2005

Paul VanRaden and Mel TookerPaul VanRaden and Mel Tooker

Animal Improvement Programs LaboratoryAgricultural Research Service, USDA, Beltsville, MDpaul@aipl.arsusda.gov

Genetic Evaluation of Genetic Evaluation of Mixed Breed PopulationsMixed Breed Populations

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GoalsGoals

Compare methods to evaluate mixed breed data• All breeds and crossbreds together• Crossbreds in breed of sire file

Compute national evaluations and examine changes• PTA’s of purebreds and crossbreds

Display results without confusion

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Options for Reporting PTAOptions for Reporting PTA

Genetic base• Each breed on its own base• Other breeds on Holstein base• All breeds on mixed breed base

Heterosis and inbreeding• PTA can include or exclude heterosis• EFI and rank differ with mate breed

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Options for ImplementationOptions for Implementation

Within breed of sire model• Further testing but fewer issues• May 2006 could be possible

All breed model• Traits in Net Merit need same base• Type and calving ease separate• November 2006 more likely

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All- vs Within-Breed EvaluationsAll- vs Within-Breed EvaluationsCorrelations of PTACorrelations of PTA

99% REL bulls

Recent bulls

Recent cows

Holstein >.999 .994 .989

Jersey .997 .988 .972

Brown Swiss .990 .960 .942

Guernsey .991 .988 .969

Ayrshire .990 .963 .943

Milking Shorthorn .997 .986 .947

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Breed Effects and HeterosisBreed Effects and HeterosisTransmitting ability differences from HolsteinTransmitting ability differences from Holstein

Milk Fat Pro SCS PL DPR

Jersey -3378 - 35 - 54 +0.15 +1.6 +2.3

Brown Sw -2235 - 43 - 37 - 0.03 +0.8 +0.1

Guernsey -3128 - 39 - 71 +0.06 - 2.0 +1.0

Ayrshire -2713 - 70 - 67 - 0.07 +0.6 +0.9

M.Shorthrn -3441 -118 - 97 - 0.09 +1.2 +2.1

Heterosis + 700 + 35 +26 +0.02 +0.3 +1.8

Heterosis and DPR estimates are from previous research

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Recent Sires of Crossbred CowsRecent Sires of Crossbred CowsSires born since 1997Sires born since 1997

Sire Daughters

Name breed Pure Cross

Advent JE 698 73

Golden JE 421 42

Eagle BS 234 35

Brendon-P JE 207 29

Big Time JE 522 28

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ConclusionsConclusions

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ConclusionsConclusions

All breed model accounts for:• Heterosis• Unknown parent groups by breed• Heterogeneous variance by breed

Breed differences well estimated PTA changed more in small breeds Breed of sire model is alternative