1. 2006 J.B. Cole,* G.R. Wiggans, and P.M. VanRaden Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD jcole@aipl.arsusda.gov@aipl.arsusda.gov Genetic Evaluation of Stillbirth in US Holsteins Using a Sire-maternal Grandsire Threshold Model

2. 8th WCGALP, Belo Horizonte, Brazil 2006 (2) Cole et al. 2006 Introduction  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. 2006 Stillbirth 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. 2006 Data 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. 2006 Stillbirth Data AliveDeadDiedUsable Parity123Records 188.6%10.9%0.5%1,596,693 2+94.7%4.8%0.5%4,448,187 Usable Records 5,627,952387,60629,3226,044,880 Stillbirth Score

6. 8th WCGALP, Belo Horizonte, Brazil 2006 (6) Cole et al. 2006 Genetic 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).

7. 8th WCGALP, Belo Horizonte, Brazil 2006 (7) Cole et al. 2006 Trait 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. 2006 Phenotypic Trend for Stillbirths

9. 8th WCGALP, Belo Horizonte, Brazil 2006 (9) Cole et al. 2006 Genetic Trend for Stillbirths

10. 8th WCGALP, Belo Horizonte, Brazil 2006 (10) Cole et al. 2006 Distribution of PTA

11. 8th WCGALP, Belo Horizonte, Brazil 2006 (11) Cole et al. 2006 Distribution of Reliabilities

12. 8th WCGALP, Belo Horizonte, Brazil 2006 (12) Cole et al. 2006 Dystocia 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. 2006 Correlations among domestic and Interbull SB solutions (≥90% Rel on both scales) DirectMaternal Switzerland0.900.85 Denmark0.780.75 Finland0.650.96 Netherlands0.710.69 Sweden0.630.89

14. 8th WCGALP, Belo Horizonte, Brazil 2006 (14) Cole et al. 2006 Genetic Correlations Among SB and CE Trait CESB DirectMaternalDirectMaternal CE Direct1.000.460.670.25 Maternal1.000.290.63 SB Direct1.000.28 Maternal1.00

15. 8th WCGALP, Belo Horizonte, Brazil 2006 (15) Cole et al. 2006 Calving 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).

16. 8th WCGALP, Belo Horizonte, Brazil 2006 (16) Cole et al. 2006 Conclusions  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. 2006 Conclusions  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. 2006 Acknowledgments  Jeff Berger, Iowa State University  John Clay, Dairy Records Management Systems  Ignacy Misztal and Shogo Tsuruta, University of Georgia