson-Barry et al (1999) determined

that increasing redness values correlated with an increase in animal age or pH, and

increased toughness in red deer venison and in beef (Triumf et al 2012). This

supports the findings for venison in this study where the lowest redness values were

measured in the most tender venison and therefore, lack of redness may be a possible

indicator of tenderness in venison. A pasture feeding study by Purchas and Zou

(2008) found that Wagyu-cross steers had lighter meat and the lowest shear force

values, while Friesen bull beef was darkest and least tender. The authors speculated

that the colour measures were due to high levels of fat marbling in the longissimus

muscle of the Wagyu-cross steers. In agreement with this study, there was no

significance difference in pHu between groups. Meat from lambs with lower GR

depths has also been shown to be leaner and more red (Perlo et al 2008; Diaz et al,

2002). Fallow deer haviers of BCS 2 and 3 had lower redness and yellowness than

fallow deer bucks of the same BCS, which may be attributable to hormonal status,

muscle activity and fat accretion. Animals in this study were slaughtered in April,

shortly after the completion of the rut, which may explain differences in meat colour,

because haviers are unaffected by breeding season. Stevenson et al (1992) reported

that leaner post-rut venison from red deer stags was redder than pre-rut meat which

also exhibited higher GR fat thickness. Redness of meat depends on the content and

state of heme pigments in the muscle. Meat with higher redness values, as with BCS

2 animals in this study, exhibits increased levels of oxymyoglobin and lower levels

of metmyoglobin (Fernandez-Lopez et al 2000). Animals that have higher levels of

myoglobin are likely to be more physically active and possibly more aggressive than

animals with lower levels (Mushi et al 2008). Animals grazing on pasture tend to be

more physically active and often leaner than those on feedlots, and have subsequent

higher amounts of heme pigments in the muscle.

Chapter Four

135

4.5: Conclusions

This study confirmed the inconsistent relationship between live weight and BCS. The

variation in BCS resulted in some differences in the measured meat quality

parameters for fallow and red deer. The fallow does with BCS 4 had higher IMF

content than BCS 3 and BCS 2. This difference in IMF content was also the most

obvious quality variation between BCS 3 and 4 for red deer. Sensory analysis and

consumer acceptance data were collected to test the hypothesis that BCS and venison

quality attributes are related to consumer expectation for the primary measures of

eating quality such as tenderness, juiciness and flavour (Chapter 7). A relationship

between BCS and consumer acceptance has previously been established for sheep

(Glimp et al 1998) and beef cattle (Gresham et al 1986; Hoving-Bolink et al 1999),

with USDA and Meat Standards Australia (MSA) grading systems well established

on domestic and international markets. This has re-established consumer confidence

and premium prices for product of consistent description and quality in those

industries. It remains to be seen if the BCS descriptor system established for deer and

the relationships now established with meat quality can be used by industry in a

similar way to bring about product consistency for venison.

In the present study red and fallow deer between 12 and 30 months of age raised on

pasture usually had a BCS between 2 and 3. In Australia, most deer are raised on

pasture and slaughtered for venison within this age range, and are unlikely to achieve

BCS 4 unless supplementary-fed in these age groupings (Chapter 5).

Venison quality within these age groupings and body condition scores is of

consistently high quality in terms of the major meat quality parameters of pH, colour,

tenderness and intramuscular fat. Venison that has increased tenderness and IMF

may be achieved by obtaining BCS 4 animals or processing does.

Venison producers are currently paid per kg of hot carcass weight. The target

premium carcass weight ranges specified by Tuckwell (2003) are 25 kg to 35 kg for

fallow deer, and 55 kg to 75 kg in red deer, regardless of sex, animal age and BCS.

By utilising the BCS system along with live weight, producers of venison can deliver

Chapter Four

136

an animal with the view to supplying optimal quality venison for specified markets

and then be paid accordingly. This system should aid producers and processors alike

in achieving better quality assurance for Australian venison.

Chapter Five

137

Chapter Five

Effect of concentrate feeding on meat quality

parameters of venison from fallow deer does

Fallow deer doe at the UWS Deer Research Unit

Chapter 5 Effect of concentrate feeding on meat quality parameters of venison from fallow deer does ............................................................................................. 137

5.1: Introduction .................................................................................................. 138

5.2: Materials and methods ................................................................................. 140

5.3: Results ........................................................................................................... 142

5.4: Discussion ..................................................................................................... 151 5.4.1: BCS ........................................................................................................ 151 5.4.2: pHu ......................................................................................................... 151 5.4.3: Freeze-thaw purge .................................................................................. 152 5.4.4: Intramuscular fat and tenderness............................................................ 152 5.4.5: Colour .................................................................................................... 153

5.5: Conclusions ................................................................................................... 156

Chapter Five

138

5.1: Introduction

Body condition score is a useful tool in assessment of animal well-being (Flesch et al

2002), and a frequently used descriptor in the buying and selling of livestock for

slaughter. The BCS of an animal can be altered by the presence or absence of

supplementary feeds. Meat production systems for beef (Hunter et al 2001), lamb

(Pethick et al 2005a) and goat meat (Adam et al 2010; Madruga et al 2008)

frequently utilise supplementary feeding to increase feed conversion efficiency and

to produce carcasses that consistently meet market specifications. Market

specifications are often established according to the amount of subcutaneous fat

coverage on the live animal (Gaden et al 2005) and scales of reference have been

established that allow accurate prediction of carcass characteristics from live animal

BCS assessments in fallow (Flesch et al 2002) and red deer (Audige et al 1998;

Tuckwell 2003b).

Supplementary feeding strategies are often implemented in the production of red

meat in order to finish animals and achieve desired live weight targets prior to

slaughter (Cozzi et al 2009; Dannenberger et al 2006). Concentrate feeding is also

used to manipulate meat quality parameters such as degree of fatness and marbling

(Kerth et al 2007; Moloney et al 2008), fatty acid composition and flavour profiles

(Font i Furnols et al 2007). Studies on the effect of supplementary feeding with

concentrate feeds in relation to these meat quality parameters have been carried out

for beef (Cozzi et al 2009); lamb (Font i Furnols et al 2009), reindeer (Wiklund et al

2003a); and red deer (Phillip et al 2007).

Fallow deer are frequently fed concentrates over winter (Flesch et al 2002) or in

times of pastoral feed deficiency (Tuckwell 2003b). In the quest to meet market

specifications for fallow deer, it is necessary to also understand the effects of

supplementary feeding prior to slaughter on eating quality. Cooking methods are

usually implicated in changes to odour and flavour of meat. The type of feed

consumed immediately prior to slaughter by other domesticated animals used for

meat production, such as cattle (Resconi et al 2010) and sheep (Resconi et al 2009),

has been shown to alter the flavour of meat, with Lawrie and Ledward (2006)

Chapter Five

139

indicating that the degree of fatness of the carcass can also change perceptions of

flavour.

Studies comparing the effects of grain vs. pasture finishing have usually been

conducted in the major meat species, cattle and sheep. McCaughey & Cliplef (1996)

fed steers with grain over 33 or 75 days prior to slaughter and compared the meat

quality with meat from animals in a pasture control group. The study demonstrated

that while pasture finished steers had lower yields and darker meat, there were no

effects on tenderness, juiciness, flavour and overall acceptability according to

consumer testing, with the majority of animals meeting market requirements. Similar

studies were conducted by Pethick et al (2005a) on lamb resulting in

recommendations that the decision to grain finish should be based on production

costs due to the limited impact on eating quality.

Dahlan et al (2008) conducted a study looking at the chemical composition of farmed

tropical and temperate deer species. Fallow, sambar and Javan rusa deer were fed

concentrates which resulted in higher IMF content than the grazing Moluccan rusa

and red deer. As a species, fallow and red deer exhibited higher IMF than rusa and

sambar deer regardless of feed type. Venison from supplementary-fed deer was

redder in colour than grass-fed deer. Higher palatability feeding regimes significantly

influenced fat composition. Feeding red deer and reindeer commercial feed mixtures

(grain-based pellets) for 8-10 weeks prior to slaughter has been demonstrated to

significantly change the quality of venison compared with control groups of animals

grazing natural pasture before slaughter (Wiklund et al 2001a; 2003a; 2003b).

For the deer industry it is important to acknowledge the impact of feed type (pasture

vs. grain) on the quality of the meat. The image of venison is largely focused around

natural grazing to produce lean, nutritious meat (Tesanovic et al 2011). This study

investigated the influence of supplementary feeding, prior to slaughter, on carcass

and meat quality attributes of venison from fallow deer does.

Chapter Five

140


Twenty four non-pregnant fallow deer does (at the commencement of the trial were

approximately 36 months old, with an average live weight of 43 kg and BCS 2)

(Flesch et al 2002) raised at UWS were included in the study. The animals were

quarter-bred hybrids of European type fallow deer (Dama dama) and the

Mesopotamian type (Dama dama mesopotamica), with European fallow deer being

the dominant influence. All does, prior to the feeding trial, had been raised on kikuyu

pasture, oversown with ryegrass and oats during winter. Twelve animals were grazed

on kikuyu pasture oversown with ryegrass and oats in winter. The remaining twelve

animals were fed lucerne hay (500 g/animal/day) and steam rolled barley (800

g/animal/day) during the feeding period.

Body condition score was assessed for each animal at the commencement and

completion of the trial using live palpation techniques as described by Flesch et al

(2002) (Plate 5.1). Animals were slaughtered using the methods described in Chapter

3. Animals were slaughtered in two groups: group 1 after 135 days (n=12; 6 grazing

and 6 barley/hay fed animals) and group 2 after 170 days (n=12; 6 grazing and 6

barley/hay fed animals) of feeding treatment. Dressed carcass weights, muscle pH

and core body temperatures were recorded 1-2 hours post-slaughter, and kidneys

excised. Carcasses were then transferred to the chiller. Core body temperature and

pH were logged hourly for 12 hours after slaughter. At 24 hours post-mortem,

ultimate pH (pHu) measurements and final core body temperatures were recorded.

Carcasses were examined to confirm BCS via fat depths and KFI. Samples of LD

(from the right side), as described in Chapter 3, were then excised and stored at

-21 ˚C for no more than 12 weeks for later analysis. Samples were analysed for

colour, drip loss and tenderness, as described in Chapter 3.

Chapter Five

141

Plate 5.1 : Fallow doe in the handling cradle for palpation to assess BCS over the rump.

At 24 hours post-mortem, LD from the left side of each carcass was excised, cut into

four equally sized pieces that were randomly allocated to sampling at 24 hours post-

mortem, or 1, 2 or 3 weeks of refrigerated storage at ±2 ºC. Samples allocated for

storage were vacuum packaged. Each muscle was sampled at 24 hours post-mortem

for colour measurements. Drip loss (purge in the vacuum bags) and meat colour was

measured after 1, 2 and 3 weeks of refrigerated storage at ±2 ºC, as described in

Chapter 3.

Triplicate colour measurements were made on each freshly cut steak 2 hours after

opening the vacuum bag, then twice daily as found appropriate for venison

(Stevenson et al 1989b). Days of acceptable colour (display life) were calculated as

the time taken to reach a redness (a*) value of 12 using linear interpolation between

consecutive samples, as previously determined for red deer venison (Stevenson et al

1989b; Wiklund et al 2001c).

Carcass measurements, pH, temperature decline, colour stability and drip loss data

were analysed using analysis of variance, fitting treatment, time on feed and their

interaction. All analyses were conducted using GenStat (2002).

Chapter Five

142

5.3: Results

The live weight of the pasture-fed group after 135 days ranged between 38 kg and

44.5 kg giving an average weight of 42.3 kg. Body condition scores confirmed via

measurement of subcutaneous fat depth and KFI were predominantly BCS 2, with

only two animals achieving BCS 3 in the 135 day feeding period. Dressed weights

ranged from 26.5 kg to 29 kg with an average of 28.4 kg indicating an average

dressing percentage of 67%. Average fat depth for BCS 2 on the brisket was 2.8

mm, forequarter 0 mm, loin 0.4 mm and rump 3.4 mm. The average fat depths for the

BCS 3 does on the brisket were 8 mm, forequarter 2 mm, loin 2 mm and rump 9 mm.

Average KFI for BCS 2 was 49.6, and 97.1 for the BCS 3 animals.

The live weights of the concentrate-fed group after 135 days ranged between 41.5 kg

and 50 kg giving an average weight of 44.9 kg. Body condition scores were

confirmed via measurement of subcutaneous fat depth and KFI, with 2 animals

attaining BCS 3, and the majority of animals achieving BCS 4 in the 135 day feeding

period. Dressed weights ranged from 28.5 kg to 33 kg with an average of 30.1 kg

indicating an average dressing percentage of 67% (Figure 5.1). Average fat depth for

BCS 3 on the brisket was 6 mm, forequarter 2.5 mm, loin 2.5 mm and rump 7 mm.

The average fat depths for BCS 4 on the brisket were 8.5 mm, forequarter 4.1 mm,

loin 3.5 mm and rump 9 mm. Average KFI for BCS 3 was 100.5, and 137.4 for BCS

4.

Figure 5.1 : Comparison of weights and dressing percentages for fallow does fed

pasture or concentrates for 135 days prior to slaughter.

Chapter Five

143

The live weights of the pasture-fed group after 170 days ranged between 39 kg and

43 kg with an average weight of 41.8 kg. Body condition scores confirmed via


only two animals achieving BCS 4 and one animal remaining at BCS 2 in the 170

day feeding period. Dressed weights ranged from 22.9 kg to 25.9 kg with an average

of 25.3 kg, indicating an average dressing percentage of 61%. Average fat depth for

BCS 3 on the brisket was 4.3 mm, forequarter 1.5 mm, loin 2.5 mm and rump 4.5

mm. The fat depth for the BCS 2 doe on the brisket was 1 mm, forequarter 0 mm,

loin 0.5 mm and rump 2 mm. The average fat depth for the BCS 4 does on the brisket

was 5 mm, forequarter 2 mm, loin 3.5 mm and rump 7 mm. Average KFI for BCS 3

was 116.4, 97.2 for the BCS 2 animal and 140 for BCS 4 animals.

The live weight of the concentrate-fed group after 170 days ranged between 37 kg

and 46 kg with an average weight of 42.7 kg. Body condition scores confirmed via


only two animals remaining at BCS 3 in the 170 day feeding period. Dressed weights

ranged from 23.8 kg to 29.6 kg with an average of 27.5 kg indicating an average

dressing percentage of 64% (Figure 5.2). Average fat depth for BCS 4 on the brisket

was 5.1 mm, forequarter 2.5 mm, loin 2.9 mm, rump 8.6 mm. The average fat depth

for the BCS 3 does on the brisket was 3 mm, forequarter 1 mm, loin 1.9 mm and

rump 5.5 mm. Average KFI for BCS 4 was 136.3, and 107.1 for the BCS 3 animals.

Figure 5.2 : Comparison of weights and dressing percentages for fallow does fed

pasture or concentrates for 170 days prior to slaughter.

Chapter Five

144

The fallow deer fed concentrates had significantly higher body condition scores

(p<0.001) and carcass weights (p<0.01) than pasture-fed animals. Carcass weights

were significantly different, relative to time on feed (p<0.001), with carcass weights

being higher over 135 days compared with 170 days. Dressing percentages were

significantly higher in the 135 day group (p<0.001), related to time on feed

(p<0.001) and feed type, with concentrate-fed animals having higher percentages

than pasture-fed in the 170 day treatment group (p<0.05) (Table 5.1).

Table 5.1 : BCS, weights and dressing percentages from fallow does measured at either

135 or 170 days after commencement of feeding with concentrates (n=6 per group),

compared with pasture-fed controls.

Parameters 135 days Concentrate feeding 170 days Concentrate feeding

Pasture Concentrate Pasture Concentrate

BCS 2.42a

(0.27)

4.25b

(0.26)

2.67a

(0.29)

3.50a

(0.27)

Live weight (kg) 42.3a

(1.59)

44.9a

(1.23)

41.8a

(1.49)

42.7a

(1.27)

Carcass weight (kg) 28.4a

(0.92)

30.1b

(0.94)

25.3a

(0.98)

27.5a

(0.94)

Dressing percentage (%) 67.2 a

(1.17)

67.1a

(1.15)

60.5b

(1.18)

64.4c

(1.19)

Means and standard error of means (in parenthesis) are shown. Numbers within rows without

common superscript letters are different (p<0.05).

There was a signficant difference between pasture and concentrate-fed carcasses for

temperature and pH decline. Pasture-fed deer had carcasses with lower mean

temperatures in the LD than carcasses from the concentrate-fed group at 1, 2, 6, 7, 8,

9 and 12 hours post-mortem (p< 0.05) (Figures 5.3 and 5.4).

Chapter Five

145

Figure 5.3: Temperature decline for carcasses from the fallow does fed pasture or

concentrates for 135 days prior to slaughter.

Figure 5.4 : Temperature decline for carcasses from the fallow does fed pasture or

concentrates for 170 days prior to slaughter.

The pH values in the LD from the concentrate-fed group were lower at 1, 3, 4, 5, 6,

7, 8, and 12 hours post-mortem (p<0.05) than in those fed on pasture only. However,

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 12 24 1w 2w 3w

tem

p º

C

hours post mortem

Temperature decline LD 135 days

pasture

grain

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 12 24

tem

p º

C

hours post mortem

Temperature decline LD 170 days

pasture

grain

Chapter Five

146

at 24 hours post-mortem, there was no significant difference between the two

treatment groups.

Figure 5.5 : pH decline of M.Longissimus dorsi after 135 days of feeding.

Figure 5.6 : pH decline of M.Longissimus dorsi after 170 days of feeding.

The pHu values measured at 24 hours post-mortem were significantly higher in the

pasture-fed group slaughtered at 135 days than in the group slaughtered at 170 days

(p<0.01). However, there was no significant difference in pH values between

treatment groups at any of the storage times (Table 5.2).

5.00

5.20

5.40

5.60

5.80

6.00

6.20

6.40

6.60

1 2 3 4 5 6 7 8 9 10 12 24 1w 2w 3w

pH

time post mortem

pH decline LD 135 days

pasture

grain

5.20

5.40

5.60

5.80

6.00

6.20

6.40

6.60

1 2 3 4 5 6 7 8 9 10 12 24 1w 2w 3w

pH

time post mortem

pH decline LD 170 days

pasture

grain

Chapter Five

147

Table 5.2: pH over storage times from fallow doe venison measured at either 135 or 170

days after commencement of feeding with concentrates (n=6 per group), compared with

pasture-fed controls.



24 hours 5.50a

(0.02)

5.58a

(0.02)

5.63b

(0.03)

5.56a

(0.02)

1 week 5.50a

(0.02)

5.52a

(0.01)

5.52a

(0.02)

5.45a

(0.02)

2 weeks 5.51a

(0.03)

5.52a

(0.02)

5.49a

(0.02)

5.46a

(0.04)

3 weeks 5.53a

(0.03)

5.56a

(0.03)

5.54a

(0.02)

5.49a

(0.02)



There was no significant difference between feeding treatments in the amount of drip

loss (purge) at any storage time measured (Figures 5.7 and 5.8)

Figure 5.7 : Drip loss following storage of venison from fallow does after 135 days of

feeding.

0

0.5

1

1.5

2

2.5

3

3.5

4

1w 2w 3w

Dri

p lo

ss %

Storage time

Drip loss during chilled storage 135 days

pasture

grain

Chapter Five

148

Figure 5.8 : Drip loss following storage of venison from fallow does after 170 days of

feeding.

There was, however, a significantly lower drip loss recorded in meat from animals

slaughtered at 135 days compared with meat from those slaughtered at 170 days

(p<0.001 ) (Table 5.3).

Table 5.3 : Percentage drip loss (purge) over storage times for fallow doe venison

measured at either 135 or 170 days after commencement of feeding with concentrates

(n=6 per group), compared with pasture-fed controls.



1 week 1.95a

(0.26)

2.29a

(0.25)

0.98b

(0.26)

1.16b

(0.27)

2 weeks 2.92a

(0.37)

2.85a

(0.37)

1.40b

(0.36)

1.69b

(0.36)

3 weeks 3.30a

(0.42)

3.56a

(0.40)

2.06b

(0.43)

2.04b

(0.41)



0

0.5

1

1.5

2

2.5

1w 2w 3w

Dri

p lo

ss %

Storage time

Drip loss during chilled storage 170 days

pasture

grain

Chapter Five

149

Venison from animals raised on pasture had longer (p<0.01) display life after 2 and 3

weeks refrigerated storage than venison from the concentrate-fed group, regardless of

time on feed.

There were significant differences between BCS for tenderness (shear force values)

(F2,18=3.984, p<0.05) and intramuscular fat content (F2,18 = 7.988, p<0.01) in both

pasture and concentrate-fed groups, with meat from BCS 4 carcasses being more

tender and having higher content of IMF than meat from BCS 2 and BCS 3 carcasses

(Table 5.4).

Table 5.4 : Meat quality attributes of M.longissimus dorsi from fallow deer does with

BCS 2, 3 and 4 fed on pasture or concentrates.

Parameters Pasture feeding Concentrate feeding

BCS 2

n = 5

BCS 3

n = 5

BCS 4

n = 2

BCS 2

n = 2

BCS 3

n = 2

BCS 4

n = 8

pH 5.48a

(0.05)

5.49a

(0.10)

5.52a

(0.03)

5.48a

(0.05)

5.46 a

(0.01)

5.46 a

(0.10)

IM fat (%) 2.23a

(0.07)

2.51a

(0.73)

3.15b

(0.65)

1.36a

(0.68)

2.70 a

(0.70)

3.99 b

(1.76)

Colour L* 21.60 a

(1.12)

20.96a

(1.38)

21.69a

(0.76)

20.86a

(0.81)

19.71a

(0.27)

21.90a

(1.68)

Colour a* 11.77a

(1.20)

11.66a

(0.67)

10.97a

(0.22)

11.53a

(0.31)

11.67a

(0.20)

11.69a

(1.08)

Colour b* 3.16a

(0.70)

2.80a

(0.74)

2.96a

(0.23)

2.14a

(0.21)

2.24a

(0.28)

3.19a

(1.08)

Cook Shear force (kg) 4.48a

(0.45)

4.64a

(0.69)

4.21b

(0.24)

4.80a

(0.22)

4.44a

(0.12)

3.61b

(0.57)

Moisture (%) 75.78a

(1.09)

75.60a

(0.31)

75.61a

(0.21)

75.79a

(0.18)

74.53a

(0.11)

75.13a

(0.36)

Freeze-thaw purge (%) 20.44a

(2.24)

16.65a

(1.99)

19.60a

(1.12)

14.60a

(0.97)

22.89 a

(4.07)

18.77a

(2.22)



There were also differences in meat colour between animals fed for 135 days

compared with animals fed for 170 days, regardless of type of feed. Meat from

Chapter Five

150

animals fed for 170 days exhibited less redness (F1,18 = 5.903, p<0.01). Meat from

concentrate-fed animals was significantly more tender than pasture-fed (F1,18=5.524,

p<0.05) (Table 5.5).

Table 5.5 : Meat quality attributes of M.longissimus dorsi from fallow does measured at

either 135 or 170 days after commencement of feeding with concentrates (n=6 per

group), compared with pasture-fed controls.



pH 5.50 a

(0.04)

5.45a

(0.02)

5.48a

(0.09)

5.47a

(0.12)

IM fat (%) 2.36 a

(0.57)

3.49a

(1.23)

2.49a

(0.83)

3.61a

(2.27)

Colour L* 21.74a

(1.22)

21.45a

(2.15)

20.94a

(1.08)

21.45a

(1.24)

Colour a* 12.14a

(0.87)

12.17a

(0.70)

11.18b

(0.78)

11.18b

(0.89)

Colour b* 3.26a

(0.73)

3.06a

(1.21)

2.27a

(0.54)

2.82a

(0.91)

Cooked Shear Force (kg)

4.42a

(0.46)

3.76b

(0.56)

4.63a

(0.62)

3.94b

(0.78)

Moisture (%) 75.66a

(1.08)

74.93a

(0.36)

75.72a

(0.36)

75.24a

(0.50)

Freeze-Thaw purge(%) 19.69a

(3.16)

19.79a

(3.90)

17.89a

(2.06)

18.43a

(2.20)

HCW 28.42a

(0.97)

30.04a

(1.62)

25.25a

(1.36)

21.17a

(2.15)

Mean BCS 2.42a

(0.27)

4.25b

(0.28)

2.67a

(0.25)

3.50b

(0.31)



Chapter Five

151

5.4: Discussion

5.4.1: BCS

In this experiment it was clearly demonstrated that concentrate feeding of the fallow

deer does increased BCS (8 animals of 12 classified as BCS 4 compared with 2 of 12

for animals grazing pasture) (p<0.001). A study by Volpelli et al (2002) found

similar results in a study on fallow deer bucks fed a concentrate mixture for 16 weeks

prior to slaughter. The concentrate-fed deer had significantly higher live weights,

carcass weights, fat deposition and dressing percentages. This is also a consistent

finding in goats (Goetsch et al 2011) and feedlot beef cattle (Realini et al 2004;

Marino et al 2006; Minchin et al 2009). It could also be concluded in this study that

concentrate-fed fallow deer does had higher body condition scores and carcass

weights than the pasture-fed deer. Changes to body composition in deer fed

concentrates needs to be recognised in venison production systems.

5.4.2: pHu

Studies on reindeer have demonstrated that nutritional status and physical condition

obtained with the use of commercial feed mixtures has a considerable effect on

muscle glycogen and meat ultimate pH (pHu) values (Wiklund et al 2000). However,

the measured pHu values in the present study did not indicate a difference in muscle

energy content between the two treatment groups. Similar results were observed by

Volpelli et al (2003) where improved nutritional status did not alter muscle glycogen

stores in fallow deer bucks. There was, however, significantly higher pHu values in

the pasture-fed group slaughtered at 135 days compared with 170 days. The group

slaughtered at 170 days were held in lairage in summer, compared to spring for the

135 days group. The pasture group generally had lower BCS than the concentrate-fed

animals. It is possible that stress affected the pH scores for this group by depleting

glycogen stores prior to slaughter. It must also be noted that pH continued to decline

between 24 hours and 1 week post-mortem (Table 5.2). This suggests that the

ultimate pH had not been attained in the first 24 hours post-mortem. There was no

significant difference in pH from any group after one week of storage. Temperature

Chapter Five

152

decline was more rapid in the pasture-fed group. This is possibly due to the lack of

insulating fat coverage, allowing more rapid cooling.

5.4.3: Freeze-thaw purge

Type of feed did not impact on drip loss/purge results in the current study. However,

it was evident that the group slaughtered at 135 days had lower losses than those

slaughtered at 170 days. Similar studies have been conducted on the water holding

properties of beef (Varela et al 2004), lamb (Diaz et al 2002) and fallow buck

venison (Volpelli et al 2002). These studies confirm the findings from this study that

feed type does not alter water holding capacity of the meat. A study on red deer

found that levels of antioxidants in the meat, such as vitamin E, resulted in

differences in drip loss. One explanation for the difference between groups

slaughtered at 135 days compared with 170 days may be the changes in pasture

quality as the seasons moved from late winter through to summer. Animals

slaughtered at 170 days had access to pasture from the spring flush, which may have

affected antioxidant levels in the feed consumed. The differences may have been

large enough to account for the differences between the groups slaughtered at 135

days compared with those slaughtered at 170 days.

5.4.4: Intramuscular fat and tenderness

Animals with higher BCS in this study had significantly higher IMF content and the

meat was generally more tender. A number of studies in other meat species have

yielded similar results, with meat from red deer (Purchas et al 2010), foals (Franco et

al 2011), lambs (Bonacina et al 2011), goats (Goetsch et al 2011) and beef (Lee at al

2009; Turner et al 2011) exhibiting higher instrumental tenderness as IMF increased.

Muscle lipid content has been positively correlated to tenderness in meat (Turner et

al 2011) although the reasons for this remain unclear. Raw muscle shear values were

not affected but once cooked, the meat was less tender for the pasture-fed deer, as

was the case for beef (Thenard et al 2006). Meat from the concentrate-fed animals

was significantly more tender than meat from the pasture-fed animals. Similar

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153

findings have been demonstrated in beef (Dannenberger et al 2006; Lanari et al

2002) and lamb (Perlo et al 2008; Ekiz et al 2012).

5.4.5: Colour

The venison from animals fed either pasture or concentrates only for longer periods

prior to slaughter, in this study, exhibited less redness, although there was no

difference in colour as a result of feed type. Animals fed for 170 days had lower

redness values than those fed for 135 days. It is suggested that the increased BCS,

and associated increase in IMF content in the meat, may have decreased the redness

of the meat in animals fed for 170 days. Another explanation could be the low levels

of antioxidants in the concentrate feed, which was reflected in the meat colour.

Earlier studies in red deer (Wiklund et al 2006) have demonstrated that pasture has

higher levels of antioxidants compared with concentrate feed and that meat from

animals grazing pasture exhibit better colour stability compared with meat from

concentrate-fed animals (Wiklund et al 2006). Similar findings have been reported in

beef cattle (Lanari et al 2002; Dunne et al 2011) and lambs (Diaz et al 2002; Perlo et

al 2008). Conversely, the meat from goats (Madruga et al 2008; Rodrigues et al

2011) and lambs (Perlo et al; Diaz et al 2002; Ekiz et al 2012) with low BCS had

higher redness values. A beef cattle study on time on feed prior to slaughter (Sami et

al 2004) found no significant difference between grain and pasture feeding.

However, bulls fed for 138 days vs. 100 days prior to slaughter had increased BCS,

and a significantly lower redness value relating to heme pigment concentration, as

well as increased IMF (Sami et al 2004). Moloney et al (2008) also found decreasing

redness values over longer feeding time in beef correlated with increasing carcass

weights. Hessle et al (2007) also confirm that changes in carcass traits appear to be

related to length of finishing period, rather than levels of grain feeding. This is

similar to the finding in the current study.

In studies comparing grain and pasture feeding in cattle, Hoving-Bolink et al (1999)

found that beef heifers had increased levels of IMF, lighter coloured and more tender

meat when supplemented with grain. These data support findings in the deer in this

study, and also concur that diet had no effect on pHu values or thaw loss/purge. In

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154

beef, studies have shown that grain-supplemented cattle resulted in fatter carcasses

and produced the most tender beef (French et al 2001, Moloney et al 2011; Cozzi et

al 2009). A pasture feeding study by Purchas and Zou (2008) found that Wagyu-

cross steers had lighter meat and the lowest shear force values, while beef from

Friesen bulls of comparable size was darkest and least tender. The authors speculate

that the colour measures are due to high levels of fat marbling in the longissimus

muscle of the Wagyu-cross steers and in agreement with the present study, there was

no significant difference in pHu between groups. Dannenberger et al (2006) found

that IMF increased as a result of feeding concentrate. Carcasses from the pasture-fed

group had an IMF of 1.5% compared to the grain-fed group at 2.6%. There was no

significant difference in slaughter weights, however longer feed times were required

for pasture-fed animals to achieve slaughter weights. The beef from concentrate-fed

cattle was more tender and lighter in colour, and slaughter weights were achieved

earlier than in pasture-fed cattle. In this study on deer, higher BCS was achieved

faster in the concentrate-fed group, which increased IMF and tenderness and

produced meat with less redness. This result may support the proposition by Purchas

and Zou (2008) that the higher IMF content resulted in less red meat. Pellet-fed

lambs were found to provide the highest carcass yields and dorsal and kidney fat

thickness with lighter colour, high fat marbling and greater tenderness. Pasture-fed

lambs were leaner and more red (Perlo et al 2008; Diaz et al, 2002) with concentrate-

fed lamb being fatter and less red (Priolo et al 2002).

Meat discolouration (from red to brown) results from oxidation of deoxymyoglobin

and oxymyoglobin to metamyoglobin. Type of feed has been implicated in the rate at

which chilled meat display life declines in beef (Yang et al 2002), lamb

(Ponnampalam et al 2001), reindeer (Wiklund and Johansson 2011) and red deer

(Wiklund et al 2002). The present study found that pasture-fed meat held its redness

for a longer period than concentrate-fed meat. This is in agreement with studies on

red deer, where a positive effect of the components of a pasture diet on meat colour

display life was reported (Wiklund et al 2002). Venison from the fallow deer does

finished on pasture maintained the desired red meat colour for longer compared with

venison from the grain-fed deer, which is another good reason for pasture based

management systems from the perspective of consumer preference. The same

findings have been demonstrated in beef (Sapp et al 1999).

Chapter Five

155

There were no significant differences in other meat quality parameters between

animals fed pasture or grain in the current study. This confirms previous reports in

fallow deer bucks (Volpelli et al 2003), beef cattle (Muir et al 1998; Minchin et al,

2009; Pordomingo et al 2012), lambs (Pethick et al 2002; Ripoll et al 2012) and

goats (Adam at el 2010), where decisions to finish on grain or pasture can simply be

based on costs of production (Pethick et al 2005a) and time available to get animals

up to slaughter weights (Muir et al 1998).

In Australia, most deer are raised on pasture and slaughtered for venison within the

age range of 12 to 24 months, therefore the fatty acid composition of the venison

produced from red and fallow deer can be expected to be rich in polyunsaturated

fatty acids (PUFA), as described by Wiklund et al (2001a; 2003a). Concentrate

feeding and resultant higher BCS had a strong tendency to increase IMF content and

tenderness in the meat. Good pasture and feeding with grain-based pellets improved

the nutritional status and physical condition of reindeer (Wiklund et al 1996b) and

red deer (Wiklund et al 2003a), as well as fallow deer in the current study, and had a

considerable effect on muscle glycogen content and meat pHu values. The chemical

composition of the meat changed (Wiklund et al 2001a; 2003a;2003b) so that meat

from grazing animals contained more polyunsaturated fatty acids, while meat from

animals fed grain-based feeds had more saturated fat.

Venison generally has a low fat content but the fatty acid composition is still

important for meat shelf life and for the quality of processed meat products. PUFA

are more prone to oxidation compared with saturated fats, therefore the difference in

fat composition between grazing animals and animals fed grain-based feeds might

also affect the quality of processed meat products (Sampels et al 2004).

Phillip et al (2007) conducted a study on 180 red deer yearlings to determine the

effect of different feed types on deer raised for venison. Live weight gain was

linearly and positively correlated to the proportion of grain in the diet. Fatness was

also linear, aligned with increasing concentrate, even at fixed body weights for

slaughter. The fatty acid composition of the meat was also altered by the different

levels of concentrate feeding in that study. They concluded that high level grain

feeding is an effective nutritional strategy to enhance growth performance, with a

Chapter Five

156

negative impact on carcass fatness, offset by desirable changes in monounsaturated

fatty acids and conjugated linoleic acid. This confirms findings in the current study,

where fatness increased with concentrate feeding of deer as well as finishing time. It

was evident from this study that various meat quality parameters were affected by

type of feed and time on feed, however, none of these had a negative impact on

eating quality.

In other studies on deer, access to high quality pasture and feeding with grain-based

pellets improved the nutritional status and physical condition of both reindeer and

red deer, and had a considerable effect on muscle glycogen content and meat pHu

values (Wiklund et al 1996; Wiklund et al 2003a, Wiklund et al 2003b). Ultimate pH

is a well recognised factor influencing meat quality parameters such as tenderness

and colour of the meat (Wiklund et al 1996). In the present study there was no

difference in pHu between animals fed pasture or grain, or between animals of

different body condition score.

5.5: Conclusions

Type of feed has an impact on the nutritional status of fallow deer does. BCS may be

manipulated by supplementing pasture-fed animals with concentrate feeds. Feeding

concentrates was shown to increase BCS, carcass weight and dressing percentages.

These weights and dressing percentages were higher at 135 days over 170 days and

meat from the 135 day group exhibited lower drip loss. This indicates that there is

li ttle advantage to keeping animals on expensive concentrate feeds for extended

periods of time. A decision on whether or not to feed concentrates prior to slaughter

is contingent on financial factors and timing of slaughter. Meat from animals

produced by either pasture or feeding concentrates is satisfactory from a meat quality

perspective regardless of feed type. Pasture feeding resulted in meat with longer

chilled display life which is a positive for pasture based management.

For the deer industry, it is important to acknowledge the impact of feed type (pasture

vs. grain) on the chemical composition and quality parameters of the meat as well as

ethical aspects of the production systems. The image of venison is very much

Chapter Five

157

focused around natural grazing and ethical production techniques to produce a

healthy type of meat, which are attributes that consumers are increasingly looking for

when purchasing meat and other food products.

Chapter Six

158

Chapter Six

Relationship between post-slaughter

management and meat quality parameters of

venison

Red deer carcass sides suspended by Achilles tendon and pelvic bone

Chapter 6 Relationship between post-slaughter management and meat quality

parameters of venison ............................................................................................ 158

6.1: Relationship of carcass hanging time to meat quality .................................. 160

6.1.1: Introduction ............................................................................................ 160

6.1.2: Materials and methods ........................................................................... 164

6.1.3: Results .................................................................................................... 165

6.1.4: Discussion .............................................................................................. 168

6.1.4.1: Tenderness and meat ageing ........................................................... 168

6.1.4.2: Intramuscular fat ............................................................................. 169

6.1.4.3: Colour ............................................................................................. 170

Chapter Six

159

6.2: Pelvic suspension vs. Achilles tendon hanging of carcasses ........................ 171

6.2.1: Introduction ............................................................................................ 171

6.2.2 Materials and methods ............................................................................ 175

6.2.2.1 Fallow Deer ...................................................................................... 175

6.2.2.2 Red Deer........................................................................................... 176

6.2.3 Results ..................................................................................................... 177

6.2.3.1 Fallow Deer Venison ....................................................................... 177

6.2.3.2 Red Deer Venison ............................................................................ 180

6.2.4: Discussion .............................................................................................. 181

6.2.4.1: Shear force ...................................................................................... 181

6.2.4.2: Freeze-thaw purge ........................................................................... 183

6.3: Differences between slaughter premises for muscle pH ............................... 184

6.3.1: Introduction ............................................................................................ 184

6.3.2: Materials and methods ........................................................................... 186

6.3.3: Results .................................................................................................... 186

6.3.4: Discussion .............................................................................................. 187

6.4: Conclusions ................................................................................................... 188

Chapter Six

160

6.1: Relationship of carcass hanging time to meat

quality

6.1.1: Introduction

Meat tenderness has been identified by consumers as having high importance in

terms of overall meat quality (Herrera-Mendez et al 2006). Variations in meat

tenderness are a result of a combination of pre- and post-slaughter parameters,

including how meat is prepared for consumption at the consumer end (Koohmaraie

1996). The meat industry has identified a number of factors which affect final meat

tenderness, such as species, breed, age, sex and muscle type. Tenderness of meat is

determined by the amount and solubility of connective tissue, sarcomere length, rate

of proteolysis, as well as the effect of intramuscular fat and post-mortem energy

metabolism (Warner et al 2010). An understanding of the mechanisms involved in

meat tenderness allows the meat industry the scope to improve consistency in terms

of eating quality for consumers (Huff Lonergan et al 2010). Pre-slaughter

management has a significant effect on the final tenderness of the product, including

animal age and condition, finishing regime and animal handling. Post-slaughter

management techniques are also employed in order to enhance final product quality,

such as electrical stimulation, hanging technique, chilling conditions and muscle

ageing (Smulders et al 1991).

Meat ageing is defined as improvements in eating quality that occur in meat as it is

held for a period of time post-mortem (Thompson 2002). Ageing of meat is related to

enzyme activity in the muscle post-mortem, specifically enzymic degradation of

myofibrillar and associated proteins (Koohmaraie 1996). The tenderising process is

recognised as an endogenous proteolytic system related to the action of cathepsins,

the calcium dependent calpains, and the proteasomes in softening the myofibrillar

structure (Herrera-Mendez et al 2006). The role of the calpain system is undisputed,

even though the mode of action is largely unknown, however, there is some question

as to the role of cathepsins in contributing to proteolysis in the early post-mortem

period (Thompson 2002). The rate and extent of tenderising varies to a large degree,

resulting in varied tenderness of meat at the consumer end (Koohmaraie 1996). The

rate of tenderising varies with different species and has been listed in order of speed

Chapter Six

161

as pork, venison, lamb and finally beef. These data and were correlated to the rate of

glycolysis post-mortem (Smulders et al 1995). Tenderising of meat via proteolysis is

controlled by protease levels in the muscle at slaughter and the ageing time post-

rigor, as well as protease activity during post-rigor ageing (Warner et al 2010). The

action of the enzymes is dependent upon the rate of decline of pH and temperature

(Figure 5.1). Higher temperatures induce more rapid changes, and cold shortening of

a carcass can diminish the effects of enzymes on the tenderising of muscles

(Dransfield 1994). Cold shortening occurs when muscle pH is greater than 6.0 with

ATP still available for muscle contraction, and the muscle temperature is below 10

ºC (Figure 6.1) (Thompson 2002). This phenomenon is most probable in lighter

carcasses with less fat cover (Thompson et al 2006), such as young deer carcasses.

Figure 6.1 : The pH /temperature window as it relates to meat tenderness. The solid line indicates optimal decline, the dashed line cold shortening and the dotted line heat

shortening (Thompson 2002).

Studies indicate that if meat is held at temperatures slightly higher than normal

chiller temperatures, muscle proteolysis will initially be enhanced and subsequently,

meat tenderness (Dransfield 1994). However, one must bear in mind the possibility

of bacterial growth at higher temperatures, so temperatures must be as cool as

possible without freezing the meat. Recommended temperatures for long-term ageing

are -0.5 ºC to 1.5 ºC, and for short-term ageing up to 2 weeks, temperatures of 2 ºC

to 3 ºC are deemed acceptable (MTU 2010). The rate of tenderising is highest during

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162

the early stages of ageing and diminishes with time (MTU 2010). A study by Young

et al (2005) found that rapid ageing of sheep carcasses optimised eating quality when

ageing was promoted by higher temperatures (2-4 ºC).

Tenderising by ageing is also believed to reflect ultrastructural changes in the meat

structure, including separation between myofibrils and sarcolemma, with longer

storage times of 7 and 14 days resulting in more detachment in moose and reindeer

meat (Taylor et al 2001). Different muscles will respond differently to the ageing

process (MTU 2010). Those with higher levels of connective tissue will not improve

as much as those with little connective tissue (MTU 2010). Amount and solubility of

the connective tissue component is related to the age of the animal at slaughter, as

well as activity of the muscle in structure and function in the live animal (Thompson

et al 2006).

Anecdotally, the optimum length of ageing time between slaughter of an animal and

boning the carcass into commercial cuts or storage in vacuum packaging has been a

source of constant debate across all sections of the meat industry for many years.

Sanudo et al (2004) suggested that optimum ageing time depends on many factors,

including breed and age at slaughter. Given the interest in this question, it is

surprising that there has not been more extensive work done to evaluate the effect of

hanging or ageing time on meat quality parameters. Lack of chiller storage space and

interruption to cash flow have been reasons given by abattoirs and wholesalers to

limit the time between slaughter and carcass boning, while retail traders have argued

that meat quality is more important than storage costs and should dictate when

carcasses and vacuum packaged cuts are on-sold (MTU 2010). The meat industry is

full of anecdotes relating to this question and there is little evidence to support many

of the claims on the relationship between length of post-slaughter hanging times of

carcasses or storage time of vacuum packaged cuts and meat quality parameters.

Post-mortem ageing is a well recognised method utilised for the improvement of

tenderness, flavour and overall acceptability of beef. Traditionally, the methods

employed were to hang the carcass, or parts thereof, in a cool room until it was

believed to be ready to be sold to consumers. Natural loss of moisture occurred in the

uncovered carcass leading to less saleable yields. This process is known as dry

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163

ageing (MTU 2010). With the development of vacuum packaging, it was possible to

age primal cuts in a vacuum bag under more controlled conditions, leading to

increased saleable yield and the possibility of longer storage times, due to anaerobic

conditions in the pack. This method of ageing is referred to as wet ageing (Smith et

al 2008). Dry ageing is still perceived, by the premium restaurant trade, to be the

preferred method of ageing beef, leading to enhanced tenderness and flavour, where

Angus and Wagyu beef primals are often used (MTU 2010).

Even more important for the deer industry is the question of whether commercial

practices applied to carcasses from traditional domesticated species such as sheep

and cattle are appropriate for the much leaner deer carcasses. Studies on reindeer

(Barnier et al 1999; Wiklund et al 1997a) meat quality have reported that the meat is

very tender as early as 3 days post-mortem, with no significant increase in tenderness

after 7 or 14 days. The small size of muscle fibres and low collagen content in that

species is thought to be partly responsible for the tenderness, and therefore the meat

does not require ageing (Barnier et al 1999). It has also been explained by high

activity of the calpains and cathepsins (Farouk et al 2007; Wiklund et al 1997a). A

study conducted on fallow deer by Freudenreich and Fischer (1989) reported that

sensory quality was better after wet ageing for 16 days with no significant effect after

9 days. A study on red deer stags, fallow deer bucks and elk bull venison (Drew et al

1988) found that ageing at 10 ºC for the first 24 hours post-mortem, followed by up

to 72 hours at 4 ºC, resulted in improved tenderness, particularly for loin muscles

when compared with venison held at 4 ºC for the same time period .

Most of the previous studies into the effect of aging on meat tenderness have been

done by excising muscles at 1-2 days post-mortem and ageing in vacuum bags, for

periods ranging from 2 to 35 days with the average being 14 to 21 days. Studies done

on lamb (Martinez-Cerezo et al 2002; Medel et al 2002; Thompson et al 2005b; Font

i Furnols et al 2006) and beef (Campo et al 2000; Maher et al 2004; Sanudo et al

2004; Moloney 2011, Monson et al 2005; and Revilla and Vivar-Quintana 2006)

found that as ageing time increased, so did meat tenderness in a variety of breeds and

sexes. Vieira et al (2007) found that there was no real benefit of ageing up to 7 days

for yearling Spanish oxen. Studies on other species such as water buffalo (Neath et al

2007; Irurueta et al 2008), ostrich (Botha et al 2007), goats (Kannan et al 2006),

Chapter Six

164

camel (Soltanizadeh et al 2008) and reindeer (Barnier et al 1999) have found that

optimal tenderness can be achieved in as little as 3 to 5 days with no significant

difference after this time.

While wet ageing (vacuum packaging) appears to be the most common method that

has been studied, dry ageing, where the carcass is hung whole or in parts without any

protective covering, such as in the experiment conducted as part of this work, is also

used in industry for ageing of meat. A study conducted by Laster et al (2008)

compared the two methods of wet and dry ageing, and they reported that wet aged rib

eye beef steaks had lower shear force values than dry aged rib eye. However, dry

aged sirloin had lower shear force values than wet aged sirloin in that study. In

concluding, Laster et al (2008) found that there was no real significant difference

between the two methods, however saleable yields were lower with dry ageing.

This section describes an experiment designed to test whether length of carcass

hanging time post-slaughter affects the main meat quality parameters in deer

venison. The animals tested represented commercial age and body condition scores

for fallow deer of two sexes. Only one deer species (fallow deer) was tested to

minimise costs.

6.1.2: Materials and methods

Entire (n=25) and castrated (n=ll) fallow bucks (haviers) ranging from 18-24 months

old and with body condition scores ranging between 2 and 3 (lean and prime), with

average live weight of 45 kg, were fasted for 16 h and slaughtered by captive bolt

stunning and thoracic stick exsanguination within 3 seconds of the stun. All carcasses

were hung by the Achilles tendon and measured for core body temperature and

muscle pH at 1 and 24 hours post-mortem. Body condition score was measured ante-

mortem and confirmed with carcass measurements post-mortem according to the

method of Flesch et al (2002). Carcasses were hung uncovered (dry aged) in a chiller

at ±2 ºC for 5 or 10 days. LD muscles were boned out from each carcass at 5 and

then 10 days post-slaughter and divided into 3 sections, one complying with the

specified standard for mid-loin according to AUS-MEAT (1995) guidelines, one

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165

from the foreloin section (cranial end) of the muscle, and a third from the hind loin

(caudal end). These selected cuts were vacuum packaged and frozen at -21 °C for no

more than 12 weeks until analysed. Samples were analysed in triplicate for pH,

intramuscular fat, colour, shear force, moisture and freeze-thaw loss and purge. All

analyses were carried out in triplicate.

6.1.3: Results

A number of meat quality attributes for bucks and haviers are shown in Tables 6.1

and 6.2. The data show that there was no statistical difference between bucks and

castrated bucks (haviers) for intramuscular fat, meat colour lightness (L*), tenderness

and moisture content (Table 6.1). The samples from haviers had lower a* (redness)

and higher b* (yellowness) values than entire bucks after 5 days of dry ageing

(p<0.05).

Table 6.1 : Meat quality attributes of M.longissimus dorsi from fallow bucks and haviers with BCS between 2 and 3.

Sex HCW

(kg)

pHµ

Raw Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moisture

(%)

IM Fat

(%)

Bucks 25.75a

(0.94)

5.45a

(0.08)

2404.2a

(217.67)

21.27a

(0.63)

12.05a

(0.40)

0.56a

(0.39)

74.99a

(0.17)

0.73a

(0.13)

Haviers 24.69a

(0.60)

5.42a

(0.06)

2073.9a

(283.0)

19.17a

(0.50)

10.60b

(0.41)

0.80b

(0.18)

75.04a

(0.16)

0.69a

(0.17)

Means and standard error of means (in parenthesis) are shown. Treatments followed by the same letter

in the columns are not significantly different (p<0.05)

There was also no difference in moisture content for samples collected between 5

days and 10 days post-mortem. Muscle tenderness was increased after 10 days

ageing (NS) (Table 6.2).

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166

Table 6.2 : Meat quality attributes of M.longissimus dorsi from fallow bucks and haviers with BCS between 2 and 3 measured at 5 days and 10 days post-mortem.

Parameters 5 days post-mortem 10 days post-mortem

Entire bucks Haviers Entire bucks Haviers

pH 5.45 a

(0.08)

5.42 a

(0.06)

5.63a

(0.03)

5.66a

(0.02)

IM fat (%) 0.73a

(0.13)

0.69a

(0.17)

0.75a

(0.14)

0.70a

(0.16)

Colour L* 21.27a

(0.63)

19.17a

(0.50)

not analysed not analysed

Colour a* 12.05a

(0.40

10.60b

(0.28)


Colour b* 0.56a

(0.39)

0.80b

(0.18)


Shear force (g)

2404.20a

(217.67)

2073.87a

(283.02)

2364.14a

(148.34)

1996a

(128.47)

Moisture (%) 74.99a

(0.17)

75.04a

(0.16)

74.77a

(0.78)

74.95a

(0.12)

Freeze-thaw

purge (%)

17.48

(1.62)

16.97

(1.50)

16.58a

(1.51)

15.37a

(2.35)

HCW (kg) 25.75a

(0.94)

24.69a

(0.60)

25.75a

(0.94)

24.69a

(0.60)

Means and standard error of means (in parenthesis) are shown. Treatments followed by the

same letter in the rows are not significantly different (p<0.05). Not analysed - samples

destroyed following bushfire and consequent power loss to freezers

There was significantly more intramuscular fat (p<0.05) and moisture (p<0.001) in

the forequarter loin when compared with mid and hind loin samples, although there

were no significant differences between mid and hind loin. Tenderness was increased

in all loin samples after 10 days (NS) (Table 6.3).

Chapter Six

167

Table 6.3 : Mean pH, moisture, shear force and intramuscular fat measurements for fore, mid- and hind loin samples for fallow bucks and haviers measured at 5 and 10

days post-mortem.

Parameters 5 days post-mortem 10 days post-mortem

foreloin mid-loin hind loin foreloin mid-loin hind loin

pH 5.46a

(0.08)

5.52a

(0.06)

5.45a

(0.08)

5.57a

(0.02)

5.62a

(0.02)

5.63a

(0.03)

Moisture (%) 75.28a

(0.18)

74.99b

(0.17)

74.95b

(0.15)

75.46a

(0.14)

74.78b

(0.08)

74.53b

(0.16)

Shear force (g) 3168.43a

(389.32)

2404.20a

(217.67)

2244.31a

(181.94)

2310.37a

(124.54)

2364.14a

(148.33)

2095.45a

(163.13)

IM fat (%) 1.20a

(0.14)

0.73b

(0.13)

0.79b

(0.12)

1.26a

(0.11)

0.69b

(0.13)

0.75b

(0.12)


Treatments followed by the same letter in the rows are not significantly different (p<0.05).

Chapter Six

168

6.1.4: Discussion

6.1.4.1: Tenderness and meat ageing

There was no significant difference in most meat quality parameters, including

tenderness between carcasses sampled 5 days and 10 days post-slaughter, or between

entire bucks and haviers. There was a general tendency for the meat aged for 10 days

to be more tender than the 5 day aged meat, however, these differences were

statistically not significant (p>0.05). This is not consistent with findings in beef

(Destefanis et al 2003) who found no differences in meat quality attributes of steers

and bulls. Ahnstrom et al (2009) found that shear force values of yearling Charolais

heifers showed no significant differences over 7 days but were significantly more

tender after 14 days of ageing. There has long been anecdotal debate about the merits

of hanging venison carcasses longer, and the effect this has on meat tenderness, but

for animals in the current study with BCS between 2 and 3 there was no apparent

difference resulting from hanging carcasses longer. These results in fallow deer agree

with previous studies on reindeer where optimal tenderness in the meat was achieved

already after 1-3 days of ageing of the meat (Wiklund et al 1997a). A study by Shaw

(2000) also determined that venison from red deer had acceptable tenderness after

only 24 hours ageing. Studies on lamb have found that an ageing time of 20 days was

required for consumers to detect a significant difference in tenderness (Font i Furnols

et al 2006). Similarly, Freudenreich and Fischer (1989) found that wild harvested

fallow deer required at least 16 days for consumers to detect increased tenderness.

Perry et al (2001b) found that consumers ranked lamb aged for 14 days as more

tender than lamb aged for one day despite there being no significant difference in

instrumental measures of tenderness of the samples. Like fallow deer venison, water

buffalo is a low fat meat that has lower shear force values and is higher in iron and

protein than beef (Murthy and Devadason 2003). Neath et al (2007) found no

significant differences in tenderness when water buffalo meat was aged for 14 days.

However, tenderness increased in water buffalo meat after ageing over 25 days in a

study conducted by Irurueta et al (2008). Blackbuck antelope meat displayed

significant increases in pH, lower shear force values, and increased colour for all

values in meat aged for 10 days (Woodford et al 1996).

Chapter Six

169

Samples in the current study were frozen after ageing until analysed. Studies by

Drew et al (1988) found that tenderness increased 10-40% in deer venison when it

was frozen and slowly thawed. A Swedish study drew the same conclusion when

analysing shear force values of beef that had been frozen, where it was found that

frozen samples had significantly lower (p=0.005) shear force values than fresh beef

samples (MTU 2006b). This was confirmed in another study of beef where meat

aged for 2 days and then frozen had the same shear force values as chilled meat aged

for 7 days (Lagerstedt et al 2008) and similar results were reported for Korean

Hanwoo beef (Kim et al 2011). A study on lambs found that any differences

occurring as a result of freezing were small and not deemed to be significant by

consumers (Muela et al 2012). It is possible that samples were universally tender as a

result of the storage process in the current study.

Most commercial venison carcasses in Australia are broken into primal cuts between

1 and 3 days post-slaughter to avoid weight loss from dehydration in the chiller. It

would appear that commercial carcasses with BCS between 2 and 3 can be processed

at a range of times after slaughter without changing venison quality parameters, as

longer hanging times did not enhance or adversely effect parameters that are

associated with tenderness, juiciness and flavour for either of the sexes tested. This

adds considerable flexibility to commercial practice, especially given the

circumstance that deer are usually slaughtered in abattoirs primarily used for the

slaughter of other species and are operating under the commercial constraints

developed to service the wider meat industry.

6.1.4.2: Intramuscular fat

In this experiment there was no difference in intramuscular fat between entire and

castrated bucks, yet Mulley et al (1996) showed castrates to be fatter in all depots

than entires at this age, as has also been demonstrated in beef (Zhou et al 2011;

Zamiri et al 2012) from animals of the same age. Results in the current study may

just relate to animals of BCS 2 to 3, as BCS was not estimated for animals used by

Mulley et al (1996). It may also relate to poorer pasture conditions at the time of

slaughter as a result of drought. In previous studies of venison characteristics, for

most species of deer, there has been only rudimentary information given about the

Chapter Six

170

age, weight and management of the animals used to derive the data. From the data

provided by Flesch et al (2002) for fallow deer, and Audige et al (1998) for red deer

on physical and carcass differences between various BCS categories, it may be

necessary to redefine some of those meat quality measurements. In the commercial

deer industry carcass weight is a primary descriptor for payment to farmers, yet it is

possible that two animals with the same carcass weight could have very different

BCS and provide very different results for meat quality. Meat quality parameters

such as intramuscular fat, moisture, water holding capacity and possibly shear force

could change with BCS, along with changes that occur between sexes and between

seasons of the year.

The foreloin (cranial end) had significantly more fat and moisture than the mid- and

hind loin, a result consistent with the way in which fat accretion develops in other

livestock species (Butterfield 1988). These data are unlikely to be of any commercial

consequence in fallow deer given the small size of the meat cut and the way in which

this primal cut is marketed (i.e. as one whole piece, either bone-in (rack) or bone-

out).

6.1.4.3: Colour

Venison from castrated fallow deer bucks was shown to have less redness and

increased yellowness compared with entire bucks. A similar result was obtained in

fallow deer meat from castrated bucks, without ageing (Chapter 4). Similar results

were also reported for entire and castrated blackbuck antelope (Woodford et al 1996)

and goats (Kim et al 2010). Possible reasons for this may include reduced aggression

and activity in relation to adverse behavioural responses in lairage of castrated

animals. Increased muscle activity and aggression, as seen with entire male animals,

is associated with increased redness and brightness in their meat (MTU 2006a).

Given the outcomes of this study it was concluded that factors other than post-

slaughter hanging time of carcasses were more likely to effect venison quality.

However, further studies could be done utilising wet or vacuum pack ageing of cuts

over longer periods of time rather than the dry ageing methods utilised here.

Chapter Six

171

6.2: Pelvic suspension vs. Achilles tendon hanging of

carcasses

6.2.1: Introduction

Tenderness is one of the most important parameters rated by consumers in terms of

eating quality (Huff Lonergan et al 2010). Major factors which affect tenderness

include cut of meat, animal age, cold shortening that can occur during chilling and

pre-slaughter animal stress leading to high pH. Meat toughness can be reduced by the

use of techniques such as electrical stimulation, which accelerates rigor and pH

decline (Wiklund et al 2001a), or hanging the carcass in such a way that muscles will

be stretched and not allowed to contract, hence the term 'tenderstretch'. (Sorheim and

Hildrum 2002; Thompson et al 2006) (Figure 6.2).

Figure 6.2 : Diagram of pelvic suspended (left) and Achilles hung carcass (Sorheim & Hildrum 2002).

Although it is well known that the tenderness of meat can be effected by a number of

pre- and post-slaughter management techniques, optimising post-slaughter

management will assist all sections of the supply chain to deliver meat that is tender

and of high eating quality. One such post-slaughter technique is pelvic suspension or

„tenderstretch‟. Traditionally, carcasses have been suspended by the Achilles tendon

(Plate 6.1) prior to boning out. The technique of pelvic suspension has been under

Chapter Six

172

examination since the early 1970s (Hostetler et al 1970; McCrae et al 1971; Bouton

et al 1973) and has come to the forefront of the Australian meat industry via the Meat

Standards Australia grading system and the Cooperative Research Centres for lamb

and beef (Thompson 2002).

Plate 6.1 : Fallow deer carcass suspended by the Achilles tendon.

Muscles in the butt and loin of a carcass can be restrained from shortening by

hanging the whole carcass by the pelvic or aitch bone (obturator foramen) or

alternatively, the pelvic ligament (Plate 6.2).

Plate 6.2 : Fallow deer carcass suspended by the pelvic bone.

Chapter Six

173

This process increases the tension mainly on the hind and loin muscles, physically

preventing them from shortening and toughening. This technique is referred to

commercially as tenderstetching or pelvic suspension, and has been shown to

increase meat tenderness in beef (Dransfield and Rhodes 1976; Husband and Johnson

1985; O‟Halloran et al 1998; Eikelenboom 1998; Sorheim et al 2001; Hwang et al

2002; Lundesjo et al 2001; Wahlgren et al 2002; Ahnstrom et al 2006; Hwang 2006;

Park et al 2008; Wolcott et al 2009; Bayraktaroglu and Kahraman 2011; Ahnström et

al 2012), lamb (Koohmaraie et al 1996; Thompson et al 2005b; Pinheior and de

Souza 2011) and pork (Rees et al 2003; Bertram and Aaslyng 2007), as well as

several other species such as reindeer (Wiklund et al 2011), blackbuck antelope

(Woodford et al 1996) and kangaroos (Beaton et al 2001).

Carcasses are hung by either the aitch bone or pelvic ligament, though studies

indicate that as the suspension fulcrum is not the same for these two positions, the

tension on various muscles differs (Hwang et al 2002). Studies have been conducted

on a technique known as super stretching where weights are added to the hind limb

of the pelvic suspended carcass. This technique was shown not to provide any

additional benefit over conventional pelvic suspension in beef carcasses (Hopkins et

al 2000). Another technique known as tendercut involves severing the backbone and

the connective tissue along with other minor muscle attachments, which allows the

weight of the forequarter of the carcass to place tension on the LD muscle, along

with breaking of the ischium to provide tension on the hindquarter muscles. This

technique has not proven to be as effective as the pelvic suspension technique and is

more difficult to implement in a commercial setting (Wang et al 1994). Recent

developments which involve stretching and shaping meat cuts, for example

SmartStretch™ (Taylor and Hopkins 2011), are being evaluated for quality

improvement in products from sheep and lamb carcasses (Hopkins 2011) and has

been utilised successfully for beef (Sorheim et al 2001). Recent research indicates

that there is a significant interaction between stretch treatment and ageing in hot

boned mutton, resulting in lower shear force values (Toohey et al 2012a; Toohey et

al 2012b). The carcass must be held in the pelvic suspension position until chilling or

rigor mortis has been established. After this it may be rehung by the Achilles tendon

for transport or boning (MTU 2004). Carcasses may be hung as a whole carcass or

split, depending upon the size of the carcass and available chiller space (Plate 6.3).

Chapter Six

174

Plate 6.3 : Whole fallow deer carcass suspended by the pelvic bone.

Pelvic suspension reduces shortening of the myofibrils and connective matrix when

compared to hanging by the traditional method of the Achilles tendon, particularly in

the loin and hindquarter regions of the carcass. The technique increases sarcomere

length, with a resultant reduction in overlap between actin and myosin, and rapid

degradation of structural proteins at the junction of the Z disk and intermyofibre

filaments (Thompson 2002). Pelvic suspension is particularly useful for carcasses,

such as deer, that may be affected by cold shortening (Thompson et al 2006). Cold

shortening is the process whereby muscle fibres contract when the carcass is chilled

rapidly below 12 °C before the onset of rigor, and this can result in toughness in the

meat (shortened sarcomeres). Lean, light carcasses, such as deer carcasses, chill more

rapidly than fat, heavy carcasses, and can yield tougher meat in muscles that are free

to shorten (Sorheim and Hildrum 2002). The process of pelvic suspension may

adversely affect the tenderloin (M. psoas major) cut of meat because of the way this

cut contracts in the pelvic hanging position, but this change may not be detectable by

the consumer because this cut is naturally very tender and represents a very small

proportion of each carcass. There is no effect on forequarter cuts from tenderstretch

as no extra tension is applied to these muscles (Park et al 2008). Pelvic suspension, if

found to be beneficial in producing consistently tender venison, may be a useful

alternative technique to electrical stimulation in Australia, where electrical

stimulation is generally unavailable for deer processing.

The technique of pelvic suspension has also been shown to improve water holding

capacity, including drip loss, cooking loss and purge in beef (Wahlgren et al 2002;

Chapter Six

175

Ahnstrom et al 2006) and lamb (Wiklund et al 2004). This results in a more tender

and juicier product. The technique also appears to be affected by temperature or

chilling rate as described by Thompson et al (2005b) and Sorheim et al (2001) with

the largest benefits seen at fast chilling rates.

Pelvic suspension has proven to be effective in a number of meat species, however

adoption by processors has been limited. Reasons for this include alteration of the

shape of primal meat cuts, particularly in the hind limbs, thereby reducing the speed

at which operators work in the boning room, and a potential for increased space for

hanging in abattoir chillers (Hopkins 2011). Alternatives to overcome these issues

include rehanging of carcasses by the Achilles tendon after a core body temperature

of less than 7 ºC is achieved, or making use of alternative technology where hot

boned cuts are stretched and ejected into packaging which maintains the cut in a

stretched form (Toohey et al 2008).

In Australia red deer now comprise half of the national herd of deer, and yield two

thirds of the venison harvested each year (Tuckwell 2003b). The deer herd in New

Zealand, one of the largest exporters of venison, is predominantly composed of red

deer (O‟Connor 2006). Studies on red deer carcasses and venison were therefore

included in the current project to complement the fallow deer work. Even though

more scientific literature on red deer venison is available compared with reports on

fallow deer venison, the pelvic suspension (tenderstretch) technique appears not to

have been previously evaluated for red deer carcasses and venison quality. Thus, this

study provides an important comparative approach to product quality and consumer

acceptance of two types of venison, and adds valuable information to the limited

overall knowledge about this product.

6.2.2 Materials and methods

6.2.2.1 Fallow Deer

Eight fallow deer bucks (18 months old, average live weight 42 kg, body condition

score (BCS) 2-3, 7 fallow deer bucks ( 36 months old, average live weight 57 kg,

Chapter Six

176

BCS 2-3) and 10 fallow deer does (≥24 months old, average live weight 38 kg, BCS

2-4), raised at the University of Western Sydney, were included in the study. The

animals were fasted for 16 h prior to slaughter, stunned with a captive bolt and bled

using thoracic stick exsanguination within 3 s of the stun. At slaughter the hot

carcass weight was recorded, as was pH in M.longissimus dorsi (LD, strip loin) and

core body temperature. Kidneys were excised for later KFI calculations. While hot,

carcasses were split along the mid ventral axis (spine) by bandsaw and one half

randomly assigned to Achilles tendon suspension whilst the other side was hung by

pelvic suspension through the aitch bone.

At 24 hours post-mortem carcasses were weighed to determine standard carcass

weight. Ultimate pH and final core body temperature was recorded. Fat depth

measurements were taken as described by Flesch (2001) to confirm BCS post-

mortem. KFI was also calculated to confirm live animal and carcass BCS

assessments.

Nine selected muscles were collected from each carcass-half (Mm.

semimembranosus, adductor femoris, biceps femoris, semitendinosus, vastus

lateralis, rectus femoris, psoas major, longissimus dorsi, and supra spinatus). The

meat samples were vacuum packaged, and then frozen and stored at -21 oC for no

more than 12 weeks, until analysis.

Samples of LD muscles were analysed in triplicate for intramuscular fat, colour,

shear force, moisture and freeze-thaw loss and purge. The data were analysed

statistically by residual maximum likelihood (Patterson & Thompson, 1971), with

the random effects given by reading within muscle within animal, and the fixed

effects by hanging treatment, muscle and their interaction, using the statistical

package GenStat (2002).

6.2.2.2 Red Deer

Fourteen rising 2 year old red deer stags averaging BCS 2 were sourced from

properties at Blayney and Young, NSW. Body condition score was estimated on the

live animal using palpation techniques as described by Flesch et al (2002). All

Chapter Six

177

animals were slaughtered as described for fallow deer in 6.2.2.1. Skinning and

evisceration were performed with carcasses hanging from a meat rail by the Achilles

tendon. At slaughter the hot carcass weight was recorded, as was pH in

M.longissimus dorsi (LD, strip loin) and core body temperature. Kidneys were

excised for later KFI calculations. While hot, carcasses were split along the spine by

bandsaw and one half randomly assigned to Achilles tendon suspension whilst the

other side was hung by pelvic suspension through the aitch bone.

At 24 hours post-mortem carcasses were weighed to determine standard carcass

weight. Ultimate pH and final core body temperature was recorded. Fat depth

measurements were taken at the GR site with a Hennessy probe to confirm BCS

post-mortem. KFI was also calculated to confirm live animal and carcass BCS

assessments. The LD muscle from each of the carcasses was removed along with the

GM muscle, for use in sensory trials (Chapter 7). Samples removed from the

carcasses for analysis were placed on marked trays and vacuum packaged, and then

frozen at -21 C for no more than 12 weeks, until used for analysis.

Samples were analysed in triplicate for intramuscular fat, colour, shear force

moisture and freeze-thaw loss and purge. The data were analysed statistically by

residual maximum likelihood (Patterson & Thompson, 1971), with the random

effects given by reading within muscle within animal, and the fixed effects by

hanging treatment, muscle and their interaction, using the statistical package GenStat

(2002).

6.2.3 Results

6.2.3.1 Fallow Deer Venison

The results suggest that pelvic suspension of the carcasses had the greatest impact on

meat tenderness in venison from the younger male fallow deer (Figure 6.3), some

impact on tenderness in venison from the older male deer (Figure 6.4) and significant

impact only on the tenderness of the LD muscle in venison from the female deer

(Figure 6.5).

Chapter Six

178

Figure 6.3 : Shear force mean values in 7 muscles (LD = M. longissimus, BF = M. biceps femoris, ST = M. semitendinosus, SM = M. semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus femoris) from fallow bucks (18 months old,

n=8).

Figure 6.4 : Shear force mean values in 9 muscles (SS = M. supraspinatus, PS = M. psoas major, LD = M. longissimus, BF = M. biceps femoris, ST = M. semitendinosus, SM = M.

semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus femoris) from fallow bucks (36 months old, n=7).

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

LD BF ST SM AF VL RF

Muscle

Achilles

Pelvic

Shear force (kg/cm2)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

SS PM LD BF ST SM AF VL RF Muscle

Achilles Pelvic

Shear force (kg/cm 2 )

Chapter Six

179

Figure 6.5 : Shear force mean values in 9 muscles (SS = M. supraspinatus, PM = M. psoas

major, LD = M. longissimus, BF = M. biceps femoris, ST = M. semitendinosus, SM = M. semimembranosus, AF = M. adductor femoris, VL = M. vastus lateralis and RF = M. rectus

femoris) from fallow does (≥24 months old, n=10).

For fallow deer bucks, there was no interaction between body condition score and

method of hanging the carcass for all parameters measured. There were no statistical

differences between carcasses hung post-mortem by the Achilles tendon or by pelvic

suspension for the M. longissimus dorsi quality parameters of pH, colour, moisture or

fat. While there was no detectable difference of hanging method on raw muscle shear

force values (p>0.05), pelvic suspended carcasses had significantly lower cooked

shear force values than Achilles hung carcasses (p<0.001). In this experiment, no

significant differences were detected between animals of BCS 2 and BCS 3 in any of

the other parameters of meat quality, therefore data were combined for BCS 2 and

BCS 3 carcasses (Table 6.4).

Table 6.4 : Meat quality attributes of M.longissimus dorsi from fallow bucks hung by the Achilles tendon and pelvic suspension methods (n=15).

Hanging pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moist

(%)

IM

Fat

(%)

Freeze

thaw

loss

(%)

Achilles

Hung

5.80a

(0.04)

5889.5a

(341.7)

2177.4a

(115.2)

20.46a

(0.39)

12.29a

(0.52)

0.088a

(0.20)

75.70a

(0.17)

2.74a

(0.16)

13.56a

(0.98)

Pelvic

suspension

5.80a

(0.03)

4402.2b

(157.8)

2598.4a

(165.6)

21.21a

(0.55)

11.56a

(0.36)

0.117a

(0.11)

76.02a

(0.15)

3.06a

(0.24)

13.69a

(0.76)

Means and standard error of means (in parenthesis) are shown


(p<0.05).

0

1

2

3

4

5

6

7

SS PM LD BF ST SM AF VL RF

k

g

/

c

m

2

Muscle

Achilles

Pelvic

Chapter Six

180

For fallow deer does, there was no interaction between body condition score and

method of hanging the carcass for all parameters measured. Data for BCS were

analysed for differences between carcasses hung by the Achilles tendon and

carcasses hung by pelvic suspension. There was a significant difference between

methods of suspension for cooked shear (F1,16 = 7.427, p<0.01) but not for other

parameters tested (Table 6.5), with meat from pelvic suspension carcasses being

more tender.

Table 6.5 : Meat quality attributes of M longissimus dorsi from fallow doe carcasses hung by either the Achilles tendon or by pelvic suspension (n=10).

Method

suspension

pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moist

(%)

IM Fat

(%)

Freeze

Thaw

loss

(%)

Achilles

Tendon

5.73a

(0.03)

4558.6a

(217.2)

2545.9a

(277.3)

22.13a

(0.45)

13.56a

(0.39)

1.68a

(0.28)

75.49a

(0.47)

1.78a

(0.18)

16.67a

(1.04)

Pelvic

Suspension

5.69a

(0.02)

3778.6b

(155.9)

2721.6a

(271.5)

22.24a

(0.43)

13.56a

(0.37)

1.68a

(0.35)

74.35a

(0.28)

1.89a

(0.17)

13.76a

(1.08)

Means and standard error of means (in parenthesis) are shown


(p<0.05).

6.2.3.2 Red Deer Venison

There was a significant difference between carcasses hung by the Achilles tendon

compared with pelvic suspension for cooked shear (F1,26 =16.204, p<0.001) but not

for other parameters tested (Table 6.6), with meat from pelvic suspended carcasses

being more tender.

Chapter Six

181

Table 6.6 : Meat quality attributes of M. longissimus dorsi from red stags hung by the Achilles tendon or pelvic suspension after slaughter (n=14).

Method of

Hanging

pH Cooked

Shear

(g)

Raw

Shear

(g)

Colour

L*

Colour

a*

Colour

b*

Moist

(%)

IM

Fat

(%)

Freeze

Thaw

loss

(%)

HCW

(kg)

Achilles

tendon

5.63

(2.67)

5475.78 a

(298.13)

3535.01 a

(184.00)

23.01 a

(0.39)

11.44 a

(0.35)

2.96 a

(0.22)

75.95 a

(0.14)

1.72 a

(0.28)

12.06 a

(0.67)

51.56

(2.67)

Pelvic

Suspension

5.63

(2.67)

4124.12 b

(154.49)

3761.80 a

(167.87)

23.19 a

(0.28)

11.80 a

(0.21)

3.05 a

(0.15)

75.96 a

(0.20)

1.47 a

(0.22)

10.39 a

(0.57)

As

above



(p<0.05).

6.2.4: Discussion

6.2.4.1: Shear force

The technique of hanging carcasses by the pelvic or aitch bone („tenderstretch‟)

instead of in the usual position by the Achilles tendon resulted in more tender meat in

the M. longissimus dorsi (strip loin) for fallow deer bucks, fallow deer does and red

deer stags. In the Australian beef grading system Meat Standards Australia (MSA),

consumer important sensory quality attributes have been weighted in an overall score

where tenderness represents 40%, flavour 20%, juiciness 10% and overall liking 30%

(MSA 2001). It is well known that the conditions during rigor development (e.g.

muscle pH decline, temperature/pH relationship and carcass treatment) are very

important in controlling meat tenderisation (Dransfield 1994). Therefore, carcass

suspension techniques have been studied for beef (Hostetler et al 1970; Lundesjö

Ahnström et al 2003; Ahnström et al 2012) where the variation in tenderness is

considered to be the main reason for consumer dissatisfaction (Koohmaraie 1996).

Results similar to the current study were shown in beef, where the pelvic suspension

technique generally improved tenderness in most of the studied muscles, but

responses to suspension method were inconsistent and differed by muscles and

genders (bulls, heifers and cows) (Lundesjö et al 2005; Ahnström et al 2012). The

tenderness in meat from bulls was increased as an effect of pelvic suspension

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compared with meat from the heifers (Fisher et al 1994; Lundesjö Ahnström et al

2003). Pelvic suspension was also found to increase tenderness of meat from Bos

indicus cattle (Wolcott et al 2009), hybrid Charolais heifers (Ahnström et al 2009),

non-electrically stimulated bulls (Sorheim et al 2001) and cull ewes (Pinheiro and de

Souza 2011).

In the carcasses from the young fallow deer bucks, the tenderness of the following

muscles was significantly improved (p0.05) as a result of pelvic suspension; Mm.

longissimus, biceps femoris, semimembranosus, adductor femoris and vastus

lateralis. These results are in good agreement with earlier studies on beef, where the

tenderness of Mm. longissimus, semimembranosus and adductor femoris was

increased by pelvic suspension (Hostetler et al 1970; Bouton et al 1973). For the

older fallow deer bucks, significant effects of pelvic suspension on meat tenderness

were found in Mm. biceps femoris and semimembranosus. The muscles that

increased in tenderness as a result of pelvic suspension in the present study are

considered the most valuable cuts in a deer carcass, i.e. M. longissimus (strip loin),

Mm. semimembranosus and adductor femoris (topside), M. biceps femoris

(silverside) and M. vastus lateralis (knuckle). The fallow deer does only showed

improvement in tenderness for Mm. Longissimus. There was no significant effect on

forequarter muscles, as is the case for beef (Park et al 2008). It was noted by

Thompson (2002) that poorer eating quality beef carcasses showed the greatest

response to pelvic suspension, as did Sorheim et al (2001), so it is not surprising that

already tender and high eating quality meat from fallow deer does was not as

significantly affected as that from fallow deer bucks and red stags.

Studies in beef (Hwang et al 2002) also found that pelvic suspension resulted in

longer sarcomeres and more tender meat for most hindquarter muscles when

compared to Achilles hanging. The effect was most significant in the Mm.

semimembranosus, longissimus dorsi, gluteus medius, biceps femoris and the vastus

group. As was the case in the current study, the tenderloin or Mm, psoas major was

allowed to shorten as a result of pelvic suspension, however, the decrease in

sarcomere length was small and did not significantly affect tenderness of this already

tender muscle.

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6.2.4.2: Freeze-thaw purge

There was no significant difference in the freeze-thaw purge losses in pelvic

suspended carcasses versus Achilles hung carcasses. It has been documented,

however, that water holding capacity in fresh, chilled beef is improved by pelvic

suspension of the carcass (Eikelenboom et al 1998; Ahnström et al 2006), while

other studies have found no significant effect (Bayraktaroglu and Kahraman 2011).

Wiklund et al (2004) reported that drip loss was significantly lower in fallow deer

venison that had been suspended by the Achilles tendon, however, vacuum package

purge was lower in pelvic suspended samples stored for 3 weeks.

The positive effect of pelvic suspension on tenderness in venison from young male

fallow deer and young red deer stags is important information to consider for the

Australian and New Zealand deer industries. This type of animal represents the deer

most likely to be supplied for commercial slaughter in Australia and New Zealand. In

addition, the important commercial cuts from female deer were generally more

tender than the same cuts from males. The slaughter of female deer therefore

provides a good option for farmers wishing to supply chilled venison year-round,

especially at times of the year when the quality of venison from male deer is

negatively affected by the breeding season.

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6.3: Differences between slaughter premises for

muscle pH

6.3.1: Introduction

Animals store glycogen in the muscle for energy that is used to support general body

function (Thompson 2001). Prior to slaughter animals may metabolize these energy

stores when dealing with stressors that occur with handling, transportation and

lairage. If an animal is severely stressed it may deplete the energy stores in the

muscles. Ferguson et al (2001) state that in relation to optimal meat quality, pre-

slaughter depletion of glycogen stores is unequivocally the most critical parameter.

Utilisation of glycogen stores (glycogenolysis) is believed to occur as a result of an

increase in activity and adrenal activation.

It is well known that muscle energy (glycogen) is required during the conversion of

muscle to meat, post-slaughter. When an animal is slaughtered the muscle continues

to metabolise glycogen stored in the muscle in a process known as glycolysis.

Glycolysis results in the production of lactic acid, thereby reducing muscle pH. The

rate at which glycolysis occurs is temperature dependent. The process of glycolysis

causes the muscle pH to decrease. In a live animal muscle pH is fairly neutral (7.1)

and optimal pH of meat is within the range of 5.3 to 5.6. This ultimate pH is

achieved when the carcass temperature falls below 7 ºC or at around 20 hours post-

slaughter and energy stores have been exhausted. If energy stores are insufficient at

slaughter, then insufficient lactic acid is produced during glycolysis and pH will be

high (Aberle et al 2001).

The negative impact and incidence of high muscle pHu on meat quality is well

documented in the major meat species, beef (Hood and Tarrant 1981; Thompson

2002) and lamb (Koohmaraie 1996, Thompson et al 2005b; Young et al 2005). It has

also been tested in buffalo (Neath et al 2007); gemsbok (Hoffman and Laubscher

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2010); fallow deer (Falepau 1999; Diverio et al 1998); red deer (Pollard et al 1999,

Stevenson-Barry et al 1999); and reindeer (Rehbinder, 1990; Wiklund 1996b;

Wiklund et al 1997b; 2003a).

Venison with high pH has undesirable characteristics, as is the case with other meats,

with a decreased shelf life as one of the major problems. The high pH will promote

microbial spoilage, an effect which is especially critical for vacuum packaged meat.

Meat with high pH is generally referred to as DFD (dry, firm and dark). The

frequency of occurrence of DFD (meat pH above 6.2 in M. longissimus dorsi) in

venison has been reported in Sweden (reindeer, n=3,500, Wiklund et al 1995) and

New Zealand (red and fallow deer, n=3,600, Pollard et al 1999) as 6% in reindeer,

1.5% in red deer and 1% in fallow deer venison. Higher pH values also often result

in less tender meat in beef (Purchas et al 1999), lamb (Watanabe et al 1996) and red

deer venison (Stevenson-Barry et al 1999; Wiklund et al 2010).

Stress is an unavoidable consequence of the process of transferring animals from the

farm to slaughter (Ferguson and Warner 2008). Meat Standards Australia (MSA)

have set criteria for supplying cattle to minimise pre-slaughter stressors and

subsequent depletion of muscle glycogen reserves. These criteria include adequate

feeding of cattle up until dispatch to ensure muscle glycogen levels are between 60

and 120 µmol/g. This ensures levels of muscle glycogen at the time of slaughter are

at least 57 µmol/g so that sufficient lactic acid may be formed to lower muscle pH

from around 7.1 in the live animal to 5.5 post-mortem. Short term stress can increase

the capacity of the muscle to decline in pH while long term stress can reduce it.

Muscle glycogen is depleted by stress through the action of adrenaline and

β2=adrenoreceptor densities (Oddy et al 2011). Stressors that need to be controlled to

minimise fluctuations in the emotional state of the animal are transport distances and

lairage conditions involving handling and human contact, unfamiliar environments,

fasting, changes in social structure as a result of mixing and/or separation of animals

and changes in climate (Thompson 2002; Ferguson and Warner 2008).

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6.3.2: Materials and methods

Entire (n=32) fallow bucks ranging from 18-24 months old and with body condition

scores ranging between 2 and 3 were slaughtered at three different slaughter

premises. One group (n=8) were slaughtered as described in Chapter 3 at the

University experimental abattoir. One group (n=12) was slaughtered at a domestic

commercial works using the slaughter technique described in Chapter 3. The final

group (n=12) were slaughtered at an export commercial works using the reversible

electric stun and gash cut method (Mulley and Falepau, 1999). All deer were

slaughtered at similar ambient temperatures, in the same month. Carcasses were

measured for pH and core body temperature at 1 and 24 hours post-slaughter.

6.3.3: Results

There was a significant difference between slaughter plant 3 (export) and the other

two premises examined (Table 6.7). This trial indicates that captive bolt stunning and

thoracic stick exsanguination resulted in carcasses with significantly lower ultimate

pHu values. Animals held in lairage at the export works were subjected to stresses

and noise from working dogs, and cattle and sheep held in close proximity. Slaughter

plants 1 and 2 were used exclusively for deer with no dogs present.

Table 6.7 : Ultimate pH of M.longissimus dorsi from fallow bucks slaughtered at three different slaughter plants.

Slaughter

Premises pHu

Abattoir 1 (UWS)

5.52a (0.05)

Abattoir 2 (Domestic)

5.80a (0.02)

Abattoir 3 (Export)

6 09b (0.09)

Means and standard error of means (in parenthesis) are shown. Treatments followed by the same letter in the columns are not significantly different (p<0.05).

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6.3.4: Discussion

In this experiment it was demonstrated that the prolonged pre-slaughter handling in

connection with slaughter at an export abattoir resulted in higher venison pH values.

Stress before slaughter can induce muscle glycogen depletion so meat pH stays

above 6.2 and DFD meat occurs. In a similar study, muscle glycogen was found to be

the highest and optimal pHu was achieved in fallow deer where animals were shot in

the paddock, thereby avoiding any handling prior to slaughter (Mojito et al 2007).

The next best result was obtained in animals that were moved into lairage and

processed without delay. The groups which resulted in the highest incidence of high

meat pH and DFD meat and lowest muscle glycogen levels was in the group where

animals were held in lairage overnight prior to slaughter as is the normal practice

with venison processing in Australia (Mojito et al 2007).

There are numerous studies in beef (Purchas and Aungsupakorn 1993), lamb (Bouton

et al 1971) and pork (Dransfield et al 1995) that have linked variation in ultimate

muscle pH and its relationship to meat tenderness. These studies concur that as pH

increases from 5.5 to 6.0, instrumental tenderness decreases. A study by Yu and Lee

(1986) suggests that proteolysis is reduced at higher pH levels, thereby reducing

tenderness. In red deer, a study by Stevenson-Barry et al (1999) reported that optimal

tenderness was achieved at a pH value of 5.5 with greater variability in tenderness in

the pH range of 5.8 to 6.0. This was confirmed by Hoffman et al (2007) in a study on

springbok, where an increase of ultimate pH from 5.5 to 5.9 resulted in increased

shear force values.

As the New Zealand red deer industry was being established, the use of a mobile

slaughter plant was trialled in order to reduce pre-slaughter handling and thereby

minimise the incidence of high pH in venison (Yerex 1979). However, its use was

soon dismissed as an option because it proved to be economically impractical

(Seamer 1986). More recently, mobile plants for deer have operated in Canada

(Diversified Animal Management, 1997), the UK (Anon 1993; Pollard et al 2002)

and Australia (Mulley 2011). Mobile slaughter facilities have been used for reindeer

in Sweden since 1993. When new directives regarding meat inspection at reindeer

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slaughter were instituted (National Food Administration 1998), many of the former

outdoor slaughter sites were closed and the numbers of reindeer transported to

slaughter increased (Wiklund 1996b). Slaughter age reindeer bulls exhibited lower

pHu values when handled carefully and transported for less than 5 hours compared to

bulls manually handled and transported over larger distances (Wiklund et al 2001a).

According to Wilson (1999), regular handling of deer can reduce the occurrence of

pre-slaughter stress since it improves the animals‟ ability to cope with management

practices. Selection of tamer and calmer breeding animals is also an important

measure to reduce stress (Wilson 1999). These practices should be implemented in

particular for fallow deer, since it has been demonstrated that they require very

careful, slow handling and are prone to panic (Diverio et al 1998; Pollard et al 2002).

6.4: Conclusions

Pelvic suspension of carcasses has been demonstrated to improve tenderness in meat

from young fallow deer bucks, older fallow deer bucks and does as well as young red

stags, the type of animals most likely to be supplied by deer farmers for commercial

slaughter in Australia. Results for fallow deer of different BCS, age and sex, and for

red deer, also indicate that pelvic suspension increases the tenderness of venison, the

quality attribute determined by consumers as being of most importance. Given the

consistency of this result and the importance of meat tenderness in the meat retail

sector, this technique should be adopted by the Australian deer industry, especially

given the low availability of other techniques associated with increasing meat

tenderness such as electrical stimulation. If electrical stimulation of carcasses were

to become more widely available in slaughter premises in Australia, it would also be

interesting to trial the techniques of pelvic suspension and electrical stimulation of

carcasses in combination to evaluate possible cumulative effects. Studies in lamb and

mutton by Young et al (2005) determined that electrical stimulation was not required

when pelvic suspension techniques were utilised, however, Thompson et al (2006)

found a cumulative effect when pelvic suspension was combined with other post-

slaughter management techniques for optimising tenderness.

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The present results also indicate that pelvic suspension has a positive effect on

water-holding properties by reducing moisture loss of fresh chill-stored fallow deer

venison, an important consideration given that juiciness is the second most important

characteristic of meat according to consumer surveys. Most venison produced is sold

frozen (Wiklund et al 2004), and in this study freeze-thaw losses were unaffected by

suspension method.

In both fallow deer and red deer venison pelvic suspension is an inexpensive and

reliable way to improve venison tenderness and palatability. The perceived

disadvantages in terms of labour and chiller capacity in a commercial setting are not

significant in terms of the potential for improved eating quality of venison from red

and fallow deer. It is possible to achieve similar levels of tenderness in fallow deer

bucks as fallow deer does by employing pelvic suspension techniques.

In these experiments it was also demonstrated that there is no commercial advantage

in hanging fallow deer carcasses for extended periods of time after slaughter to

increase tenderness, a technique that has been applied to carcasses from older

animals harvested from the wild in other parts of the world. Analysis of data from

this study indicated that carcasses from deer farmed commercially and slaughtered

for meat can be broken into primal cuts using the same time periods used on

carcasses from sheep and cattle with no loss of eating quality. This is an advantage

to the deer industry because no special longer-term storage requirements are

therefore necessary.

Minimising pre-slaughter stressors is also vital to ensure venison of ideal ultimate pH

and therefore, optimise meat quality.

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Chapter Seven

Effect of pre- and post-slaughter management

on the sensory parameters of venison quality

Venison dish

Chapter 7 Effect of pre- and post-slaughter management on the sensory parameters of venison quality ............................................................................... 190

7.1: Introduction .................................................................................................. 191 7.2: Materials and methods ................................................................................. 198

7.2.1: Sensory evaluation facility ..................................................................... 198 7.2.2: Panellists ................................................................................................ 198 7.2.3: Sample preparation ................................................................................ 198 7.2.4: Sample testing ........................................................................................ 199 7.2.5: Data analysis .......................................................................................... 200

7.3: Results and discussion .................................................................................. 201 7.3.1 Fallow deer (pasture-fed) ........................................................................ 201

7.3.1.1 Experimental design ......................................................................... 201 7.3.1.2 Results .............................................................................................. 201 7.3.1.3 Discussion ........................................................................................ 205

7.3.2: Fallow deer - Impact of Supplementary Feeding ................................... 208 7.3.2.1 Introduction ...................................................................................... 208 7.3.2.2 Experimental design ......................................................................... 209 7.3.2.3 Results .............................................................................................. 210 7.3.2.4 Discussion ........................................................................................ 212

7.3.3 Red Deer (pasture-fed) ............................................................................ 215 7.3.3.1 Introduction ...................................................................................... 215 7.3.3.2 Experimental design ......................................................................... 216 7.3.3.3 Results .............................................................................................. 217 7.3.3.4 Discussion ........................................................................................ 221

7.4: Conclusions ................................................................................................... 223

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7.1: Introduction

One of the primary objectives of the red meat industry has been an attempt to deliver

consistently high quality meat to consumers (Grunert et al 2004). Eating quality has

long been recognised as a determinant for repeat purchasing by consumers (Watson

et al 2008) and many forms of assessment are utilised to gauge a good eating

experience by the consumer. These include measurement of pre- and post-slaughter

parameters and physical measures of the meat such as shear force, water holding

capacity and colour values. Though one dimensional, these measures attempt to

predict various aspects of the eating experience of consumers, however, the ultimate

way of testing the product is to place it with a consumer panel (Russell et al 2005,

Watson et al 2008). Sensory evaluation is the science of judging and evaluating the

quality of food by using some or all of the senses, for example, taste, smell, sight,

touch and hearing. Human beings have always used their senses for guiding their

choice of food (Meilgaard et al 2007). Our senses are used to evaluate the quality of

food, and although science has developed objective measures to assess food quality,

they cannot replace the use and sensitivity of the human senses (Poste et al 1991).

A sensory evaluation is generally based on the qualities of the food characteristics,

both acceptable and unacceptable, which are sensed by the consumer or taste

panellist. These general characteristics are normally appearance, flavour and texture

but can be divided further into colour, aroma, taste, tenderness, juiciness and mouth

feel. For red meats, consumers generally rank these attributes, with tenderness being

the most important, followed by juiciness (Issanchou 1996).

A number of studies have been done to link physical and biochemical measures of

meat from domesticated livestock to consumer preference. A range of objective meat

quality measurements, including water-holding capacity and colour as well as

chemical and nutritional composition of meat, have been related to sensory attributes

of a range of domesticated species including beef (Egan et al 2001; Perry et al 2001b;

Thompson 2002; Lagerstedt et al 2008; Yadata et al 2009), lamb (Sanudo et al 1998;

Martinez-Cerezo et al 2002; Hoffman et al 2003; Hopkins et al 2005; Pethick et al

2005a; Pleasants et al 2005; Thompson et al 2005b; Mushi et al 2008), goat meat

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(Carlucci et al 1998, Mushi et al 2008) and pork (Aaslyng et al 2007; Bertram &

Aaslyng 2007; Lloveras et al 2008). Tenderness of beef has been tested for consumer

preference in a number of studies. (Rosenvold et al 2002; Voges et al 2007; Sawyer

et al 2007; Destefanis et al 2008; Hildrum et al 2009; Rodas-Gonzalez et al 2009)

and Thompson (2002) found a high correlation between tenderness and overall liking

in beef samples, but it appears similar studies have not been done with fallow deer

venison.

The sensory quality of venison has not been studied extensively but some research

has reported various meat quality and sensory attributes of red deer (Wiklund et al

2003b) and reindeer (Wiklund et al 2003a). Sensory evaluation studies have been

conducted on some other game species including kangaroo (Wynn et al 2004),

buffalo (Vasanthi et al 2007), springbok (Hoffman et al 2007), camel (Dawood

1995), ostrich (Hoffman et al 2008a), horse (Sarries & Berlain 2005), rabbit (Combes

et al 2008) and feral goats (Swan et al 1998), while Rodbotten et al (2004) developed

a sensory map of 15 species, both domesticated and non-domesticated. The deer

venison included in that study was from wild reindeer, moose and roe deer. They

noted that these species along with beaver, farmed goat and hare were identified as

having the most intense gamey flavour, whilst chicken, turkey, pork and veal had

little perceived flavour. Lamb, roe deer, moose and hare were identified as being the

most tender. A number of sensory studies on meat have been undertaken but none

with a particular focus on venison in relation to pre- and post-slaughter handling and

body condition.

Consumer panellists may be either trained or untrained. A trained panel will be

comprised of fewer panellists compared with untrained panels, and all members of a

trained panel will have attended a number of familiarisation sessions enabling them

to detect specific quality aspects of the meat to be tested (Perry et al 2001a; Hansen

et al 2006; Combes et al 2008; Hoffman et al 2008; Watson et al 2008). Due to the

small number of panellists in trained panels, bias may be introduced as a result of the

training process as well as demographic variations of panel members who may not

represent the wider population (Hwang et al 2008). However, trained panellists are

generally adept at scoring very specific attributes (Thompson 2002). Untrained

consumer panels are comprised of a larger number of panellists and are generally

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193

used for simple consumer preference or comparative testing (Hopkins et al 2005;

Polkinghorne et al 2008a, Thompson et al 2005b). In other studies (Wheeler et al

2004; Lagerstedt et al 2008) a semitrained panel was used where a larger number of

consumer panellists had attended a small number of familiarisation sessions for

detection of a range of flavour and other quality attributes. As described by Munoz,

(1998) consumers for quantitative, descriptive analysis should be “naïve users” or

potential users of the product who are carefully recruited, not panellists who have

been trained to evaluate products in a laboratory. The number of panellists in those

studies needed to be larger than in studies using trained panels in order to produce

valid results. Poste et al (1991) described panels that fell into one of four categories:

(i) highly trained experts consisting of between one and three people; these types of

panels are used where a high degree of acuity is required and mostly found in the

wine, tea and coffee industries (ii) trained panels of between 10 and 20 people used

for assessing product attribute changes (iii) laboratory acceptance panels of between

25 and 50 people; these are valuable in determining consumer acceptance or

descriptions of products (iv) larger panels of over 100 people, which are largely used

to determine general consumer preference and reaction to products without specific

descriptors. A review of related literature highlights the highly variable nature of the

panel type utilised in meat studies. Panels vary from large untrained consumer panels

involving many hundreds of panellists (Hopkins et al 2005); smaller numbers, under

100, of semi-trained panellists (Lagerstedt et al 2008); through to small trained

panels of under 10 panellists (Wilkund et al 2009).

Sensory evaluation can be viewed as a science that uses people as instruments. The

human senses are influenced by external physical and psychological factors or

biases, and these external factors need to be controlled or minimised in order to

achieve accurate and repeatable results. Meat as a biological product presents many

challenges for evaluation studies of sensory attributes. Unlike a processed product,

raw meat is not uniform. Primal cuts may vary in flavour from one end to the other,

and there can be great variation between samples (Munoz 1998). Achieving similar

end point temperatures during preparation can also be difficult across the entire cut

for the purpose of sensory evaluation techniques.

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Descriptive analysis is used to identify sensory characteristics that are important in a

product and to produce information on the degree of intensity of those

characteristics. This type of analysis allows quantitative studies of meat samples to

be linked to, and provide additional information on, meat quality from biochemical

analysis (Munoz 1998). As success of food products is determined by consumer

acceptance, it is important to measure consumer perceptions of a range of meat

quality attributes to ensure repeat purchase of meat products.

It is important to present samples to the appropriate target market for evaluation.

Little literature exists which identifies target markets for consumers of Australian

venison, even though the deer industries in New Zealand and Australia have

established export markets in Europe. At the commencement of the deer farming

industry and today, much of the venison produced in Australia and NZ is exported to

Western Europe and Scandinavia where it is considered a traditional product

(O‟Connor 2006). However, recent approaches by Australian and New Zealand chefs

have promoted a more contemporary style of cooking farmed venison. Research by

the deer industry in New Zealand has shown emerging market niches in younger

consumers and households with high disposable income (O‟Connor 2006). These

markets seek lighter, healthier menu options with premium quality and convenience.

Markets are also being established in Asia (O‟Connor 2006).

The palatability of a food product largely determines whether a consumer chooses to

include that product in their diet, though factors such as price, availability and

cultural acceptability will also influence whether particular products are consumed

regularly. Current consumers are more health conscious and demand meat that is of

high quality (Thompson 2002), and the success or failure of food products is driven

by consumer acceptance. Meat quality is an area of increasing consumer focus, with

various grading systems in place throughout Australia and the rest of the world.

These systems, such as Meat Standards Australia (MSA), have evaluated consumer

acceptability for beef and lamb products (Thompson 2002). For meat products the

characteristics of palatability most commonly referred to by consumers are

tenderness, juiciness and flavour, though it is likely that considerable variation exists

between consumers as to which part of this combination contributes most to their

eating experience. Various machines and laboratory assays can quantify individual

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195

characteristics of meat, but the palatability or overall liking is an imprecise science

that can only be measured by consumers, varies between consumers, and combines

several characteristics in its appraisal (Aberle et al 2001). Variation in any one

characteristic can alter the palatability mix and change the overall liking.

There are many areas in the value chain from paddock to plate that can affect

palatability and these need to be standardised, where possible, for sensory evaluation

to be informative. The age of an animal, husbandry and management, slaughter

techniques and post-slaughter carcass storage can all be standardised, therefore

cooking technique and cut of meat must also be standardised for sensory evaluation

work to be meaningful and comparative. Variations in cooking technique between

consumers can alter the perception and palatability of meat (Aberle et al 2001;

AMSA 1995), so for comparative sensory analysis of product between consumers the

cooking technique must be standardised, as described in the general materials and

methods section of this document. Although the cooking technique applied to

sensory work is different in some cases to that which would be applied commercially

(eg. the charcoal layer of steak cooked on a hot plate, or embellished flavours from

marinades and sauces, are missing), the ability to compare tenderness, juiciness and

natural flavour in a standardised way between samples is retained.

There is considerable literature on the impact of animal age and cut of meat on meat

quality (Berg and Butterfield 1976; Butterfield 1988; Lawrie and Ledward 2006;

Aberle et al 2001; Rodbotten et al 2004), particularly tenderness. Although muscles

of very young animals are more tender than those of aged animals (Aberle et al

2001), changes occurring with age are not linear with increasing age (Butterfield

1988). As animals grow, muscle growth and fat deposition occur at different rates,

producing considerable variation within the carcass depending on when the animal is

slaughtered. During rapid phases of growth, tenderness increases with time because

rapid development of muscle fibre size reduces the relative effect of existing

connective tissue on muscle fibre bundles. Thus, market weight beef animals (12 to

18 months of age) often have more tender meat than growing calves (6 months of

age) (Aberle et al 2001). This is also likely to be the case in deer although there is no

evidence based on experimental work to support this.

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Aberle et al (2001) also contend that beef flavour intensifies as animals get older and

carcass maturity and marbling increases. They suggested that the likely cause of

flavour change with increased age is due to an increase in concentration of

nucleotides in muscle, which degrade to inosinic acid and hypoxanthine post-

mortem. Flavour intensity may become so great that it is objectionable to some

consumers, an example being the strong mutton flavour of mature sheep or meat

from game animals.

As animals mature, body composition ratios of muscle:bone:fat occur (Butterfield

1988), with body fat deposition (intramuscular and intermuscular) increasing

proportionately to muscle and bone under normal growth patterns. The relationship

between slaughter weight, fat content and some quality attributes has been

established for some meats such as beef (Correale et al 1986), lamb (Tejeda et al

2008) and rabbit (Carrilho et al 2009), but has not been considered as important with

deer venison because the leanness of venison is considered to be an important

marketing strength. However, linkage of BCS with animal age can assist with

standardising physical (cut size, tenderness) and biochemical (flavour, colour)

characteristics once consumer preference is known, in addition to providing

important information on the husbandry and management of animals pre-slaughter.

In the current study, as described in Chapter 5, it was evident that slaughter-aged

(12-24 months) fallow deer are usually in the BCS range 2-3, though older animals

can reach BCS 4-5 seasonally or when fed concentrates.

Body condition score is a useful tool in assessment of animal nutritional status, and a

frequently used descriptor in the buying and selling of livestock for slaughter (Flesch

et al 2002). Market specifications are often established according to the amount of

subcutaneous fat coverage (Gaden et al 2005) on the live animal and scales of

reference have been established that allow accurate prediction of carcass

characteristics from live animal BCS assessments in fallow (Flesch et al 2002) and

red deer (Tuckwell 2003b). As previously described, the level of fatness in a carcass

can be estimated by using BCS as an indicator. Often the only guide to whether an

animal is suitable for slaughter is its live weight and general body condition, and for

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this reason the present study was developed to evaluate whether BCS per se was

related to consumer preference for fallow or red deer venison.

Venison from fallow deer carcasses hung by pelvic suspension has been shown to be

consistently more tender than venison from carcasses hung by the Achilles tendon

(Sims et al 2004), and this improvement to product quality has been demonstrated

across different sex and age classes of fallow deer. The technique of PS is now used

commercially for carcasses from domestic species like beef and lamb, especially

within quality control systems that guarantee a tender product (Meat Standards

Australia, 2001). The effect of pelvic suspension as an alternative carcass suspension

technique on meat quality has not been reported for red deer prior to this study.

Previous chapters have described meat quality attributes and physical characteristics

commonly measured for meat, and post-slaughter carcass management that can

influence some of those measurements. This section describes sensory analysis of

venison from red and fallow deer using consumer preference tests. The data are

arranged separately for fallow deer and red deer.

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198


7.2.1: Sensory evaluation facility

The University of Western Sydney‟s sensory evaluation laboratory consists of six

individual booths designed to minimise suggestion, effect or influence by other

panellists. The booths are serviced by a preparation area. The room was kept at a

constant 22 ºC during tastings with uniform fluorescent lighting. The design of the

facility is consistent with ISO guidelines (2007).

7.2.2: Panellists

Descriptive and consumer preference (affective) sensory testing was undertaken with

42 panellists (Meilgaard et al 2007) who were recruited via newspaper advertising

and email. All procedures for recruitment of panellists and testing of samples were

approved by the Human Ethics Committee of UWS (number HEC 03-206). There

was an even distribution of males and females with ages ranging from 25 to 55 years.

Panellists were screened to determine if they were eaters of red meat and were

willing to try venison, or were current venison consumers. Consumers were also

screened to ensure they preferred meat cooked to medium doneness. Panellists who

smoked were asked to refrain from smoking one hour prior to and during the

sessions. Panellists undertook familiarisation and training sessions as recommended

by ISO (1993), and as described by AMSA (1995), to assist in identifying quality

parameters for venison such as liver and game flavours, colour, tenderness, juiciness

and use of the survey tool.

7.2.3: Sample preparation

Frozen samples were transferred to a cooling chamber, with a temperature of 5 ºC, 24

hours prior to analysis. Samples were prepared in unsealed vacuum packages

immersed in a water bath for 60 minutes, to reach an internal temperature of 67 C.

(Wiklund et al 1997b; AMSA 1995) which was shown to produce a product which

remains palatable and safe for consumption (Rodbotten et al 2004). Both the water

Chapter Seven

199

bath and sample were monitored closely for temperature levels using a digital probe

thermometer. Samples were removed from the water bath and immediately sliced

into 5 mm thick slices and served to panellists, without delay. All meat samples

tested were from the M.gluteus medius (rump).

7.2.4: Sample testing

Panellists were presented with a sample identified by random three digit codes (to

minimise expectation error) and answered questions on the descriptive test by

indicating on an unstructured line scale (0 low intensity) (11 high intensity) how they

rated the sample for flavour, colour, juiciness, tenderness and overall liking

(Appendix 4). Samples were presented on white plates in statistically randomised

order. Panellists were asked to taste up to six samples at each session, and attended

four sessions to complete the work in order to avoid palate fatigue. Each session

lasted 30 to 45 minutes, and a 15 minute break was given half way through each

session for the same reason. Panellists were seated in individual booths (Plate 6.1)

with a drinking cup containing water (90%) and apple juice (10%) to cleanse the

palate between samples. Sessions were conducted mid-morning and early afternoon.

Plate 7.1 : Panellist in individual tasting booth.

Panellists were grouped according to gender (males n=21) (females n=21), age

group, and whether or not they had previous game meat eating experience (previous

experience n=27) (no experience n=15) for the purpose of analysis. Ages were

Chapter Seven

200

grouped as follows: age group 1 (25-34 years n=14), age group 2, (35-44 years n=13)

age group 3 (45-55 years n=15).

The panellists were asked to evaluate samples to determine any differences between

samples due to differences in BCS, sex, post-slaughter suspension method and

feeding regime.

Venison samples were examined for microbial safety prior to and after presentation

to panellists, then frozen and stored for 6 months after completion of the tests.

7.2.5: Data analysis

Score sheets were measured by two assessors using vernier callipers, and the data

recorded as described by Thompson et al (2005c). Data were analysed using SPSS

11.5 analysis of variance using the GLM procedure. All fixed effects and their

interactions were tested in the same model. If the treatment effect was significant,

treatment means were separated using Ryan‟s Q test (SPSS 2002).

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201

7.3: Results and discussion

7.3.1 Fallow deer (pasture-fed)

A series of experiments were performed to investigate the effect of BCS, sex of the

animal and method of post-slaughter carcass management on sensory perception of

fallow deer venison quality by consumers.

7.3.1.1 Experimental design

Intact (n=20) fallow bucks ranging from 18-24 months old, and non-pregnant fallow

does (n=10) approximately 36 months old with a history of one previous lactation, in

the BCS range of 2 and 3 (lean and prime), were killed by captive bolt stunning and

thoracic stick exsanguination within 3 seconds of the stun. All fallow deer were

raised on pasture. All carcasses were split along the spine before chilling, with one of

the sides randomly allocated to be hung by the Achilles tendon (AT) and the other

side hung by the aitch bone for the pelvic suspension (PS) technique. All sides were

measured for core body temperature and muscle pH at 1 and 24 hours post-mortem

in the Longissimus dorsi between the 5th and 6th rib. BCS was measured ante-mortem

and confirmed with carcass measurements post-mortem. The M.gluteus medius

muscles (GM) (rumps) were boned out from each carcass side once carcass

temperature was less than 7° C. Samples were then vacuum packaged, frozen and

stored at -21º C for no more than 12 weeks, until sensory evaluations were carried

out. Kidneys with fat were excised for later KFI calculations according to the method

of Riney (1955) to assist confirmation of BCS.

7.3.1.2 Results

The data are arranged to compare sensory evaluation of venison from bucks and does

with a mean pHu of 5.50 (sem 0.02) (Table 7.1 and 7.2), differences in BCS (Table

7.4) and method of post-slaughter hanging in the chiller (Table 7.5). In the

comparison for sex effects (Table 7.1), venison from 36-month-old does scored

significantly higher for flavour strength (F1,336 =5.19, p<0.05), for tenderness

Chapter Seven

202

(F1,336=13.96, p<0.001) and for darker colour (F1,336= 30.027, p<0.001) compared

with the 18-24 month-old bucks. Panellists from age group 2 (35-44 years) detected a

difference in the flavour strength (Table 7.2) of samples according to the sex of the

deer. This age group determined that does had a stronger flavour (mean 8.57, sem

0.32) (p<0.01). The group with game meat eating experience detected a difference in

flavour strength between the sexes of animals (Table 7.3), with does determined to

be stronger in flavour than bucks (mean 8.73 sem 0.17) (p<0.001).

Table 7.1 : Mean (+/- sem) sensory evaluation scores for venison from fallow bucks (n=10)

and does (n = 10). All panellists (n=42).

Sex Colour Aroma Aroma

Strength

Flavour Flavour

Strength

Game

Flavour

Tenderness Juiciness Overall

Liking

Buck 7.74a

(0.18)

8.48a

(0.15)

7.73a

(0.17)

9.74a

(0.17)

8.12a

(0.17)

6.56a

(0.20)

8.71a

(0.22)

8.07a

(0.21)

9.97a

(0.20)

Doe 9.08b

(0.17)

8.71a

(0.16)

7.53a

(0.18)

9.92a

(0.18)

8.65b

(0.15)

6.90a

(0.20)

9.76b

(0.17)

7.96a

(0.21)

10.15a

(0.14)


Numbers in columns with the same letter are not significantly different.

Table 7.2 : Mean (+/- sem) sensory evaluation scores for venison from fallow bucks (n=10)

and does (n = 10), effect of panellist age (group 1 n=14, group 2 n=13, group 3 n=15) on

determination of flavour strength.

Sex Group

One

Group

Two

Group

Three

Buck 8.82a

(0.27)

7.35a

(0.33)

8.13a

(0.26)

Doe 8.53a

(0.28)

8.57b

(0.32)

8.77a

(0.22)



Chapter Seven

203

Table 7.3 : Mean (+/- sem) sensory evaluation scores for venison from fallow bucks

(n=10) and does (n = 10), effect of game eating experience (game eaters n=27, non-game

eaters n=15) on determination of flavour strength.

Sex Game

eaters

Non

game

eaters

Buck 7.96a

(0.19)

8.68a

(0.37)

Doe 8.73b

(0.17)

8.39a

(0.32)



Table 7.4 : Mean (+/- sem) sensory evaluation scores for venison from fallow bucks and

does with BCS of either 2 (n = 8) or 3 (n = 12). All panellists (n=42).

BCS Colour Aroma Aroma

Strength

Flavour Flavour

Strength

Game

Flavour

Tender

-ness

Juiciness Overall

Liking

2 8.41a

(0.19)

8.61a

(0.15)

7.60a

(0.17)

9.78a

(0.18)

8.49a

(0.17)

6.80a

(0.21)

9.22a

(0.20)

7.92a

(0.20)

10.06a

(0.20)

3 8.41a

(0.18)

8.58a

(0.16)

7.66a

(0.17)

9.87a

(0.18)

8.28a

(0.16)

6.66a

(0.19)

9.24a

(0.21)

8.11a

(0.22)

10.24a

(0.19)



For animals with BCS 2 and 3 there were significant differences between sexes in

colour (F1,128 = 61.44, p<0.001 and F1,128 = 6.58, p<0.01 respectively) with the

venison from does being rated as darker by consumers (n=42) (Figure 7.1).

Chapter Seven

204

Figure 7.1 : Sensory panel scores of meat colour for venison from fallow bucks and

does with BCS of 2 and 3.

There was also a significant interaction between sex of the animal for rating of

colour (F1, 336 = 6.01, p<0.01), regardless of BCS, with does being rated as darker

than bucks.

When the data were analysed for differences in consumer (n=42) evaluation of

venison from carcasses hung by either pelvic suspension or Achilles tendon (Table

6.3), the pelvic suspension method scored significantly higher (more desirable) for

tenderness (i.e. more tender) (F1,336=8.46, p<0.001) and juiciness (F1,336=6.53,

p<0.01), and were significantly lighter in colour (p<0.01). There were no significant

differences between factors for other sensory parameters measured.

0

1

2

3

4

5

6

7

8

9

10

11

BCS 2 BCS 3

C

o

l

o

u

r

Doe

Buck

Chapter Seven

205

Table 7.5 : Mean (+/- sem) sensory evaluation scores for venison from fallow bucks and

does hung by either the Achilles tendon or by pelvic suspension (n=20 of each), All

panellists (n=42).

Suspension

Method

Colour Aroma Aroma

Strength

Flavour Flavour

Strength

Game

Flavour

Tender-

ness

Juici-

ness

Overall

Liking

Achilles

Tendon

8.74a

(0.18)

8.39a

(0.16)

7.80a

(0.17)

9.74a

(0.16)

8.52a

(0.16)

6.71a

(0.20)

8.82a

(0.21)

7.64a

(0.21)

9.92a

(0.18)

Pelvic

suspension

8.09b

(0.19)

8.80a

(0.15)

7.46a

(0.18)

9.91a

(0.19)

8.25a

(0.17)

6.75a

(0.21)

9.64b

(0.19)

8.39b

(0.21)

10.38a

(0.20)


Measurements in columns with the same letter are not significantly different.

There was a significant interaction between BCS and method of carcass hanging. If

BCS was 2, there was no difference between the sexes in rating of overall likeness.

However, if BCS was 3, then venison from carcasses hung by pelvic suspension was

rated more acceptable than venison from carcasses hung by the Achilles tendon (F1,

170 = 7.266, p<0.01) (figure 7.2).

Figure 7.2 : Sensory panel scores of overall liking of venison from fallow bucks and

does with BCS of 2 and 3 hung by the Achilles tendon or by pelvic suspension.

7.3.1.3 Discussion

0

1

2

3

4

5

6

7

8

9

10

11

BCS 2 BCS 3

L

i

k

i

n

g

Pelvic

Achilles

Chapter Seven

206

From this set of experiments there were a number of key findings. Meat from fallow

deer does was generally more tender than bucks, even at older ages, and had a high

overall liking rating by consumers even though the meat was significantly darker and

had a stronger flavour. This finding is similar to that found with lamb where older

animals have stronger flavour profiles (Pethick et al 2002; Pethick et al 2005b).

Other studies in lamb have also found that colour strength increases as a function of

age, with lambs having the lightest colour followed by hoggets. The darker colour

was linked to increasing myoglobin levels (Pethick et al 2002; Hopkins et al 2005).

The middle-aged group of panellists detected a stronger flavour in does, possibly due

to the animals being older, and this age group of panellists contained a higher

percentage of current venison consumers than the other two age groupings. The game

meat eating group also detected a stronger flavour in the does, a finding possibly

related to prior game meat eating experience. This general acceptance of venison

from older does is quite important as farmers can now consider early culling of does

that are not performing in the breeding herd without losing carcass value. This

practice will only be effective if wholesalers also accept the consumer ratings from

sensory tests, and do not superimpose on venison values held for other domestic

meats. Unlike some studies of mutton (Pethick et al 2002; Thompson et al 2005b)

venison from older does in this study was more tender than venison from younger

bucks, and this is likely to be a result of sex differences rather than age. Similar

studies on cattle have shown heifers to be significantly more tender than steers and

bulls (Florek and Litwinczuk 2002; Weglarz et al 2002; Lundesjö et al 2003), ewes

more tender than rams (Craigie et al 2012) and goats (Rodrigues et al 2011), which

support the findings for deer in this and previous studies (Sims et al 2004). Studies

on red deer venison have demonstrated that physiological changes in male deer

triggered by increasing testicular secretion of testosterone around the rutting season

(breeding season) had negative effects on venison tenderness (Stevenson et al 1992;

Wiklund et al 2010), while no effects of season on venison tenderness have been

demonstrated for female deer. In reindeer venison evaluated by a trained taste panel,

adult bulls and cows had a more coarse fibre structure, more fat flavour and was less

tender than venison from reindeer calves (Wiklund et al 2002). The overall liking for

venison from older females in this study is an important finding for deer farmers.

Results from consumer testing indicated that venison from older cull females is

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207

desirable, with a number of sensory attributes rated more highly than venison from

younger bucks.

The data indicate no overall difference in liking for BCS 2-3 animals, hung by the

Achilles tendon, whether bucks or does. This is also important given that most

fallow deer presented for slaughter fall into this BCS range.

The consumers clearly distinguished their overall liking for venison derived from

carcasses treated with pelvic suspension post-slaughter compared with Achilles

tendon suspension. This preference was demonstrated by the important quality

characteristics of tenderness and juiciness which both increased in venison as an

effect of this technique. The ability of consumers to detect higher levels of juiciness

in samples from animals that were hung by pelvic suspension techniques supports

findings from a study by Wiklund et al (2004) where water holding capacity was

increased in meat from both fallow deer venison and lamb when comparing carcasses

hung by the pelvic suspension technique rather than the Achilles tendon hanging

method. Water holding capacity is an important meat quality attribute, as loss of

water in the form of purge or drip affects the appearance of vacuum packaged meat

and is also related to juiciness of cooked meat for table purposes (Wiklund et al

2009). This finding is also consistent with the data in Chapter 6, and indicates that

the technique of pelvic suspension should be adopted by the deer industry to produce

venison for which consumers have an increased preference. Similar studies in lamb

have also found pelvic suspension to be beneficial in producing more tender meat, as

assessed by consumers. (Thompson et al 2005b). Park et al (2008) confirmed these

results with beef. There was a significant interaction between BCS and method of

hanging between the sexes in rating of overall liking, whereby consumers were

unable to differentiate between venison hanging techniques at BCS 2, but had a

definite preference for venison from carcasses hung by the pelvis at BCS 3. As

shown in Figure 6.2, when scores are as close as these, it may be of little

consequence in the market where consumers only have a single sample to „analyse‟

at a meal. This increased rating for venison of higher BCS is further investigated

later in this chapter.

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208

7.3.2: Fallow deer - impact of supplementary feeding

7.3.2.1 Introduction

Body condition score is a useful tool in assessment of animal well-being, and a

frequently used descriptor in the buying and selling of livestock for slaughter. The

BCS of an animal can be altered by the presence or absence of supplementary feeds,

and meat production systems for beef (Hunter et al 2001), lamb (Pethick et al 2005a)

and goat meat (Adam et al 2010; Madruga et al 2008) frequently utilise

supplementary feeding to increase feed conversion efficiency and to produce

carcasses that consistently meet market specifications. These specifications are often

established according to the amount of subcutaneous fat coverage on the live animal,

and scales of reference have been established that allow accurate prediction of

carcass characteristics from live animal BCS assessments in fallow deer (Flesch et al

2002) and red deer (Audige et al 1998; Tuckwell 2003b).

In the quest to meet market specifications for various deer species, it is important to

define the effects of supplementary feeding of fallow deer on venison flavour.

Cooking methods are usually implicated in changes to the odour and taste of meat

(Bejerholm and Aaslyng 2003). However, the feed consumed by other domesticated

meat production animals such as cattle (Resconi et al 2010) and sheep (Resconi et al

2009) immediately prior to slaughter has been shown to alter the flavour of the meat,

with Lawrie and Ledward (2006) indicating that the degree of fatness of the carcass

can also change perceptions of flavour, due to concentrations of fatty acids.

Studies comparing the effects of grain vs. pasture finishing have usually been

conducted in the major meat species, cattle and sheep. McCaughey & Cliplef (1996)

fed steers with grain over 33 or 75 days prior to slaughter and compared the meat

quality with meat from animals in a pasture control group. The study demonstrated

that while pasture finished steers had lower yields and darker meat, with the majority

of animals meeting market requirements, there were no effects on tenderness,

juiciness, flavour and overall acceptability, according to consumer testing. Similar

studies were conducted by Pethick et al (2005a) on lamb, resulting in

Chapter Seven

209

recommendations that the decision to grain finish should be based on production

costs due to the limited impact on eating quality.

The sensory quality of deer venison has not been studied extensively, but some

research has reported intermediate to high sensory scores for tenderness, juiciness

and variations in the amount of game or “wild” flavour for red deer (Cervus elaphus)

(Wiklund et al 2003b), reindeer and caribou (Rangifer tarandus tarandus) (Rincker

et al 2006; Wiklund et al 2003a), and more recently, from this study fallow deer

venison (Hutchison et al 2010). The characteristic sensory attributes for venison

identified in these studies include highly tender and juicy, with flavour profiles

ranging from mild to livery, all leading to good overall acceptance by consumer

panels. Rodbotten et al (2004) developed a sensory map of 15 species, both

domesticated and non-domesticated. The deer venison included in that study was

from wild reindeer (Rangifer tarandus tarandus), moose (Alces alces) and roe deer

(Capreolus capreolus), with moose achieving the highest overall acceptability rating

from consumers, particularly in terms of tendernesss, flavour and juiciness.

In the current study it was evident that slaughter-aged (12-24 months) fallow deer are

usually in the BCS range 2-3, though older animals can reach BCS 4-5 seasonally or

when fed concentrates. In beef animals flavour intensity becomes greater as carcass

maturity and marbling increases (Aberle et al 2001; MSA 2001). It is important to

know if increased carcass fatness associated with concentrate feeding of deer alters

venison characteristics to the extent that consumers can detect a difference in flavour

compared with deer fed on pasture only, and if so, whether the change in flavour is

appreciated or not. This trial investigated the influence of supplementary feeding on

the eating quality characteristics of venison from fallow deer.


Non-pregnant, fallow does (n=24) approximately thirty six months old at the

commencement of the trial and with a history of one previous lactation, an average

live weight of 43 kg and BCS 2 (Flesch et al 2002), were slaughtered as part of a

supplementary feed trial (Chapter 5). The animals were quarter-bred hybrids of the

European type of fallow deer (Dama dama) and the Mesopotamian type (D.d.

Chapter Seven

210

mesopotamica), with European fallow deer being the dominant influence. Prior to the

feeding trial, all the does were raised principally on kikuyu pasture oversown with

ryegrass and oats during winter. Twelve of these does were grazed on kikuyu pasture

oversown with ryegrass and oats in winter. The remaining animals were fed barley

(800 g/animal/day) and lucerne hay 500 g/animal/day) during the supplementary

feeding period. The animals were randomly allocated to one of two groups: group 1

animals were slaughtered after 135 days of feeding (n=12; 6 grazing and 6

barley/hay fed animals) and group 2 after 170 days of feeding (n=12; 6 grazing and 6

barley/hay fed animals). All animals were fasted for 16 h prior to slaughter and their

live weights recorded before they were slaughtered as described in Chapter 3.

Samples were analysed to ascertain the effects of feeding on meat quality. This trial

also provided BCS 4 animals for establishing relationships between BCS and eating

quality..

7.3.2.3 Results

The data are arranged to compare sensory evaluation of venison from fallow deer

does of BCS 2, 3 and 4, raised on pasture only or supplementary-fed with grain and

lucerne hay and with an overall mean pHu of 5.52 (sem 0.01). There was no

interaction between BCS and feed for all sensory parameters measured, except for

flavour strength. Therefore, data were averaged over BCS for analysis of differences

between feed and averaged over feed for analysis of difference between BCS for all

sensory parameters measured except for flavour strength (Table 6.6). The only

difference in sensory attributes detected by panellists was a difference in flavour

strength between animals fed grain (mean score 8.52, sem 1.84) compared with

animals fed only pasture (mean score 8.08, sem 2.13) prior to slaughter, with venison

from grain-fed animals deemed to have a stronger flavour (p<0.05) (Table 7.7).

Analysis of variance for averaged data shows no significant differences between

BCS and feed for all sensory parameters analysed. However, there was a significant

interaction between BCS and feed for flavour strength (F1, 199 = 4.69, p<0.05). When

deer BCS was 3, consumers scored barley-fed (mean score 8.60, sem 0.33) animals

significantly higher than pasture (mean score 7.53, sem 0.37) fed animals (F1,79 =

Chapter Seven

211

4.76, p<0.05) but when the deer BCS was 4 there was no significant difference

between the feeding types for flavour strength (Figure 7.3).

Male panellists (n=21) detected a difference in flavour strength according to the

number of days the does were fed. The male panellists noted a stronger flavour when

animals were fed for 170 days when compared with animals fed for 135 days (Table

7.8) (mean 8.54 sem 0.26) (p<0.05). Female panellists did not detect this difference

in flavour strength.

Table 7.6 : Mean (+/- sem) sensory evaluation scores for venison from fallow does fed

on either pasture or grain prior to slaughter (n=12 per group). All panellists (n=42).

Feed

Treatment

Colour Aroma Aroma

Strength

Flav-

our

Flavour

Strength

Game

Flavour

Tender

-ness

Juici-

ness

Overall

Liking

Pasture 8.56a

(2.35)

8.34a

(2.41)

7.88a

(2.51)

9.49a

(2.18)

8.08a

(2.13)

6.99a

(2.81)

9.74a

(2.39)

8.34a

(2.81)

10.13a

(2.38)

Grain 8.21a

(2.48)

8.14a

(2.32)

8.03a

(2.63)

9.97a

(1.95)

8.52b

(1.84)

7.29a

(2.67)

10.03a

(2.16)

8.39a

(2.72)

10.55a

(1.90)


Measurements with the same letter in columns are not significantly different.

Table 7.7 : Mean (+/- sem) sensory evaluation scores for venison from fallow deer does

with BCS ranging from 2 to 4. All panellists (n=42).


Strength

Flav-

our

Flavour

Strength

Game

Flavo

ur

Tender-

ness

Juiciness Overall

Liking

2 (n=7) 8.49a

(2.52)

8.35a

(2.52)

7.82a

(2.35)

9.45a

(2.19)

7.97a

(1.79)

6.85a

(2.77)

10.03a

(2.27)

8.15a

(2.97)

10.08a

(2.51)

3 (n=7) 8.19a

(2.43)

8.17a

(2.41)

7.92a

(2.64)

9.77a

(2.02)

8.07a

(2.25)

6.97a

(2.77)

9.55a

(2.42)

8.11a

(2.68)

10.33a

(2.02)

4 (n=10) 8.60a

(2.32)

8.31a

(2.28)

8.02a

(2.59)

9.72a

(2.14)

8.59a

(1.87)

7.41a

(2.72)

10.08a

(2.18)

8.71a

(2.74)

10.38a

(2.24)


Measurements with the same letter in columns are not significantly different.

Chapter Seven

212

For BCS 3 the flavour strength for pasture-fed animals was significantly lower

(score=7.53 sem 0.37) than for animals fed barley (score= 8.60 sem 0.33). When

BCS was 4 there was no significant difference between pasture-fed and barley-fed

animals (Figure 7.3).

Figure 7.3 : Sensory panel scores for flavour strength of venison from fallow does with

body condition scores of 3 and 4, fed either pasture or grain prior to slaughter.

Table 7.8 : Mean (+/- sem) sensory evaluation scores for venison from fallow deer does

(n=24) fed for either 135 or 170 days on grain, effect of panellist gender on

determination of flavour strength.

Days of feeding Male Female

135 7.75a

(0.29)

8.33a

(0.37)

170 8.54b

(0.26)

7.96a

(0.33)



7.3.2.4 Discussion

0

1

2

3

4

5

6

7

8

9

10

11

BCS 3 BCS 4

F

l

a

v

o

u

r

S

t

r

e

n

g

t

h

Grain

Pasture

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213

Sensory evaluation is designed to measure the eating experience of the consumer.

Consumer preference is based on evaluation of predictive measures of meat quality

by the end user, and in this study differences between BCS, time on feed and feed

type were evaluated.

In beef animals, it has been reported that flavour intensity becomes greater as carcass

maturity and marbling increases (Aberle et al 2001; MSA 2010). For fallow deer in

this study, body condition score was increased by grain feeding young fallow deer to

achieve BCS 4, which was difficult to achieve by pasture feeding alone. Taste panels

found a significantly stronger flavour in the venison from animals fed grain prior to

slaughter, particularly in animals that remained at BCS 3. The flavour modification is

possibly due to changes in the fatty acid profile of venison from the grain-fed group

as shown in reindeer and red deer (Sampels et al 2004). Male panellists were

particularly able to detect a difference according to the number of days the animals

were fed concentrate feed, with longer feeding periods resulting in stronger flavours.

This result did not, however, affect overall liking or preference. Issanchou (1996)

stated that males rate flavour as more important than do females and this may explain

their perception and reporting of differences in flavour. These data are supported by

a number of other studies which also reported changes in flavour profiles in beef

(French et al 2001), lamb (Pethick et al 2002; Pethick et al 2005a), red deer (Wiklund

et al 2003b) and reindeer fed concentrate feed or grain immediately prior to slaughter

(Wiklund et al 2003a). However, the stronger flavour in venison from grain-fed

animals was not detected in animals of BCS 4 in this study, possibly as a result of the

higher intramuscular fat content altering the flavour strength of the muscle. Fat

content has been correlated with flavour in a study on red deer venison (Wilkund et

al 2008) and is known to influence the flavour profile of lamb (Pethick et al 2005a)

and kudu (Hoffman et al 2009). Panellists were unable to detect the increased

tenderness and fat content of the meat from BCS 4 animals that was determined by

instrumental measures (Chapter 4). As there were no significant differences in other

quality parameters between BCS 2, 3 and 4 animals, or between animals fed grain or

pasture, there would appear to be no justification for fallow deer farmers to finish

animals on grain prior to slaughter to achieve higher BCS. This is corroborated in a

Chapter Seven

214

study on beef heifers by Hessle et al (2007), where it was determined that

satisfactory carcasses may be achieved on pasture finishing.

The meat from all animals included in this supplementary feed study has also been

evaluated for colour stability during display and after chilled storage up to six weeks

in vacuum bags (Wiklund et al 2005). It was concluded that venison from the fallow

deer finished on pasture maintained the desired red meat colour for longer compared

with venison from the grain-fed deer (Wiklund et al 2005), which is another good

reason, from the perspective of consumer preference, for pasture based management

systems.

Feeding red deer and reindeer commercial feed mixtures (grain-based pellets) for 8-

10 weeks prior to slaughter has been demonstrated to significantly change the flavour

of venison compared with control groups of animals grazing natural pasture before

slaughter (Wiklund et al 2001a; 2003a). A study by Wiklund et al (2000) found no

significant differences in sensory attributes for female reindeer calves fed

commercial pellets and silage over the natural diet of lichens. In a separate study on

reindeer bulls Wiklund et al (2003a), the deer fed commercial feed scored higher for

liver and sweet flavour and lower for off flavour than reindeer reared on natural

grazing land and not fed concentrate feeds. A similar study was conducted by

Wiklund et al (2003b) on red deer stags reared on pasture or fed a commercial feed

mixture prior to slaughter. Trained panellists detected a difference in grassy flavour

in the two groups with the pasture fed group having more grassy flavour than the

group fed on the commercial concentrate. Kerth et al (2007) finished Angus-cross

steers (English x Continental) on rye grass forage or high concentrate diet and

presented the samples to a trained panel. Tenderness and flavour were not affected

by finishing regime, however meat from cattle finished on grain had a higher

consumer acceptability score. Realini et al (2009) found that European consumers

preferred beef that contained at least a portion of pasture in the finishing diet. Font i

Furnols et al (2009) determined that consumers preferred lambs fed on concentrate

feeds or a mixture of pasture and concentrate to those raised on pasture alone. This

was confirmed by Resconi et al (2009) where consumers indicated higher tenderness

scores and less off flavours and odours in lambs with concentrate included in their

diets.

Chapter Seven

215

In the previous section it was shown that flavour increased with increasing animal

age, and these data show that flavour can be increased by grain feeding animals of

the same age, compared with pasture-fed animals. This knowledge may be of some

importance to deer farmers producing for particular market preferences.

In this study the most important finding was that consumer preference was not

affected by finishing deer on concentrate feed or pasture prior to slaughter, or by

BCS. Optimal tenderness (shear force) was achieved in BCS 4 (Chapter 4), though

panellists rated all samples to be at the high end of the tenderness scale. This finding

was also reported for reindeer meat (Wiklund and Johansson 2011). This study

confirmed that fallow deer does of BCS 2-4 can be slaughtered year round with no

impact on the consumer acceptability of venison.

7.3.3 Red deer (pasture-fed)

7.3.3.1 Introduction

As mentioned previously, product consistency is vitally important for growth of the

domestic and export markets for Australian farmed venison. In Australia and

elsewhere, red deer are being farmed in increasing numbers for venison production,

and development of finesse in post-slaughter carcass treatment is likely to provide

significant return on investment because the anticipated improvements to product

quality will add significant value to the product. Venison from fallow deer and red

deer carcasses hung by pelvic suspension has been shown (Sims et al 2004 and

Chapter 5 of this study) to be consistently more tender than venison from carcasses

hung by the Achilles tendon, and this improvement to product quality has been

demonstrated across different sex and age classes of deer. The technique of pelvic

suspension is now used commercially for carcasses from domesticated species such

as beef and lamb, especially within quality control systems that guarantee a tender

product. The effect of pelvic suspension as an alternative carcass suspension

technique on meat quality has not been reported for red deer prior to this study, and

results in Chapter 5 demonstrated that meat tenderness increased for both raw and

cooked venison by using this technique, as measured in the laboratory by using a

Chapter Seven

216

Warner-Bratzler shear attachment on a texture analyser. This section now

investigates whether sensory evaluation panels can detect differences in venison

quality from red deer carcasses treated differently post-slaughter.

As previously described the level of fatness in a carcass can be detected by using

BCS as an indicator. At any given time there can be variation within and between

farms in the BCS of animals due to differences in age, sex, management practices,

disease status and climatic conditions, and venison quality will vary in response to

pressures exerted by these variations. Quite often, the only guide to whether an

animal is suitable for slaughter is its live weight and general body condition, and for

this reason it is important to know whether BCS per se is related to consumer

preference in the case of red deer venison. This section also explores consumer

perception of differences in BCS for red deer stags.


Pelvic suspension

Venison from rising 2 year old red deer stags (n=14) was used for this work.

Carcasses were split along the mid-ventral axis, and each carcass side was randomly

allotted to either Achilles tendon suspension (normal hanging technique) or to pelvic

suspension. GM muscles were excised and used for this experiment. Using this

experimental design, each animal was exposed to both treatments, and consumers

could evaluate venison from the same animal by tasting venison from each of the

treatments randomly.

Effect of BCS

Venison from red deer stags (n=26) killed commercially and with BCS ranging

between 2 and 4 was collected for this study (see Chapter 4). The sensory evaluation

techniques and tasting panel are as described for fallow deer experiments. The same

group of panellists (n=42) used in 7.3.1 and 7.3.2 were also utilised for this

experiment.

Chapter Seven

217

7.3.3.3 Results

The data are arranged to compare sensory evaluation of venison from red deer

carcasses BCS 2, 3 and 4 with a mean pHu of 5.54 (sem 0.02) hung by PS or AT.

Carcasses hung by pelvic suspension were preferred by panellists (n=42) for

tenderness (F1, 166 = 23.39, p<0.001), juiciness (F1, 166 = 10.46, p<0.001) and overall

liking (F1, 166 = 7.382, p<0.01) (Table 7.9). There were no significant differences

between AT and PS carcasses for other sensory parameters measured. The combined

effects of AT, PS and BCS on red deer venison tenderness, juiciness and overall

liking as judged by the sensory panels are shown in Figure 7.4.

Table 7.9 : Mean (+/- SEM) sensory evaluation scores for venison from red stags hung

by either the Achilles tendon or by pelvic suspension (n=14 of each). All panellists

(n=42).

Suspension

Method

Colour Aroma Aroma

Strength

Flavour Flavour

Strength

Game

Flavour

Tender-

ness

Juiciness Overall

Liking

Achilles 8.37 a

(0.27)

8.98 a

(0.24)

7.52 a

(0.27)

9.97 a

(0.25)

8.01 a

(0.24)

6.58 a

(0.31)

8.87 a

(0.33)

8.90 a

(0.29)

10.37 a

(0.28)

Pelvic 7.93 a

(0.29)

8.90 a

(0.24

7.46 a

(0.28)

10.36 a

(0.25)

8.22 a

(0.24)

6.57 a

(0.30)

10.85 b

(0.24)

10.22 b

(0.29)

11.38 b

(0.24)



Chapter Seven

218

Figure 7.4 : Mean (+/- SEM) sensory panel scores for tenderness, juiciness and overall

liking for venison from red stags with BCS between 2 and 3 hung post-mortem by the

Achilles tendon or by pelvic suspension.

There were significant differences in consumer perception between animals of

different BCS when judging tenderness (F2, 123 = 3.06, p<0.05) (table 6.10). Ryan‟s Q

test detected significant differences when venison from BSC 2 and BSC 4 animals

were compared, with panellists preferring venison from BCS 4 animals as it was

more tender (Figure 7.5). As BCS increased, consumer preference increased.

However, there were no significant differences in preference between BCS 2 and

BCS 3, and between BSC 3 and BCS 4. There were also no significant differences

between BCS for other sensory parameters measured. Male panellists (n=21)

detected a significant difference in colour (Table 7.11) between varying body

condition scores, indicating that darkness of the meat increased with BCS (p<0.05)

(mean: BCS 2, 7.21 sem 0.52; BCS 3, 8.60 sem 0.48; BCS 4, 9.00 sem 0.38).

However, female panellists did not detect differences in colour between BCS

(p>0.05).

0

1

2

3

4

5

6

7

8

9

10

11

Tenderness Juiciness Overall Liking

S

e

n

s

o

r

y

S

c

o

r

e

Achilles

Pelvic

Chapter Seven

219

Table 7.10 : Mean (+/- SEM) sensory evaluation scores for venison from red stags with

BCS of 2, 3 or 4 (n=12, 6 and 8 respectively). All panellists (n=42).


Strength

Flavour Flavour

Strength

Game

Flavour

Tenderness Juiciness Overall

Liking

2 8.25 a

(0.40)

8.85 a

(0.33)

7.80 a

(0.35)

9.74 a

(0.36)

7.92 a

(0.33)

6.56 a

(0.43)

8.85 a

(0.44)

8.87 a

(0.39)

10.18 a

(0.40)

3 9.00 a

(0.32)

9.13 a

(0.38)

7.58 a

(0.35)

10.37 a

(0.28)

8.30 a

(0.29)

6.76 a

(0.38)

9.60 ab

(0.40)

9.86 a

(0.36)

11.31 a

(0.30)

4 8.85 a

(0.31)

9.28 a

(0.41)

7.57 a

(0.36)

10.07 a

(0.36)

8.74 a

(0.29)

7.08 a

(0.42)

10.27 b

(0.38)

9.31 a

(0.41)

10.81 a

(0.40)



Figure 7.5 : Mean (+/- SEM) sensory panel scores for tenderness of venison from red

stags with BCS 2, 3 or 4. Higher scores indicate more tender meat.

0

1

2

3

4

5

6

7

8

9

10

11

BCS 2 BCS 3 BCS 4

T

e

n

d

e

r

n

e

s

s

Chapter Seven

220

Table 7.11 : Mean (+/- SEM) sensory evaluation scores for venison from red stags with

BCS of 2, 3 or 4 (n=12, 6 and 8 respectively), effect of panellist gender on determination

of colour.

BCS Male Female

2 7.21a

(0.52)

9.28a

(0.54)

3 8.60b

(0.48)

9.45a

(0.39)

4 9.00c

(0.38)

8.68a

(0.51)



Chapter Seven

221

7.3.3.4 Discussion

As for fallow deer, pelvic suspension of red deer carcasses produced venison rump

that was significantly more juicy and tender than the venison from carcasses hung by

the Achilles tendon. The overall liking for venison from carcasses hung by pelvic

suspension was significantly higher, and once again reinforced the data in Chapter 6

on the advantages to the deer industry of employing this technique. Tenderness is

consistently noted by consumers as the most important quality characteristics that

they look for in meat (Risvik, 1994), and the pelvic suspension technique has been

shown in these experiments to be consistently noted by panellists to produce venison

that is more tender and juicy. Venison is generally more tender than beef, and for

some deer species ageing of the meat is not necessary at all (Barnier et al 1999;

Wiklund et al 1997b). This phenomenon has been explained by high activity of

tenderising enzymes in venison (Barnier et al 1999; Farouk et al 2007) compared

with beef. Variation in meat pHu and glycogen content related to nutritional

status/body condition and pre-slaughter stress can give rise to considerable variation

in meat tenderness in species such as beef and lamb (Purchas et al 1999; Watanabe et

al 1996), and similar results have been found for red deer venison. Within the normal

pH range, values around 5.5 have been reported to yield more tender venison than

those in the 5.8-6.0 range (Stevenson-Barry et al 1999). This intermediate pH

venison was tougher than normal pH even after ageing, and more variable in

tenderness (i.e. of less consistent quality) than normal pH (deer) venison. In contrast,

reindeer venison has been found to be extremely tender regardless of meat pH

(Wiklund et al 1997a).

The pHu values measured in venison in the present study were in the range to

guarantee optimal tenderness which was supported by the consumer scores for

tenderness in fallow deer and red deer venison, all averaging values of 8 or above on

the scale from 0 (very tough) to 11 (very tender). This suggested that all venison

evaluated, regardless of species, sex, age, BSC or carcass hanging method, generally

was judged to be very tender, and data are in agreement with previously mentioned

comparisons of venison with beef.

Chapter Seven

222

There was a gradual increase in tenderness of venison as BCS increased from 2 to 4.

However, as seen in the previous section (7.3.1), this result can be obtained by

hanging carcasses differently after slaughter. As occurred in experiments with

fallow deer there were no differences in the range of quality parameters measured

across red deer carcasses ranging from BCS 2 to 4, except for a small increase in

tenderness, and again this is a good result for red deer farmers and wholesalers.

Animals ranging in BCS from 2 to 4 can be slaughtered without apparent effect on

consumer preference, which allows for flexibility in the supply chain. Until now

animals with low BCS (around BCS 2) have been considered to be largely unfit for

the venison market, yet the results obtained in the current study show that consumers

were reasonably happy with the meat. The current study does show a definite trend

by consumers to prefer venison from animals with a BCS of either 3 or 4, compared

with BCS 2, but this trend was not significant. The male panellists detected an

increased darkening of the meat as BCS increased, but this did not affect overall

liking or preference.

Chapter Seven

223

7.4: Conclusions

The hypothesis that changes in BCS would dramatically affect eating quality and

consumer preference has not been proven in these experiments for either species of

deer. The meat quality parameters measured (Chapter 4), however, showed

differences across the BCS range 2 to 4, in increases in tenderness, less redness and

higher levels of IMF, particularly in red deer and fallow deer does with BCS 4

compared with BCS 2 (Chapter 4). This difference is further confirmed by the slight

differentiation between BCS 2-4 by taste panellists, but with no negative

implications for overall liking. It is apparent from data for both red and fallow deer

that there was a trend for greater overall liking of venison from animals with BCS 3

and 4, compared with BCS 2, but this trend was not significantly different. It may be

necessary to slaughter larger numbers of animals to prove beyond doubt that this

trend is measurably significant.

Horsfield and Taylor (1976) concluded that the list of textural attributes can be

reduced to three basic descriptors without loss of information. They are

toughness/tenderness, succulence/juiciness and flavour. In the current study these

variables were shown to be relative to the overall liking of the product. An important

finding in this study was the enhancement of tenderness and juiciness in all carcasses

from red and fallow deer subjected to the pelvic suspension method of hanging

carcasses as they cooled down and entered rigor mortis. The sensory evaluation

scores for overall liking were consistently higher for venison from the carcasses

subjected to pelvic suspension, a further validation of the importance of tenderness

and juiciness as favoured quality attributes of meat by consumers.

The need to adopt the post-slaughter practice of pelvic suspension of deer carcasses

of all ages, sexes and body condition scores is unequivocal if enhanced tenderness of

venison is desirable. The sensory panels in this study validated the objective tests

that indicated increased tenderness and juiciness of venison from carcasses subjected

to pelvic suspension compared with venison from carcasses hung by the Achilles

tendon in all trials where the pelvic suspension technique was employed.

Chapter Seven

224

The technique of pelvic suspension can be easily installed as routine practice in

abattoirs once adopted, by altering the mechanics of how a carcass is added to and

removed from the meat rail into and out of the chiller. Carcasses can be re-hung by

the Achilles tendon for ease of transportation to the meat boning room of wholesale

and retail butchers so that retail cut shape of the meat is maintained, because the

process of tenderstetching carcasses is only effective while the carcass is cooling

down to a deep core temperature of 4-7 oC during the first 12-24 hours post-

slaughter. There are no mechanical reasons preventing the adoption of this valuable

technique to enhance meat quality, though uptake of this technology will require

cultural changes in the abattoir sector to alter traditional work practices. This could

prove difficult given the entrenched work practices in the abattoir sector (Mulley and

Falepau 1999)

Flavour is another key quality attribute evaluated by consumers and in this study

flavour was shown to increase as animals got older, and if they were fed grain prior

to slaughter. The trend for meat flavour to increase as animal age increases has been

shown in a number of studies and in a range of domestic species (Aberle et al 2001),

and is referred to anecdotally in reference to wild-shot deer (Whitehead 1993). The

detection by male panellists of stronger flavours in venison from deer fed grain prior

to slaughter was more surprising, and this finding could be used by the deer industry

to satisfy market preference for stronger flavours, or could be a warning to restrict

the feeding of grain prior to slaughter if stronger flavours are not desirable.

Interestingly, the stronger flavours in grain-fed deer were only detected in the lower

BCS range, and were not detected when BCS was 4. Perhaps higher carcass fat

levels in BCS 4 animals masked the flavour changes.

Venison from bucks vs. does for „overall liking‟ from the sensory testing indicated

consumer preference for venison from does. This is confirmed in a study on roe deer,

where meat from does was more tender than meat from bucks (Daszkiewicz et al

2012). This is useful information for the deer industry, especially with reference to

slaughter of fallow deer, because fallow deer bucks are very aggressive toward each

other during the breeding season and at this time of year carcasses can be bruised and

dehydrated. Venison quality can remain acceptably high by slaughtering cull female

stock during the breeding season.

Chapter Seven

225

Overall this study has shown that venison is a high quality product with meat quality

parameters similar to, or more desirable than, other domestic meats. Sensory


between the ages of 25 to 55, and differences in „overall liking‟ between red and

fallow deer venison were not detected in this study. The consumer scores for

tenderness in fallow deer and red deer venison in the present study all averaged

values of 8 or above on the scale from 0 (very tough) to 11 (very tender). This

supports the view that all venison evaluated regardless of species, sex age, BCS or

carcass hanging method, generally was judged to be very tender.

Chapter Eight

226

Chapter Eight

Conclusions and Recommendations for

Industry

Chapter 8 Conclusions and Recommendations for Industry ............................. 226

8.1 : Overall Conclusions ..................................................................................... 227

8.2 : Recommendations to Industry ..................................................................... 229

Chapter Eight

227

8.1: Overall Conclusions

This study investigated a range of factors that can impact on meat quality in farmed

deer, and provides, for the first time, an evaluation of these factors by consumers of

venison. The data provide consumer evidence that supports niche marketing

opportunities, which if exploited, can create new areas of business for the Australian

deer industry. In this study deer responded in a manner similar to other domesticated

ruminants in terms of manipulating the factors affecting meat quality, and for most

parameters tested there was close agreement between instrumental and sensory

analyses. Factors tested in this study and described elsewhere for the major meat

species, cattle and sheep (Hoffman and Wiklund 2006), include effect of animal age,

sex, planes of nutrition, pre-slaughter stress, post-slaughter suspension methods and

the effect of grain feeding on the meat quality and composition. Consumer

preference, and overall liking of venison from red and fallow deer, indicated sensory

differences in several key areas. There was a difference for some parameters tested

between the sex and age of consumers. Further, there was a clear preference for

venison from carcasses hung by pelvic suspension post-slaughter, for both species of

deer across all parameters. These findings in particular provide important new

guidance for the marketing of venison in Australia and elsewhere.

Links between live animal body condition, along with pre- and post-slaughter

management with subsequent meat quality and consumer acceptance have not been

investigated previously for venison. In this and previous studies (Mulley and Falepau

1999; Flesch et al 2002) involving the slaughter of large numbers of farmed fallow

deer, it was evident that most fallow deer less than 24 months old presented for

slaughter have BCS between 2 and 3, with a relatively smaller proportion with BCS

between 3 and 4. In red deer, the most common BCS in slaughter animals less than 2

years old also ranged between BCS 2 and 3, with older stags and cull hinds reaching

BCS 4 at certain times of the year (stags) and particularly in the case of hinds that did

not carry or rear a calf the previous year. Younger animals with higher BCS may be

commercially more valuable, particularly in terms of yields, although animals with

BCS ranging between 2 and 4 were shown in this study to produce venison that was

evaluated by consumers as high quality. Hence, the hypothesis that changes in BCS

Chapter Eight

228

would affect eating quality and consumer preference has not been clearly established

for either red or fallow deer. This important finding gives deer farmers greater

flexibility when establishing marketing options. Animals of BCS 2 had good

instrumental tenderness and good overall liking by consumers. Animals with BCS 3

and 4, along with venison from female animals, may be able to provide a premium

product with enhanced tenderness if desired by niche markets.

The most important finding in this study was the enhancement of tenderness and

juiciness in all carcasses from red and fallow deer subjected to the pelvic suspension

method of hanging compared to the Achilles tendon method. This enhancement of

quality assurance provides the deer industry with an opportunity to increase

tenderness and juiciness of BCS 2 and male animals to the levels achieved by does

and animals of higher BCS. As stated previously, the aim of this work was to find

ways to improve quality assurance of venison produced by the Australian deer

industry, and the data for use of pelvic suspension as the preferred method of post-

slaughter carcass management are unequivocal.

This study showed that fallow deer does between BCS 2 and 4 can be slaughtered

with no impact on consumer acceptability of venison. While female deer tended to

produce venison of higher quality in terms of consumer acceptance and instrumental

measures of tenderness, the Australian deer industry needs to retain as many

reproductive age females as possible to increase the size of the national herd.

Processing large numbers of female deer, apart from cull does or hinds, would be

counterproductive to industry growth. The females need to be retained for breeding,

not processed for venison (Shapiro 2010). Techniques such as pelvic suspension are

invaluable to the deer industry because similar meat quality characteristics can be

achieved in young slaughter-aged male deer, compared with females, by using this

technique. This outcome increases the opportunity to slaughter male deer year round,

while maintaining consumer acceptance, and preserving female deer for breeding

stock.

Another important finding of this study was that instrumental meat quality and

consumer preferences were not significantly enhanced by finishing animals on

concentrate feeds prior to slaughter. Although optimal instrumental tenderness was

Chapter Eight

229

achieved in animals of BCS 4, which was achieved through concentrate feeding,

consumers rated all samples to be at the high end of the tenderness scale. Venison

from pasture based systems also exhibited a longer chilled display life. Pasture based

management systems are more economical for deer producers, and venison from deer

finished on pasture pre-slaughter has been evaluated by consumers in this study as

being of equally high quality compared with venison from animals finished on grain.

Overall, this study has shown that venison is a high quality product. Sensory


between the ages of 25 to 55, and differences in „overall liking‟ between red and

fallow deer venison were not detected.

Consumer perception of venison is a critical issue for the Australian deer industry.

The scientific contribution of this study will assist the venison industry to improve

consistency and quality of their product.

8.2: Recommendations to Industry

As a result of this study a number of key recommendations for the Australian deer

industry have been formulated.

The initial aim of this study was to identify any links between live animal BCS and

instrumental and sensory quality of venison. These links have been made, further

enhancing the use of a common BCS language across all sectors of the deer industry.

Recommendation 1: All animals within the BCS range of 2-4 can be slaughtered to

produce venison that is highly acceptable to consumers. For premium ends of the

market, producers may choose to attain BCS 4 by grain finishing their animals, or

process does in order to achieve increased tenderness.

This study showed that feeding concentrates can improve BCS and HCW in a desired

time frame, and that production of animals in a range of body conditions, with or

Chapter Eight

230

without the use of concentrate feeds, can result in high quality product. The cost

benefit of feeding programs is one to be determined by the producer and processor.

Recommendation 2: Concentrate feeding can be used to produce a premium product

with enhanced tenderness, as a result of increased BCS and a stronger flavour profile.

Pasture feeding produces venison of consistently good quality with longer chilled

display life. The decision to feed concentrates or use a pasture based system is left to

the discretion of the producer and the processors with no real adverse effects on

venison quality.

Recommendation 3: In situations where longer display life is an important

marketing requirement, animals should be finished on high quality pasture prior to

slaughter.

Possibly the most important finding emanating from this work is the need to utilise

the technique of pelvic suspension for deer carcasses. This post-slaughter

management technique was shown to increase tenderness of venison, in all sex and

age groups of animals, significantly so with males of both species.

Recommendation 4: Pelvic suspension should be used for post-slaughter hanging of

deer carcasses until the carcass reaches pHu.

Does, regardless of age, produced venison of increased tenderness and acceptability

for consumers, compared with bucks. Pelvic suspension of carcasses from males

increased tenderness to levels similar to those measured in females. This is a vital

piece of information for an industry that needs to maintain breeding stocks of

females, while producing meat of consistently high quality.

Recommendation 5: Pelvic suspension hanging should be applied to carcasses from

all male deer slaughtered.

Opportunities now exist for the industry to bring about greater consistency of

product, as has occurred in other livestock industries such as beef and sheep. The

Chapter Eight

231

relationship of BCS, instrumental measurements of deer venison quality and sensory

evaluation by consumers has important implications for all sections of the value

chain, especially in smaller industries such as the deer industry where it is critical

that product potential is maximised. This study has produced new information that

can underpin venison as a quality assured product, and is industry ready for adoption.

References

232

References

AACMI. 1994. Deer marketing and production study. Rural Industries Research and Development Corporation, No 91/1, RIRDC, Canberra, ACT.

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Appendix

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Appendices

The author’s four children with two hand raised fallow deer haviers.

Appendix 1 ........................................................................................................... 276

Australian Body Condition Chart for Fallow Deer .............................................. 276

Appendix 2 ........................................................................................................... 277

Australian Body Condition Chart for Red Deer ................................................... 277

Appendix 3 ........................................................................................................... 279

Body Condition Score Chart for Red Deer .......................................................... 279

Appendix 4 ........................................................................................................... 280

Sensory Evaluation of Venison ............................................................................ 280

Appendix

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Appendix 1

Australian Body Condition Chart for Fallow Deer

Tuckwell et al 2000a

Appendix

277

Appendix 2

Australian Body Condition Chart for Red Deer

Appendix

278

Tuckwell et al 2000b

Appendix

279

Appendix 3

Body Condition Score Chart for Red Deer

Audige et al 1998

Appendix

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Appendix 4

Sensory Evaluation of Venison

Sensory Evaluation of Venison

Date: _____________ Time: ____________ Name: __________________________

Sample Code: __________________ Please rate the sample for the following characteristics by marking on the line scale where it best describes your impressions.

1. Please do not taste yet! Please look at the sample and rate its colour

COLOUR Extremely Pale Extremely Dark

________________________________________________

2. Please smell the sample and rate its aroma

AROMA Dislike Extremely Neither Like nor dislike Like Extremely

________________________________________________

AROMA STRENGTH None Extremely Strong

________________________________________________

3. Now taste the sample of venison and rate the following characteristics:

FLAVOUR Dislike Extremely Neither like nor dislike Like Extremely

________________________________________________

FLAVOUR STRENGTH None Extremely Strong

________________________________________________

GAME FLAVOUR None Extremely Strong

________________________________________________

TENDERNESS Extremely Tough Extremely Tender

________________________________________________

JUICINESS Extremely Dry Extremely Juicy

________________________________________________

OVERALL LIKING Dislike Extremely Neither like nor dislike Like Extremely

________________________________________________

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