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Planned Changes to Models and Trait Definitions

Discover the latest improvements in livestock modeling and trait definitions, including adjustments for inbreeding, age factors, longevity, and more. Stay informed on calving ease changes and genetic correlations in this comprehensive update.

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Planned Changes to Models and Trait Definitions

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  1. Planned Changes to Models and Trait Definitions

  2. November 2004 Changes • Pregnancy checks used in days open predictions (130-250 DIM) • Longevity for foreign Holstein bulls • Single-trait longevity from Interbull • Multi-trait processing at AIPL • Foreign bull mean PL REL = 46% (was 38%), NM$ REL = 72% (was 71%) • 15 countries (Other breeds Feb. 2005)

  3. 2005 Trait and Model Changes • Adjust for past inbreeding (F) and expected future inbreeding (EFI) • Adjust for differing parity SD • Express yield PTA to 36-month age instead of mature equivalent • Use cow instead of bull base for DPR • Use 3.00 instead of breed means for SCS

  4. SCS Breed Means and Bases

  5. Daughter Pregnancy Rate Bases

  6. Inbreeding AdjustmentsVanRaden and Smith, 1999, JDS 82:2771 • F (past inbrd.) and EFI (future inbrd.) • Regression on F in animal model (PTA0) • PTAEFI = PTA0 + EFI * byield.F • Corr (current PTA, PTAEFI) = .9976 • Genetic trend for PTAEFI is reduced • Yield trend 6% less, DPR 14% lower, PL 25% lower, SCS becomes slightly unfavorable • Predict NM$EFI = NM$ + 7 (Fdaus) – 14 (EFI)

  7. Use in Mating Programs • Replace EFI with progeny F • PA NM$ = (NM$sire + NM$dam)/2 • Progeny merit = PA NM$ – 14 [Fprog - (EFIsire - EFIdam)/2] • Similar to calving ease • NM$ includes average value of SCE • SCE has higher value for heifer matings, lower for cow matings

  8. Parity SD Adjustments • Multiplicative or additive adjustments? • Neither makes variances quite equal • Combined approach (Funk et al, 1991 JDS) • Lactation 1-5 deviations multiplied by • [1.06 .99 .94 .89 .85] (milk, fat, protein) • [ .97 .99 1.01 1.02 1.02] (SCS) • [1.03 1.00 .98 .97 .96] (DPR) • Helps pass Interbull trend test 1 • Corr (official, adjusted PTA) = .9998

  9. Age Adjustment for Yield PTA • Use 36 months vs. mature equivalent • Standardized and actual means similar • Age factors are estimated more precisely • More fair when breed maturity rates differ • Proposed previously by USDA • McDaniel (1973, JDS 56:959), Schutz (1994) • Recommended by Holstein GAC, Oct 1994 • Vetoed by Council in 1994 “to allow the industry time to consider the nature and effect of such a change.”

  10. Breed SD and Maturity Rates Age factors from Schutz, 1994

  11. Actual vs Standardized Means(current CA data, all lactations)

  12. Genetic Trend 1995-2000(cow birth year)

  13. Calving Ease Changes (Feb. 2005) • Joint BSW-HOL evaluation (pending NAAB approval) • 11,793 BSW, 3431 BSW-HOL calvings • 12 million HOL calvings • Includes breed-of-MGS effect • Uses HOL (co)variance components and breed-specific bases

  14. Calving Ease Model Validation • Results passed Interbull trend validation • Joint BSW-HOL results compared to single-breed evaluations • Correlations showed BSW data did not adversely affect HOL results.

  15. Within-breed vs Joint Evaluation

  16. Summary for Calving Ease

  17. Future Research • Genetic evaluation of crossbreds • Productive life trait definition • Lactation length, yield correlations • Trend tests prevent inbreeding adj. • Yield trait model improvements • Mendelian sampling variance • Persistency, rate of maturity

  18. Summary • Longevity from Interbull in Nov 2004 • Brown Swiss calving ease in Feb 2005 • Adjustments for inbreeding and for differing parity SD in Feb 2005 • Age adjustment to 36 months instead of mature will affect breed means and SD

  19. Longevity Genetic CorrelationsInterbull, Sept. 2004

  20. Sire Calving Ease CorrelationsInterbull, Oct. 2004

  21. Daughter Calving Ease CorrelationsInterbull, Oct. 2004

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