1. Adjustment of breeding values for past and future inbreeding Paul VanRaden*, Lori Smith Animal Improvement Programs Laboratory Agricultural Research Service, USDA Beltsville, Maryland

2. ADSA 1999 (2) P. M. VanRaden Selection and Mating Selection Selection – Rank animals from best to worst – Decide which animals reproduce Mating Mating – Predict the merit of pairs – Decide which animals are paired Select/Mate Select/Mate – Do both steps at once – Better in theory but not practical

3. ADSA 1999 (3) P. M. VanRaden Main effects and interactions Transmitting ability Transmitting ability – Mean value of progeny of random mates – Falconer Nonadditive merit Nonadditive merit – Parents’ combined value minus parent average – Inbreeding depression Best Transmitting Ability Best Transmitting Ability – Value of progeny of least related mates – Value of genes in later generations

4. ADSA 1999 (4) P. M. VanRaden Past and future inbreeding Past inbreeding Past inbreeding adjusted yield = yield -  (inbreeding) adjusted yield = yield -  (inbreeding) Future inbreeding Future inbreeding adjusted PTA = PTA +  (expected inbreeding) adjusted PTA = PTA +  (expected inbreeding) combined merit = PTA S + PTA D +  (inbreeding S,D ) combined merit = PTA S + PTA D +  (inbreeding S,D ) PTA S and PTA D are adjusted for past inbreeding PTA S and PTA D are adjusted for past inbreeding Mating programs Mating programs

5. ADSA 1999 (5) P. M. VanRaden Test of adjustments Mate population Mate population – 600 females born in 1996 Data file Data file – All Holsteins evaluated August 1998 Regressions Regressions – Previously estimated by Wiggans et al. (1995) Timing Timing – 4 hours for expected inbreeding; 0 for evaluation

6. ADSA 1999 (6) P. M. VanRaden PTA Correlations None PastPast, Future None PastPast, Future None1.0000.9974.9976 Past.99741.0000.9976 Past, Future.9976.9976 1.0000 Adjustments From 584 active AI bulls

7. ADSA 1999 (7) P. M. VanRaden Value of adjustment Current progress = $200 million/yr Current progress = $200 million/yr Increased progress = 100/(1-.9976) =.24% Increased progress = 100/(1-.9976) =.24% Yearly benefit = $.5 million/yr Yearly benefit = $.5 million/yr Net present value = $10 million/yr Net present value = $10 million/yr

8. ADSA 1999 (8) P. M. VanRaden Genetic Trend Cows born 1980-1990 kg/year Published trend104.4 Additive trend107.4 Additive - inbreeding loss 98.2

9. ADSA 1999 (9) P. M. VanRadenInterbull Ideal Ideal – Each country adjusts for past inbreeding – Do across-country evaluation (MACE) – Add future inbreeding within country Proposed Proposed – USA adjusts for past and future inbreeding – MACE accounts for change in trend Alternative Alternative – Adjust only the Net Merit index

10. ADSA 1999 (10) P. M. VanRaden Conclusions Additive and nonadditive effects can be separated Additive and nonadditive effects can be separated PTAs may include expected nonadditive (expected inbreeding  0) PTAs may include expected nonadditive (expected inbreeding  0) Trends change more than rank Trends change more than rank Uniform policy best for Interbull Uniform policy best for Interbull

11. ADSA 1999 (11) P. M. VanRadenImplementation Adjustments easy for U.S. bulls. Adjustments easy for U.S. bulls. Foreign pedigree may be missing. Foreign pedigree may be missing. Can’t add future inbreeding if foreign PTA includes past inbreeding Can’t add future inbreeding if foreign PTA includes past inbreeding Adjust for past and future in September Interbull test run. Adjust for past and future in September Interbull test run. Hope MACE converts to new scale. Hope MACE converts to new scale.