1. 2002 Paul VanRaden, Ashley Sanders, Melvin Tooker, Bob Miller, and Duane Norman Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov Genetic Evaluation of Cow Fertility expressed as Pregnancy Rate

2. S-284, NAAB DSEC 2002 (2) P.M. VanRaden 2002 Factors Affecting Fertility  Service bull Sperm motility, abnormality, etc. measured by AI companies ERCR ratings from DRMS@Raleigh  Environment and genes of cow  Interaction of bull and cow Lethal recessives, inbreeding

3. S-284, NAAB DSEC 2002 (3) P.M. VanRaden 2002 Pregnancy Rate  Rate that cows become pregnant  Can be derived from days open Non-linear: 21 / (DO – VWP + 11) Linear approx: (233 – DO) / 4  Advantages over days open Positive numbers are desirable Earlier measure of herd fertility

4. S-284, NAAB DSEC 2002 (4) P.M. VanRaden 2002 ≤ 50 ≥ 250 Distribution of Days Open Holstein Calvings 1990 - 2001 Cows culled for reproductive reasons

5. S-284, NAAB DSEC 2002 (5) P.M. VanRaden 2002 Average breed effects across regions and time by calving month

6. S-284, NAAB DSEC 2002 (6) P.M. VanRaden 2002 Regional effects for Holsteins calving since 1997

7. S-284, NAAB DSEC 2002 (7) P.M. VanRaden 2002 Parameter Estimates Multi-trait REML analysis of first lactations Heritability of DO3.7% Correlations with DOPhenotypicGenetic Milk.11.38 Fat.09.33 Protein.10.32 SCS.05.30 PL -.20-.59

8. S-284, NAAB DSEC 2002 (8) P.M. VanRaden 2002 Pregnancy Rate Evaluation  Lactations 1-5 beginning with 1960  Data sources Reported DO confirmed with next calving – Exclude most recent 9 months Reported DO if no next calving – Exclude most recent 9 months Calving interval – 280 days if no reported DO – Exclude most recent 18 months Assigned DO = 250 if sold for infertility

9. S-284, NAAB DSEC 2002 (9) P.M. VanRaden 2002 Evaluation Methods  BLUP Animal Model  Same programs used for yield, PL, SCS  Convert to preg rate = (233 – DO) / 4  Adjust for heterogeneous variance  Parameter estimates used: Heritability = 4% Repeatability = 11% Sire-by-herd interaction = 1%

10. S-284, NAAB DSEC 2002 (10) P.M. VanRaden 2002 Evaluation Test Run  Holstein data from Aug 2002 evaluation 40 million lactations 16 million cows  Statistics for recent, well-sampled bulls Born 1994 - 1997 Milk REL > 80% (mean = 87%) 4215 Holstein bulls 314 Jersey bulls  Example evaluations for older sires

11. S-284, NAAB DSEC 2002 (11) P.M. VanRaden 2002 Recent Bull Evaluations HolsteinJersey Pregnancy Rate PTA range -4.8 to +2.8-3.0 to +1.5 REL mean 59%57% PTA correlations PL.46.23 SCS-.13.03 Milk-.22 Fat-.18-.35 Protein-.16-.17

12. S-284, NAAB DSEC 2002 (12) P.M. VanRaden 2002 Older Bull Evaluations RELDODPRPLNM$ Duster99-7+1.8+4.3+442 Bellwood99+1-.3-.5+361 Mandel99+9-2.3-.6+248 Luke99+11-2.8-1.8+135 Mountain99-3+.8+1.1+280 Mascot99+5-1.3-2.9+29

13. S-284, NAAB DSEC 2002 (13) P.M. VanRaden 2002 Pregnancy Rate Genetic Trend 1957-1999

14. S-284, NAAB DSEC 2002 (14) P.M. VanRaden 2002 Phenotypic Trend – Holstein DO 5 th 4 th 3 rd 2 nd 1 st Lactation

15. S-284, NAAB DSEC 2002 (15) P.M. VanRaden 2002 Conclusions  Daughter Pregnancy Rate has low heritability (~4%) but high genetic correlation with Productive Life (>.5)  Official evaluations for DPR planned for February 2003  Selection on PL has greatly reduced the decline in cow fertility  Economic value not yet determined

16. S-284, NAAB DSEC 2002 (16) P.M. VanRaden 2002 Acknowledgments  All DHIA herds and processing centers contributed data  George Wiggans and Lillian Bacheller improved the fertility database  John Clay suggested expressing cow fertility as pregnancy rate