Genetic Evaluation of Stillbirth in US Holsteins Using a Sire-maternal Grandsire Threshold Model
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Genetic Evaluation of Stillbirth in US Holsteins Using a Sire-maternal Grandsire Threshold Model

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My talk on the implementation of a national genetic evaluation for stillbirth at the 8th World Congress on Genetics Applied to Livestock Production in Belo Horizonte, Brazil.

My talk on the implementation of a national genetic evaluation for stillbirth at the 8th World Congress on Genetics Applied to Livestock Production in Belo Horizonte, Brazil.

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Genetic Evaluation of Stillbirth in US Holsteins Using a Sire-maternal Grandsire Threshold Model Presentation Transcript

  • 1. 200 6 J.B. Cole,* G.R. Wiggans, and P.M. VanRadenJ.B. Cole,* G.R. Wiggans, and P.M. VanRaden Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD jcole@aipl.arsusda.gov Genetic Evaluation of Stillbirth in USGenetic Evaluation of Stillbirth in US Holsteins Using a Sire-maternalHolsteins Using a Sire-maternal Grandsire Threshold ModelGrandsire Threshold Model
  • 2. 8th WCGALP, Belo Horizonte, Brazil 2006 (2) Cole et al. 200 6 IntroductionIntroduction  Stillbirth is a genetically-controlled trait.  Producers are concerned about stillbirth.  Calf livability scores are already delivered with calving ease data.  Participation in Interbull evaluations for both calving ease (CE) and stillbirth (SB) is desirable.
  • 3. 8th WCGALP, Belo Horizonte, Brazil 2006 (3) Cole et al. 200 6 Stillbirth DefinitionStillbirth Definition  Reported on a three-point scale:  Scores of 2 and 3 are combined. 1 = calf born alive, 2 = calf born dead, 3 = calf died within 48 h of parturition.
  • 4. 8th WCGALP, Belo Horizonte, Brazil 2006 (4) Cole et al. 200 6 Data and EditsData and Edits  6 million SB records were available for Holstein cows calving since 1980.  Herds needed ≥10 calving records with SB scores of 2 or 3 for inclusion.  Herd-years were required to include ≥20 records.  Only single births were used (no twins).
  • 5. 8th WCGALP, Belo Horizonte, Brazil 2006 (5) Cole et al. 200 6 Stillbirth DataStillbirth Data Alive Dead Died Usable Parity 1 2 3 Records 1 88.6% 10.9% 0.5% 1,596,693 2+ 94.7% 4.8% 0.5% 4,448,187 Usable Records 5,627,952 387,606 29,322 6,044,880 Stillbirth Score
  • 6. 8th WCGALP, Belo Horizonte, Brazil 2006 (6) Cole et al. 200 6 Genetic Evaluation ModelGenetic Evaluation Model  A sire-maternal grandsire (MGS) threshold model was used: • Fixed: year-season, parity-sex, sire and MGS birth year; • Random: herd-year, sire, MGS.  (Co)variance components were estimated by Gibbs sampling. • Heritabilities are 3.0% (direct) and 6.5% (MGS). ijklnoprnplonlkjiijklnopr emsBMBSPSYShyy +++++++= ijklnoprnplonlkjiijklnopr emsBMBSPSYShyy +++++++= ijklnoprnplonlkjiijklnopr emsBMBSPSYShyy +++++++=
  • 7. 8th WCGALP, Belo Horizonte, Brazil 2006 (7) Cole et al. 200 6 Trait DefinitionTrait Definition  PTA are expressed as the expected percentage of stillbirths.  Direct SB measures the effect of the calf itself.  Maternal SB measures the effect of a particular cow (daughter).  A base of 8% was used for both traits:  Direct: bulls born 1996–2000;  Maternal: bulls born 1991–1995.
  • 8. 8th WCGALP, Belo Horizonte, Brazil 2006 (8) Cole et al. 200 6 Phenotypic Trend for StillbirthsPhenotypic Trend for Stillbirths 0 2 4 6 8 10 12 14 1980 1983 1986 1989 1992 1995 1998 2001 2004 Birth Year %Stillbirth Heifers Cows All animals
  • 9. 8th WCGALP, Belo Horizonte, Brazil 2006 (9) Cole et al. 200 6 Genetic Trend for StillbirthsGenetic Trend for Stillbirths 5.0 6.0 7.0 8.0 9.0 10.0 1980 1985 1990 1995 2000 Birth Year %SBH Direct Maternal
  • 10. 8th WCGALP, Belo Horizonte, Brazil 2006 (10) Cole et al. 200 6 Distribution of PTADistribution of PTA 0 5 10 15 20 25 30 35 40 6.1-6.56.6-7.07.1-7.57.6-8.08.1-8.58.6-9.09.1-9.59.6-10.0 10.1-10.510.6-11.011.1-11.511.6-12.0 >12.0 %SBH PercentofScores Direct Maternal
  • 11. 8th WCGALP, Belo Horizonte, Brazil 2006 (11) Cole et al. 200 6 Distribution of ReliabilitiesDistribution of Reliabilities 0 5 10 15 20 25 30 35 40 45 50 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96-99 Reliability Percentage Direct Maternal
  • 12. 8th WCGALP, Belo Horizonte, Brazil 2006 (12) Cole et al. 200 6 Dystocia and StillbirthDystocia and Stillbirth  Meyer et al. (2001b) make a strong argument for the inclusion of dystocia in models for SB.  Difficulty of interpretation - formidable educational challenge.  Interbull trait harmonization - none of the March 2006 test run participants included dystocia in their models.  Changes in sire and MGS solutions on the underlying scale between models were small.
  • 13. 8th WCGALP, Belo Horizonte, Brazil 2006 (13) Cole et al. 200 6 Correlations among domestic andCorrelations among domestic and Interbull SB solutionsInterbull SB solutions ((≥≥90% Rel on both scales)90% Rel on both scales) Direct Maternal Switzerland 0.90 0.85 Denmark 0.78 0.75 Finland 0.65 0.96 Netherlands 0.71 0.69 Sweden 0.63 0.89
  • 14. 8th WCGALP, Belo Horizonte, Brazil 2006 (14) Cole et al. 200 6 Genetic Correlations Among SB and CEGenetic Correlations Among SB and CE Trait CE SB Direct Maternal Direct Maternal CE Direct 1.00 0.46 0.67 0.25 Maternal 1.00 0.29 0.63 SB Direct 1.00 0.28 Maternal 1.00
  • 15. 8th WCGALP, Belo Horizonte, Brazil 2006 (15) Cole et al. 200 6 Calving Ability IndexCalving Ability Index  CA$ has a genetic correlation of 0.85 with the combined direct and maternal CE values in 2003 NM$ and 0.77 with maternal CE in TPI.  Calving traits receive 6% of the total emphasis in NM$ (August 2006 revision). (DCE ) (MCE ) (DSB ) (MSCA$ B )= − − − − − − − −4 8 3 8 4 8 8 8
  • 16. 8th WCGALP, Belo Horizonte, Brazil 2006 (16) Cole et al. 200 6 ConclusionsConclusions  Number of SB records (6 million) was about half of calving ease records (14 million).  Reliabilities for SB averaged 45% versus 60% for CE.  Phenotypic and genetic trends from 1980 to 2005 were both small.  An industry-wide effort is underway to improve recording of calf livability.
  • 17. 8th WCGALP, Belo Horizonte, Brazil 2006 (17) Cole et al. 200 6 ConclusionsConclusions  A routine evaluation for stillbirth in US Holsteins was implemented in August 2006.  Direct and maternal stillbirth were included in NM$ for Holsteins starting in August 2006.  August 2006 data were sent to Interbull for the September 2006 test run for calving traits.  The US will participate in routine Interbull evaluations beginning in November 2006.
  • 18. 8th WCGALP, Belo Horizonte, Brazil 2006 (18) Cole et al. 200 6 AcknowledgmentsAcknowledgments  Jeff Berger, Iowa State University  John Clay, Dairy Records Management Systems  Ignacy Misztal and Shogo Tsuruta, University of Georgia