Dan MorricalIowa State University

Extension Sheep Specialist

Carcass Component Growth

DGM:ISU

Lean tissueAdipose tissue Skeletal tissue

Components

DGM:ISU

AgeWeight

FatColor

FirmnessMuscle

Carcass value

DGM:ISU

Moderately leanHeavy muscled

Carcass value

DGM:ISU

Projected Target Market Weights

Fat Thickness (12-13th rib)

.15 .25 .35

Frame Size WETHERS

Small 92 116 140

Medium 97 126 154

Large 109 140 170 Tatum, 1992

Frame Size, Growth and Carcass Traits

DGM:ISU

Texas Rambouillet WethersSmall Medium Large

Carcass wt. 54 51 50

Backfat .18 .11 .07

Ribeye 2.02 2.05 1.98

Carcass Parameters, Constant weight 105 pounds

Small Medium Large

DOF 55 30 19

Slaughter weight 105 105 105

DP 51.6c 48.7d 47.9d

FT in 0.18 0.11 0.07

REA 2.2 2.05 1.98

% Choice 98.9 98.7 95.9

Nicholes

Carcass tissue weights of mature rams of two strains of Merinos of different mature size (Data from Butterfield et al., 1983a)

Weight (kg)

Whole Carcass Tissue Large n=3 Small n=3Sig. of

Diff.

Muscle 25.9 20.7 ***

Bone 6.4 4.9 **

Fat 26.7 18.8 **

Liveweight 116.5 90.9 ***

kgLiveweight 4 10 20 30 40 50 60 70 80 90 100=100

Carcass muscle 5 12 24 35 46 56 66 75 84 92 100=22.5Carcass bone 8 18 27 39 50 60 70 79 87 94 100=5.5Carcass fat 1 2 5 10 18 27 38 50 65 82 100=21.8

Percentage Maturity

The progress of carcass tissues of a Merino ram to maturity at 100 kg LW relative to the progress to maturity of shorn full LW

Carcass tissues as % of shorn full LW of mature rams of two strains of Merinoes of different mature size (Data from Butterfield et al., 1983

Percent of LW

Whole Carcass Tissue Large n=3 Small n=3Sig. of

Diff.

Muscle 22.3 22.8 NS

Bone 5.5 5.4 NS

Fat 23.0 20.7 *

LW 100.0 100.0

Fat partitions by sex

Fat partition % of total body fat Ewes as % of rams

Rams N=18 Ewes N=16

Subcutaneous* 30 33 1.1

Intermuscular*** 30 26 0.87

Total carcase 60 59 0.98

Kidney** 12 15 1.25

Omental 18 17 0.94

Mesenteric 7 7 1

Scrotal/Udder*** 3 2 0.67

Total non-carcase 40 41 1.02

Total Body 100 100

(Adapted from Thompson 1983)

Rams Ewes Ewes = 1

Rams =

27.1 23.9 1.13

4.8 4.1 1.16

13.5 18.1 0.75(Data from Fourie et all, 1970)

Muscle

Bone

Fat

% of LW Ratio

The carcass tissues as % of mature full LW of a combined group of Romney, Southdown and Romney Southdown crosses

Whole carcass tissue

Which group is better

DorsetDown

Hamp.Down

Ile deFrance

Southdown Suffolk Texel s.e. Mean

Age at slaughter (days) 218 236 253 234 249 247 6

Carcass wt (kg) 17 17.7 18.4 16.4 19.1 18.8 0.1

Daily carcass wt gain (g) 86 86 78 80 84 83 2

M. longissimus

Width A-mm 55.1 56.2 57 55.3 58 57.7 0.52

Depth B-mm 26.0a 25.5a 27.5b 25.8a 26.4a 27.4b 0.35

DorsetDown

Hamp.Down

Ile deFrance

Southdown Suffolk Texel s.e. Mean

Carcass conformation

(15 pt scale) 7.6bc 7.5bc 8.2c 8.3c 7.8c 7.9c 0.23

Tissue in carcass (g/kg)

lean 557a 562ab 571b 559ab 567ab 590c 3.2

separable fat 267cd 263bcd 255bc 273d 252b 240a 3.3

Daily tissue wt gain in carcass (g)

lean 47 45 43 43 46 47 1

separable fat 22 22 20 22 21 20 0.57

Ile DeFrance

Suff Coop DLS Rom Fin

Slaughter wt 95.5 92.4 95.5 93.3 93

Age (d.) 204 222 239 222 264

BF 0.15 0.18 0.16 0.12 0.20

REA 1.83 1.65 2.17 1.67 1.80

Fahmy etal 1992 J. Anim Sci 70:1365

Sire Breed Impact on Growth and Carcass

Carcass Traits by Sire Breed

Hamp Polypay

Gain 0.72 0.65

FE 6.60 6.70

Backfat 0.30 0.30

Bodywall 0.96 1.00

REA 2.43 2.29

YG 2.50 2.50

No impact on individual cuts

Meyer et al, 1993, SRJ 9:97

Effect of Sire Breed on carcass traits, adjusted for carcass weight

Dor Tex Mon Fin Rom

Slaughter wt 114 113 113 114 117

BF .25a .29b .24a .31b .29b

REA 2.35a 2.54b 2.41a 2.12c 2.24a

Freking and Leymaster. 2004. J. AnSci 82:3144

Evaluation of Texel, Columbia and Suffolk as Terminal Sires along with Finishing System

T S C BG FL

DP 51.1 52.0 51.0 51.0 51.7

BF 0.23 0.20 0.20 0.20 0.25

Bodywall .99a 1.07b 1.14c 1.00 1.12

REA 2.6 2.4 2.4 2.6 2.4

Morrical IASBR, 1994.

Restricted feeding on Growth and Carcass

Intake Level

100% 85% 70%

ADG 0.90 0.76 0.65

FE 3.3 3.4 3.4

% Water 49.6 51.2 51.5

% Protein 15.1 15.6 15.4

% Fat 31.1 29.0 28.2Murphy et al 1994 J. AnSci 72:3131

Impact of protein content and source on performance and carcass.(prolific crosses)

FM SBM CGM& BM Control

16% 16% 16% 13%

ADG .49a .41b .48a .40b

FE 4.99a 5.48b 5.11ab 5.76b

BF 0.15 0.17 0.16 0.18

REA 1.95 1.91 1.84 1.84

90 lb slaughter weightFahmy et all 1992 J. AniSci

Impact of Protein Source and Level on Suffolk Wether Growth and Performance

CP SBM SBM&F

13 16

ADG 0.98 1.00 0.98 0.97

FI 4.5 4.5 4.6 4.4

FE 4.6 4.6 4.7 4.6

BF 0.18 0.17 0.17 0.16

%lean 53.0 54.7 54.0 53.6

Ribeye Area 2.63 2.72 2.66 2.68

Neary et al, 1995

Frame Size and Feeding Method

Small Medium Large

Wheat Pasture gain 0.14 0.15 0.14

Feed lot gain 0.60 0.72 0.73

FE 7.2 6.6 5.6

Finishing System Impacts on CarcassC FC

Carcass Wt 63.1 57BF 0.35 0.3Bodywall 1.1 0.9

Age vs System. No effects on cuts.

Summary

Sex has an impact

Protein level

Older/backgrounding improves

cutability