1. Paul VanRaden Animal Improvement Programs Laboratory Beltsville, MD, USA paul@aipl.arsusda.gov 2004 2005 Inbreeding Adjustments and Effect on Genetic Trend Estimates

2. INTERBULL ANNUAL MEETING 2005 (2)P.M. VanRaden 20042005 Adjustments Introduced Feb 2005  Inbreeding depression:  Remove by regression in animal model  Then include expected future inbreeding  EFI =.5 mean relationship to current cows  Parity variance  Heterogeneous variance refinement  September 2004 test run included both

3. INTERBULL ANNUAL MEETING 2005 (3)P.M. VanRaden 20042005 Inbreeding Adjustments VanRaden and Smith 1999 JDS 82:2771  Subtract regression (b) from y  YD 0 = y - m - p - c - b (F cow )  DYD 0 and PTA 0 reflect 0 inbreeding  Add expected future inbreeding  PTA EFI = PTA 0 + b (EFI - EFI base )  PA EFI = PA 0 + b (EFI - EFI base )  DYD EFI = DYD 0 + b (EFI - EFI base )

4. INTERBULL ANNUAL MEETING 2005 (4)P.M. VanRaden 20042005 Effects of Inbreeding Adjustment  Genetic evaluations of recent Holsteins  Corr (PTA, PTA EFI ) =.998 for bulls  Corr (PTA, PTA EFI ) =.993 for cows  Genetic correlations of USA with other countries declined by.01 (Sep 1999 test run)  Genetic trend  Yield trends were 6% lower for PTA EFI  Fertility, longevity trends 14-25% lower

5. INTERBULL ANNUAL MEETING 2005 (5)P.M. VanRaden 20042005 Changes in Trends and Trend Tests from Inbreeding Adjustments Trait Trend Change SD/yr Trend Test Differences Test 1Test 2Test 3 Protein-.018-.005.000.001 Fat-.015-.001.000 SCS.002.000 PL-.024N/A.000-.005 DPR-.009.001

6. INTERBULL ANNUAL MEETING 2005 (6)P.M. VanRaden 20042005 Parity Variance Adjustments  Trend test 1 was.014 (fail), now.008 (pass) for Jerseys. Holsteins were OK.  Deviations for yield are multiplied by [1.07 1.00.95.90.85] (parities 1-5)  Genetic trend for protein decreased by.004 genetic SD / year (2% change)  Corr (official, adjusted PTA) =.9998 for recent Holstein bulls

7. INTERBULL ANNUAL MEETING 2005 (7)P.M. VanRaden 20042005 USA vs Non-USA Bull Trends Before (Aug) and After (Sep) Adjustments Genetic Trend (SD / yr) Ratio (Non- USA / USA) USA bullsNon-USA ScaleAugSepAugSepAugSep CAN.215.209.243.2341.131.12 DEU.178.173.214.2111.201.22 FRA.189.184.221.2181.171.18 NLD.182.177.219.2141.201.21 USA.231.222.239.2261.031.02

8. INTERBULL ANNUAL MEETING 2005 (8)P.M. VanRaden 20042005 Effect on Top 100 Bulls  Average number of USA bulls in top 100 across all 27 protein scales  Increase from 24.5 to 25.3 (Holstein)  Increase from 53.8 to 56.3 (Jersey)  USA genetic trend  Decreased 6% (Holstein)  Decreased 9% (Jersey)

9. INTERBULL ANNUAL MEETING 2005 (9)P.M. VanRaden 20042005 Conclusions  Boichard et al (1995) stated that biased genetic trend “strongly disturbs international germplasm exchanges based on conversion formulas...”  MACE is robust to trend bias  Trend tests should not be required