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Breed and Trait Selection Considerations
Dan W. MoserDan W. Moser
Dept. of Animal Sciences and Dept. of Animal Sciences and IndustryIndustry
Kansas State UniversityKansas State University
Outline
Breed Selection ConsiderationsBreed Selection Considerations GeneralGeneral Seedstock-SpecificSeedstock-Specific
Trait Selection ConsiderationsTrait Selection Considerations GeneralGeneral Commercial-SpecificCommercial-Specific Seedstock-SpecificSeedstock-Specific
Breed Selection Considerations
Genetic Merit / Breeding ValueGenetic Merit / Breeding Value Breed ComplimentarityBreed Complimentarity Specific Heterosis (Combining Specific Heterosis (Combining
Ability)Ability) Uniformity of OffspringUniformity of Offspring Maternal/Terminal RolesMaternal/Terminal Roles Breed DirectionBreed Direction
Breed Selection Considerations
Genetic AntagonismsGenetic Antagonisms Genetic EvaluationGenetic Evaluation Other Breed-Specific ServicesOther Breed-Specific Services Market Realities and PerceptionsMarket Realities and Perceptions Dynamic Nature of the IndustryDynamic Nature of the Industry External FactorsExternal Factors
Genetic Merit of Breeds
WW
Breed Average Across-Breed EPD
AngusBeefmasterBrangusCharolaisGelbviehHerefordLimousinRed AngusSimmental
Van Vleck and Cundiff, 2003
Genetic Merit of Breeds
Breeds differ for:Breeds differ for: MaintenanceMaintenance ReproductionReproduction CarcassCarcass
Genetic merit must match Genetic merit must match production environment.production environment.
Some economically relevant traits Some economically relevant traits go unmeasured.go unmeasured.
Unmeasured/Unreported Traits
Mature cow sizeMature cow size Reproductive dataReproductive data Feed intakeFeed intake Shear forceShear force
Specific Heterosis
A “Lost Science”?A “Lost Science”? Not all heterosis is created equallyNot all heterosis is created equally Depends on the genetic similarity Depends on the genetic similarity
of the breeds being crossedof the breeds being crossed Just as traits vary in heritability, Just as traits vary in heritability,
traits also vary in effects of traits also vary in effects of heterosisheterosis
Specific HeterosisSurvival to Weaning, Direct, %
ANAN CHCH GVGV HHHH LM LM
CHCH 2.012.01
GVGV 2.142.14 1.691.69
HHHH 2.522.52 2.772.77 3.493.49
LMLM 1.881.88 0.890.89 2.012.01 3.253.25
SMSM 1.281.28 1.051.05 1.121.12 2.822.82 1.281.28
Roughsedge et al., 2001
Specific HeterosisPost Weaning Gain, %
ANAN CHCH GVGV HHHH LM LM
CHCH 4.644.64
GVGV 4.944.94 3.913.91
HHHH 5.825.82 6.406.40 8.088.08
LMLM 4.354.35 2.062.06 4.644.64 7.517.51
SMSM 2.962.96 2.422.42 2.602.60 6.516.51 2.962.96
Roughsedge et al., 2001
Specific HeterosisCow Fertility, %
ANAN CHCH GVGV HHHH LM LM
CHCH 7.747.74
GVGV 8.248.24 6.526.52
HHHH 9.709.70 10.6810.68 13.4713.47
LMLM 7.257.25 3.443.44 7.747.74 12.5212.52
SMSM 4.944.94 4.034.03 4.334.33 10.8610.86 4.944.94
Roughsedge et al., 2001
Breed Complimentarity
Combine breeds to overcome Combine breeds to overcome antagonismsantagonisms
Not the Not the bestbest of both, but the of both, but the averageaverage of both, plus heterosis of both, plus heterosis
Breed Complimentarity
WW MILK
Breed Average Across-Breed EPD
AngusCharolaisGelbviehHerefordLimousinRed AngusSimmental
Van Vleck and Cundiff, 2003
Breed Complimentarity
Rotational crossing using Rotational crossing using purebred sires that differ in purebred sires that differ in biological type:biological type: benefits from complimentaritybenefits from complimentarity reduces uniformity (across the reduces uniformity (across the
calf crop)calf crop)
Breed Complimentarity
Crossing purebred sires of Crossing purebred sires of different breeds but similar different breeds but similar biological type:biological type: improves uniformityimproves uniformity reduces complimentarityreduces complimentarity may reduce effects of heterosismay reduce effects of heterosis
Breed Complimentarity
Hybrids and composites have the ability Hybrids and composites have the ability to offer both complimentarity and to offer both complimentarity and uniformityuniformity Only a slight reduction in heterosis Only a slight reduction in heterosis
compared to using purebred sirescompared to using purebred sires All calves are same breed compositionAll calves are same breed composition Also simplifies execution of the Also simplifies execution of the
crossbreeding systemcrossbreeding system
Breed Selection: Seedstock
Rarely do seedstock operators Rarely do seedstock operators completely change breeds.completely change breeds.
Opportunities exist to:Opportunities exist to: Add breedsAdd breeds Add FAdd F11’s’s Add compositesAdd composites
Evolution of Seedstock ProductionPurebred, Single Breed
Purebred, Multi-Breed
Purebred (Multi-Breed) and F1
Purebred (Multi-Breed), F1, and
Composite
Weaning WeightGenetic Trend
0
5
10
15
20
25
30
35
80 85 90 95 00
Calf Year of Birth
EP
D (
Po
un
ds
)
HerefordAngusSimmentalCharolais
Maternal MilkGenetic Trend
-2
0
24
6
8
10
1214
16
18
80 85 90 95 00
Calf Year of Birth
EP
D (
Po
un
ds
)
HerefordAngusSimmentalCharolais
Trait Selection Considerations
Economic ImportanceEconomic Importance Heritability and HeterosisHeritability and Heterosis Method of Multiple Trait SelectionMethod of Multiple Trait Selection Genetic AntagonismsGenetic Antagonisms Maternal/Terminal RolesMaternal/Terminal Roles Market Realities and PerceptionsMarket Realities and Perceptions Dynamic Nature of the IndustryDynamic Nature of the Industry
Heritability
Portion of a trait’s variation Portion of a trait’s variation attributable to additive geneticsattributable to additive genetics
In general, heritability is:In general, heritability is: High for carcass traits and High for carcass traits and
mature sizemature size Moderate for growth rate and Moderate for growth rate and
milk productionmilk production Low for reproductive traitsLow for reproductive traits
Heritability
Highly heritable traits are the Highly heritable traits are the easiest to change with selectioneasiest to change with selection
Traits that are low in heritability can Traits that are low in heritability can be changed with selection, but be changed with selection, but change is slower change is slower
Heritability of a trait is reflected in Heritability of a trait is reflected in the range of EPD across a populationthe range of EPD across a population
Heterosis
TraitTrait %HV%HVII %HV%HVMM %HV%HVPP
Birth WeightBirth Weight 3.03.0 1.51.5 --
Weaning WeightWeaning Weight 5.05.0 8.08.0 --
Calves weaned/cow Calves weaned/cow exp.exp.
3.03.0 8.08.0 5.05.0
Lbs. weaned/cow Lbs. weaned/cow exp.exp.
7.07.0 15.015.0 6.06.0
Feed Conversion Feed Conversion (F/G)(F/G)
-1.0-1.0 -- --
Age at PubertyAge at Puberty -5.5-5.5 -- --
Bourdon, 2000
Heritability vs. Heterosis
Logical for commercial producers to:Logical for commercial producers to: Select mainly for moderate and Select mainly for moderate and
highly heritable traitshighly heritable traits Depend on heterosis to ensure Depend on heterosis to ensure
adequate levels of traits low in adequate levels of traits low in heritabilityheritability
Seedstock producers cannot ignore Seedstock producers cannot ignore traits that are low in heritabilitytraits that are low in heritability
Methods ofMultiple-Trait Selection Independent Culling LevelsIndependent Culling Levels
Most commonly usedMost commonly used Set min/max levels for each trait Set min/max levels for each trait
(EPD)(EPD) Selection IndexSelection Index
Most effective for overcoming Most effective for overcoming antagonismsantagonisms
Weight traits (EPD) on economic Weight traits (EPD) on economic importanceimportance
Independent Culling Levels
Possible to “just miss” some bulls Possible to “just miss” some bulls that offer superior genetic that offer superior genetic combinationscombinations
Limit the ability to overcome Limit the ability to overcome antagonismsantagonisms
Selection Index
Fairly straightforward for terminal Fairly straightforward for terminal siressires
Much more complex for maternal Much more complex for maternal lineslines
Currently applied in other species, Currently applied in other species, and for beef on other continentsand for beef on other continents
Selection Index
Selection Index is fairly robust.Selection Index is fairly robust. Need the ability to enter index weights Need the ability to enter index weights
into sire sort web pages…into sire sort web pages… Or at least download sire summaries Or at least download sire summaries
in a spreadsheet format.in a spreadsheet format. Precise economic weights are under Precise economic weights are under
development, are we ready to apply development, are we ready to apply them?them?
