1. 2003 P.M. VanRaden* and M.E. Tooker Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov Definition of Traits and Comparison of Models for Cow Fertility Definition of Traits and Comparison of Models for Cow Fertility

2. ADSA Annual Meeting – Cow Fertility (2)P.M. VanRaden 2003 Cow Fertility Simulation  Compare data and models Days open Log of days open Lactation pregnancy rate (1 / n) 21-day pregnancy rate (yes or no)  Population simulated 500 sires with 10 – 1000 daughters Sire effects normal for days open

3. ADSA Annual Meeting – Cow Fertility (3)P.M. VanRaden 2003 Theoretical Distribution of Days Open

4. ADSA Annual Meeting – Cow Fertility (4)P.M. VanRaden 2003 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

5. ADSA Annual Meeting – Cow Fertility (5)P.M. VanRaden 2003 Pregnancy Rate vs Days Open 0 10 20 30 40 50 60 70 80 90 100 6081102123144165186207228249 Number of Chances Pregnancy Rate 987654321 Days Open

6. ADSA Annual Meeting – Cow Fertility (6)P.M. VanRaden 2003 Simulation Results  Heritability estimates.040 for days open.035 for log (days open).029 for lactation pregnancy rate.009 (  4) for 21-day pregnancy rate  True accuracy, or corr (EBV, BV).603 for days open.585 for log (days open).566 for lactation pregnancy rate.602 for 21-day pregnancy rate

7. ADSA Annual Meeting – Cow Fertility (7)P.M. VanRaden 2003 Value of Cow Fertility  Optimum days open Pregnancy rate affects mean and variance Reduced yield/day vs longer lactations  Fertility expenses per day open Heat detection ($20 / lact .005)= $.10 Semen ($15 / unit + $5 labor) *.025= $.50 Pregnancy exam ($10 / exam)*.012= $.12 Lactations too long or short= $.75  Relative value of DPR = 7% of total

8. ADSA Annual Meeting – Cow Fertility (8)P.M. VanRaden 2003 Value of Calving Ease  Daughter CE value / difficult birth Veterinary, labor costs= $50 Calf death (20% prob)= $25 Cow deaths before 1 st test (1% prob)= $15  Service sire CE also includes Yield losses / lactation= $40 Fertility and longevity losses= $30  Relative values of each are 2% of total

9. ADSA Annual Meeting – Cow Fertility (9)P.M. VanRaden 2003 Current and Proposed Selection Indexes: Yield and Health Traits Country (Interbull Code) USA DEUFRANZLNLDCANGBRAUSITADNKSWE % of Interbull Population 17.4 15.312.310.69.34.7 4.54.34.1 1.5 Index NameNM$NewRZGISUBWDPSLPIPLIAPRPFTS – ITMI Trait Protein 3633363534354357364221 Fat 2122910138141112 104 Milk 50-17-14-19-20-3-4 % Protein 423 % Fat 122 Longevity 1411251381281512866 SCS / mastitis 995131137101512 Fertility 72131079 Other diseases 23

10. ADSA Annual Meeting – Cow Fertility (10)P.M. VanRaden 2003 Current and Proposed Selection Indexes: Conformation and Management Traits Country (Interbull Code) USA DEUFRANZLNLDCANGBRAUSITADNKSWE % of Interbull Population 17.415.312.310.69.34.7 4.54.34.11.5 Index NameNM$NewRZGISUBWDPSLPIPLIAPRPFTS – ITMI Trait Udder traits77681713912 Feet / legs4441311659 Size-4-322-184-42 Dairy character2 Rump11 Final score42 Calving ease4310612 Growth / meat46 Milking Speed <146 Temperament523

11. ADSA Annual Meeting – Cow Fertility (11)P.M. VanRaden 2003 Conclusions  Days open is right skewed but was more accurate and heritable than log or reciprocal transformations  21-day pregnancy rate had equal accuracy due to more observations but lower heritability per observation  In NM$, cow fertility will receive 7% and calving ease traits each will receive 2% of total selection

12. ADSA Annual Meeting – Cow Fertility (12)P.M. VanRaden 2003 Thank You  Tony Seykora (U. Minnesota) and Bob Miller (AIPL) helped derive an economic value for cow fertility  Many others contributed to the revision of Net Merit: Jack Dekkers, Duane Norman, Melvin Kuhn, Les Hansen, Kent Weigel, Gary Rogers, Steve Schnell, Cheryl Marti, Bennet Cassell, George Shook