I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits.

IOWA STATE UNIVERSITYDepartment of Animal Science

Terminal Traits


Heterosis Review

What is Heterosis - offspring performance difference over the average performance of an offspring’s parents

Why maximize heterosis? It is FREE producers are wasting money if you do not take advantage of it.

Performance of Sire = 2.00 ADG

of Dam= 1.80 ADG

Parental Average = 1.90

Offspring Average ADG = 2.10

Offspring – Parental Average = 2.10 – 1.90 = .20

Percent Heterosis = .20 /1.90 = 10.5%


Types of Heterosis

1. Individual Advantage of a crossbred offspring over purebred parents

2. Maternal Advantage of a crossbred mother over a purebred mother Primarily due to mothering ability

3. Paternal Advantage of a crossbred father over a purebred father Due to fathering ability? Not as important as maternal heterosis


Heterosis advantage for production traits (Ahlschwede et al., 1988)

ItemFirst Cross

purebred sow

Multiple cross crossbred

sow

Crossbred boar

ReproductionReproduction

Conception rate 0.0 8.0 10.0

Pigs born alive 0.5 8.0 0.0

Littersize at 21 days 9.0 23.0 0.0

Littersize weaned 10.0 24.0 0.0



ItemFirst Cross

purebred sowMultiple cross crossbred sow

Crossbred boar

ProductionProduction

21 – day litter weight 10.0 27.0 0.0

Days to 250 lbs. 7.5 7.0 0.0

Feed Efficiency 2.0 1.0 0.0



ItemFirst Cross

purebred sowMultiple cross crossbred sow

Crossbred boar

Carcass CompositionCarcass Composition

Length 0.3 0.5 0.0

Backfat -2.0 -2.0 0.0

Loin muscle area 1.0 2.0 0.0

Marbling 0.3 1.0 0.0


Crossbreeding Systems

Rotational crossbreeding systems Three-breed


Types of Crossbreeding Systems

Rototerminal


Crossbreeding Systems

Rotaterminal crossbreeding systems A good compromise between specific and rotational systems More heterosis realized than with rotational alone Still can save replacement breeding stock

Still must buy terminal sire Can select traits in individual breeds via the terminal sire

Can focus on strengths and weaknesses of certain breeds


Heterosis percentage in rotational crosses

Generation number

EquilibriumCrossbreeding System 1 2 3 4 5 6

2 breed rotation 100.0 50.0 75.0 62.5 68.9 67.2 66.7

3 breed rotation 100.0 100.0 75.0 87.5 87.5 84.4 85.7

4 breed rotation 100.0 100.0 100.0 87.5 93.8 93.8 93.3

5 breed rotation 100.0 100.0 100.0 100.0 93.8 96.9 96.8

6 breed rotation 100.0 100.0 100.0 100.0 100.0 96.9 98.4


Using Heterosis

Disadvantage Superior performance observed in crossbred individuals is not transmitted

upon mating Gene combinations are not transmitted to progeny

Only individual genes are transmitted to progeny Additive gene action = heritability, EPDs, EBVs

Gene combinations are rearranged or lost when crossbred animals are mated together

Random segregation of alleles during meiosis


Swine Production Goals

Primary goal = Maximize Profit

Genetics has a permanent effect on profit through influence or economically important production traits. Start with the best genetic merit nucleus

animals Improve their merit Use the most efficient Genetic System Provide an adequate environment for the

animals to express their genetic merit


Development of a Breeding Program

Identify production and carcass traits that influence profitability

Assess relative economic value of traits

Evaluate economic goals and production restrictions

Evaluate packer buying program used

Use records to evaluate current situation


Selection Indexes

Indexes are used for multiple trait selection

Indexes combine the traits that economically influence a selection decision

MLI = Maternal Line Index used for selection of sows and maternal line males

TSI = Terminal Sire Index


Terminal Sire Index (TSI)

Days to 250 Pounds (114 kg)

Backfat

Loin Muscle Area

Pounds of Lean in 185 pound (84 kg) carcass


Terminal Traits

Terminal traits have greatest economic impact when the commercial offspring are marketed

Traits related to Growth

Average daily gain (ADG) Average daily lean growth (ADLG) Days to market (Days) Days to some constant weight (Days to 250 lbs or 113 kg)


Terminal Traits


Traits related to Carcass Composition

Backfat (BF) Loin muscle area or loin muscle depth (LMA or LD) Carcass lean % Fat free lean (FFL)


Terminal Traits


Traits related to Efficiency

Feed intake (ADFI) Feed efficiency (F:G or G:F) Lean efficiency (F:LG or LG:F) Role that gain plays with feed efficiency


Terminal Traits


Traits related to Carcass Quality

pH Drip loss Color

Minolta – Objective color scoring

Scoring – Subjective color scoring Marbling or IMF


Terminal Traits


Traits related to Eating quality

Instron tenderness Cooking loss Consumer acceptance Sensory meat panel scores

Juiciness

Tenderness

Flavor

Off-flavor


Heritability Estimates

Trait Heritability Estimate Number born .10 21-d litter weight .15 Number weaned .05 Average feed intake .24 Average daily gain .30 Days to 250 lbs. .35 Feed efficiency .30 Backfat .40 Loin muscle area .45


Relative Economic Value of Swine Traits


NBS Breed Differences for ADG

bc

cdbc

ab

d

a

c cd

1.6

1.65

1.7

1.75

1.8

1.85

B CW D H L PC S Y


NBS Breed Differences for BF10

bccd

bbde

e

0

0.2

0.4

0.6

0.8

1

1.2

1.4

B CW D H L PC S Y

a


NBS Breed Differences for LMA

ee

bc bcde

cdb

4

4.5

5

5.5

6

6.5

B CW D H L PC S Y

a


NBS Breed Differences for pH

aa

b

db c c

5.3

5.4

5.5

5.6

5.7

5.8

5.9

B CW D H L PC S Y

e


NBS Breed Differences for Hunter L

cbcb

d

b

a

45

46

47

48

49

50

51

52

53

B CW D H L PC S Y

a

b


NBS Breed Differences for IMF

bcb

a

dc c

d

0

0.5

1

1.5

2

2.5

3

3.5

4

B CW D H L PC S Y

d


NBS Breed Differences for Instron

ccd

d

bb

a

5

5.25

5.5

5.75

6

6.25

6.5

B CW D H L PC S Y

bb


Sex Differences in NBS Progeny Test

Trait Barrow Gilt Interaction

ADG 1.81 1.67 Yes

BF10 1.20 0.98 Yes

LMA 5.34 6.00 Yes

pH 5.66 5.64 No

Hunter L 50.4 49.3 No

IMF 3.16 2.55 Yes

INST 5.63 5.94 No


Growth and Carcass Traits in the NGEP

Sire Line ADG (lb/d) LGOT BF10 (in.) LMABerkshire 1.85c .63c 1.25d

5.74c

Danbred HD 1.83c .72a 0.98a

6.75a

Duroc 1.95a .70ab 1.13c

6.14b

Hampshire 1.87bc .71a 1.01a

6.58a

NGT LW 1.87bc .65c 1.17cd

5.62c

NE SPF Dur. 1.97a .73a 1.11bc

6.35ab

Newsham 1.90ab .73a 0.98a

6.45a

Spotted 1.84c .63c 1.24d

5.83c

Yorkshire 1.84c .68b 1.05ab

6.17b


Meat Quality Traits in the NGEP

Sire Line Min. pH Drip (%) IMF(%)Berkshire 21.8a 5.91a 2.43a 2.43bc

Danbred HD 22.6b 5.75cd 3.34cd 2.61b

Duroc 22.3ab 5.85ab 2.75ab 3.19a

Hampshire 23.3c 5.70d 3.56d 2.61b

NGT LW 21.4a 5.84ab 2.92bc 2.25c

NE SPF Dur. 22.6b 5.88ab 2.81ab 3.30a

Newsham 22.2ab 5.82bc 2.99bc 2.27c

Spotted 22.9bc 5.83bc 2.88b 2.65b

Yorkshire 22.1a 5.84ab 2.85b 2.42c


Eating Quality Traits in the NGEP

Sire Line C. L. (%) Instr. (kg) Tend. (1-5) Moist.(%) Berkshire 22.5a 5.33a 3.50a 66.0a

Danbred HD 24.3b 5.85c 3.45ab 65.3ab

Duroc 23.1ab 5.64b 3.38ab 65.0b

Hampshire 26.0d 5.82c 3.36ab 65.0b

NGT LW 22.9ab 5.75bc 3.16c 65.5ab

NE SPF Dur. 22.5a 5.52ab 3.36ab 65.3ab

Newsham 24.2bc 5.87c 3.25bc 65.1b

Spotted 23.4ab 5.68b 3.16c 65.5ab

Yorkshire 23.5bc 5.87c 3.26bc 65.3ab


NGEP Terminal Line Results -- Ranked on % Lean

%Lean Min pH IMF Inst.Danbred HD 52.0 23.0 5.75 2.33 5.81Newsham 51.3 22.7 5.82 2.25 6.12Hampshire 51.2 25.3 5.70 2.57 5.86Yorkshire 49.9 23.0 5.84 2.33 6.13NE SPF Dur. 49.8 23.1 5.88 2.71 5.78Duroc 49.0 23.2 5.85 3.03 5.65NGT LW 47.7 23.4 5.84 2.15 6.09Spotted 47.4 23.3 5.83 2.35 5.92Berkshire 47.0 22.6 5.91 2.41 5.74


Heritabilities and Genetic Correlations on the NGEP

BF10 LMA MIN pH IMF C.L. INST BF10 .46LMA -.61 .48Minolta .08 .02 .25Ult. PH .03 -.11 -.49 .38IMF .30 -.25 .11 0.0 .47Cook. Loss .01 .01 .26 -.45 -.02 .08Instron -.17 .15 .18 -.42 -.17 .58 .20

Heritabilities on diagonal and geneticcorrelations below diagonal


Heritabilities and Genetic Correlations for Selected Traits in the NGEP

ADFI DAYS BF10 LMA pH IMF MIN WHC

ADFI .50

DAYS -.50 .57

BF10 .13 -.05 .46

LMA -.13 .05 -.61 .48

PH -.05 .10 .03 -.11 .38

IMF .01 -.09 .30 -.25 .00 .47

MIN .06 -.11 .08 .02 -.49 .11 .25

WHC .06 -.06 -.05 .13 -.92 -.02 .52 .19

Heritabilities on diagonal and genetic correlations below diagonal


Heritabilities and Genetic Correlations for Production Traits Estimated from NGEP Data

Ave. Daily Feed Intake .50

Ave. Daily Gain-SEW .19 .43

Days/250 -.50 -.60 .57

Ave. Daily Gain .58 .31 -.90 .50

Lean Gain Per Day .29 .33 -.62 .61 .48

Soundness .10 .18 -.14 .09 .07 .19

ADGADG

ADFIADFI SEWSEW D250D250 ADGADG LNGNLNGN SOUN.SOUN.

Heritabilities on diagonal and genetic correlations below diagonal.Heritabilities on diagonal and genetic correlations below diagonal.


“Quality” Indicators

Color

Marbling

Firmness

Water holding capacity

pH

Tenderness

Taste


Measurement of Color

Minolta Chromameter Minolta (range of 17-33) Hunter L (range of 40-60)

New NPPC Color Standards (1-6)

1 2 3

4 5 6


Color Scores

1 2 3

4 5 6


Water Holding Capacity

Kauffman filter paper method

Measures amount of moisture on the cut loin surface

Low numbers indicate less moisture loss

Visual Firmness/Wetness Scores (Very Firm, Firm, Soft)

Drip loss -- measures purge


Ultimate pH

Measured 24 hours after

slaughter

Insert pH probe into the muscle

Higher pH = darker color, low drip loss, more firmness, increased tenderness

Predictor of water holding capacity

45 minute pH is indication of PSE


Intramuscular Fat (IMF)

Marbling or lipid content

Laboratory analysis

Minimum amount is necessary for desirable eating quality (2.0 - 2.5%)

New NPPC Marbling Standards (1-10)

Standards correspond to intramuscular lipid content


Marbling Scores

1 2 3 4

5 6 10


Tenderness

Instron tenderness using

star probe

Measures pressure to compress cooked sample

Less pressure = more tender


Sensory Panel Scores

Trained sensory panel

Evaluation of palatability Tenderness Juiciness Chewiness Flavor


Objectives of the Study:

An evaluation of pH and hydrogen ion concentration (H+) was conducted to determine if the mathematical conversion of H+ to pH could affect 1. prediction of genetic merit of animals when pH or H+ is used as an indicator in the assessment of pork quality.


Introduction

Use of pH is becoming widely accepted as an indicator of pork quality.

Meat scientists and geneticists are focusing on pork quality traits and their indicators in an attempt to improve the quality of commercially produced pork.

Pork harvesting and processing industries are concerned with identifying environmental factors that can improve pork quality and its indicator traits so that more of their products can be sold as premiums products at the market place.


Definition of pH

pH = - log base 10 * Hydrogen Ion Concentration (Zubay, 1988).

This transformation was made not to normalize the distribution, but to reduce the size of the decimal evaluated.

The transformation can present a potential problem.


Table 1. An example of two sires with three progeny and each having identical pH averages, but differing hydrogen ion concentration.1

Progeny phenotypic pH

valuesAverage pH

ValueMean Hydrogen Ion

Concentration

-log 10 (mean H+), (pH

units) Sire A 5.6, 6.2, 6.2 6.00 1.2579E-06 5.90

Sire B 5.7, 6.0, 6.3 6.00 1.1655E-06 5.93

1Mean hydrogen ion concentration values have been converted to pH values (taking the negative log base 10 of the original value) in order to compare them on the same scale.


Procedures

Data from the National Barrow Show™ (George A. Hormel Company, Austin, MN) Purebred Progeny Test was utilized

Complete three-generation pedigrees, fixed and random classifications used for analyses, and pertinent muscle quality data were obtained from the

National Pork Board (Des Moines, IA)

Existing carcass longissimus pH data was converted to its original hydrogen ion concentration

» H+ = 10-pH


Procedures cont’

Hydrogen ion concentration and pH genetic predictions and heritabilities were estimated using the ASREML software (Gilmour et al., 2001)

A sire model with the full relationship matrix was incorporated


Heritability estimates (± SE), genetic gain estimations, and breeding value correlations of pork carcass longissimus pH and hydrogen ion concentrations from the National Barrow Show™ Progeny Test.

Trait H2 ± SE

Overall mean1Correlation of BLUP

breeding values2

pH 0.52 ± 0.074 5.681(20.84 * 10-7)

-0.92 (-0.85)

Hydrogen ion concentration

0.62 ± 0.078 23.36 * 10-7

(5.631)

1pH and Hydrogen ion concentration means have been converted to their corresponding values and are presented in parenthesis.

2Values are Pearson correlation coefficient and (Spearman rank correlation coefficient).


Residual distribution of pork carcass longissimus pH and hydrogen measures from the National Barrow Show ™Progeny Test

0

200

400

600

800

1000

1200

1400

Nu

mb

er

of

Ob

se

rva

tio

ns

<=5.0

9

5.2

0-5

.29

5.4

0-5

.49

5.6

-5.6

9

5.8

0-5

.89

6.0

0-6

.09

6.2

0-6

.29

6.4

0-6

.49

6.6

0-6

.69

6.8

0-6

.89

7.0

0-7

.09

pH Residual Distribution

0200

400600800

100012001400

Nu

mb

er

of

Ob

se

rva

tio

ns

<=

4.9

2

9.9

3 - 1

4.9

2

19

.98

- 24

.97

29

.98

- 34

.97

39

.98

- 44

.97

49

.98

- 54

.97

59

.98

- 64

.97

69

.98

- 74

.97

77

.98

- 84

.97

89

.98

- 94

.97

99

.98

- 10

4.9

7

Hydrogen Ion Concentration Residual Distribution


Discussion of results

Both heritability estimates would be considered relatively high

Greater genetic progress would be expected if selection were based on H+ concentration rather than pH

The Pearson correlation ( -0.92) between the pH and H+ concentration breeding values was expected


Discussion of results cont’

Spearman rank correlation between the breeding values for pH and H+ concentration was -0.85

While relatively strong, the rank correlation does indicate that some difference in ranking of sires is likely to occur depending whether they are ranked based on pH or H+ concentration breeding values


Example truncation selection for pH and Hydrogen ion concentration based on top 5 percent breeding values.


Example truncation selection for pH and Hydrogen ion concentration based on top 1, 5, and 25% percent breeding values.

H+ Selection differential

SelectionIntensity

Select on pHSelect on H+

SelectionDifferential

Selectiondifferential loss, %

25% -0.78 -0.82 -0.04 4.8

5% -1.80 -1.93 -0.13 6.7

1% -2.53 -2.91 -0.38 13.1

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits.

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Transcript of I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits.