1. 2005 Paul VanRaden Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov An Example from Dairy Cattle Selection: The Net Merit Index

2. BIF 2005 (2) VanRaden 2005 The Old Way of Selecting Cattle

3. BIF 2005 (3) VanRaden 2005 Objectives  Document USA Net Merit index  Compare national selection indexes for dairy cattle  Discuss traits that affect profit and direction of selection  Outline approach for estimating economic values

4. BIF 2005 (4) VanRaden 2005 Selection Theory  Progress = accuracy  intensity  genetic SD / generation interval  Multiply above by directional loss Accuracy = Corr (EBV, BV) Directional loss = Corr (e EBV, a EBV) Estimated (e) vs. actual (a) economic values  Direction may be the most important factor

5. BIF 2005 (5) VanRaden 2005 Direction of Selection Trait 1 Trait 2 Accuracy contours Animals selected

6. BIF 2005 (6) VanRaden 2005 Trait Direction Not Clear  Concentrated (less) or diluted (more) milk?  Large or small cows?  Skinny or fat cows?  Dairy or beef or dual purpose? Can change direction by replacing a population instead of selecting within Specialized populations can be useful

7. BIF 2005 (7) VanRaden 2005 Coefficients of variation (CV) Trait Herit- ability CV (%) Pheno- typic Genetic Stature.42 3 2 Protein yield.30137 Longevity.085416 Fertility.046513

8. BIF 2005 (8) VanRaden 2005 Measures of accuracy Averages for recently proven Holstein bulls Trait ACC r BV,EBV REL r 2 EBV,BV BIF ACC 1 -  1-r 2 Protein yield.92.85.61 SCS (mastitis).77.59.36 Productive life.78.61.38 Cow fertility.75.56.34 Calving Ease.85.72.47

9. BIF 2005 (9) VanRaden 2005 Relative Emphasis  Easily compare selection goals independent of trait units Trait economic value times genetic SD Divide by the sum across all traits Multiply by 100  Expresses relative emphasis as percent of total selection Added traits decrease emphasis on others Convenient way to display indexes

10. BIF 2005 (10) VanRaden 2005 History of USDA economic indexes (PD$, MFP$, CY$, and NM$) and Holstein Association TPI Year Introduced and Index Name 19711976197719801984198719891992199419972000 TraitPD$TPIMFP$TPICY$TPI NM$TPI NM$ Protein275340345043504136 Fat48464540341725171621 Milk52602760-2 6 5 % Fat20 Longevity201314 SCS 6 1 9 Udder17 11 9 7 Feet / legs 5 5 4 Size -4 Final Score4020 17 14

11. BIF 2005 (11) VanRaden 2005 Current National Selection Indexes: Yield and Health Traits Country (Interbull Code) USADEUFRANZLNLDCANGBRAUSITADNKSWE % of Interbull Population 17.415.312.310.69.34.7 4.54.34.1 1.5 Index NameNM$TPIRZGISUBWDPSLPIPLIAPRPFTS – ITMI Trait Protein 3332363534323157364221 Fat 2218910137201112 104 Milk -17-12-19-20-3-4 % Protein 4223 % Fat 1212 Longevity 11825138871512866 SCS / mastitis 955131437101512 Fertility 7521310 59 Other diseases 23

12. BIF 2005 (12) VanRaden 2005 Current National Selection Indexes: Conformation and Management Traits Country (Interbull Code) USADEUFRANZLNLDCANGBRAUSITADNKSWE % of Interbull Population 17.415.312.310.69.34.7 4.54.34.11.5 Index NameNM$TPIRZGISUBWDPSLPIPLIAPRPFTS – ITMI Trait Udder traits710681613912 Feet / legs4541511659 Size-322-18-54-42 Dairy character-22 Rump11 Final score1342 Calving ease4247612 Growth / meat46 Milking Speed <146 Temperament523

13. BIF 2005 (13) VanRaden 2005 Milk Pricing and Feed Cost ($ per pound) IndexMilkFatProtein Fluid Merit.0511.301.00 Net Merit.0121.302.30 Cheese Merit-.0091.303.00 Feed Cost-.012-.35-.50

14. BIF 2005 (14) VanRaden 2005 Value of Cow Fertility  Daughter pregnancy rate (DPR) Pregnancies achieved per 21-day cycle 1% higher DPR = 4 fewer days open  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

15. BIF 2005 (15) VanRaden 2005 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

16. BIF 2005 (16) VanRaden 2005 Linear vs Non-linear Profit Calculation of Net Merit $  Non-linear profit = (income – expense per lactation) number of lactations + cull value – raising cost  Linear profit obtained by taking partial derivatives at trait means  Corr (linear, non-linear) =.999

17. BIF 2005 (17) VanRaden 2005 Lifetime Net Merit $  Incomes and expenses estimated from yield traits, SCS, longevity, fertility, conformation, calving ease  Example: body size Convert from visual scores to weight Cull price - growth cost + lactations  (calves – maintenance) = $-1.28 / kg Less beef = more profit to dairy farmer

18. BIF 2005 (18) VanRaden 2005 Goals of Index Calculation  Give breeders the index they want Breed association or AI committees Emotional approach (TPI)  Give scientists the index they want Add incomes, subtract expenses Mathematical approach (NM$)  Future prices difficult to prove

19. BIF 2005 (19) VanRaden 2005 Top Net Merit Bulls May 2005 BullCntryDtrs NM$ REL Net Merit $ Pro- tein O ManUSA2309372957 Loe MartinNLD1667465779 LombardDEU937065573 MascolDEU986864559 MarionUSA567661374 S D JordanNLD1207659561 AltonUSA978258555

20. BIF 2005 (20) VanRaden 2005 Trait Harmonization Mark, 2003 EAAP meeting Trait Coun- tries Average corr. Avg. cor w / USA Protein27.87.89 Stature21.89.90 Fore Udder21.75.79 SCS20.85.86 Longevity14.59.74 D. CalvEase10.83.86 M. CalvEase10.58.64

21. BIF 2005 (21) VanRaden 2005 Paul’s Beef Experience

22. BIF 2005 (22) VanRaden 2005 Interbull Beef Proposal  Provide international evaluations within ICAR subcommittee  Combine raw data files instead of national evaluations  Favorable responses received from many countries  Charolais, Limousin most likely

23. BIF 2005 (23) VanRaden 2005 Conclusions - Dairy  Many traits in addition to yield contribute to dairy cattle profit  Longevity, fertility, health, and type traits get half of emphasis  Direction unclear for some traits  Indexes began in 1970’s and have improved rapidly in recent years

24. BIF 2005 (24) VanRaden 2005 Conclusions - Beef  An official, published goal: Stimulates economic research Gives breeders direction  An overall index helps breeders: Promote their own animals Locate superior breeding stock Compete to improve the breed