1.  Docility EPD: A Tool for Temperament Devori W. Beckman Iowa State University

2. What is Docility?  Temperament – reaction of beef cattle to handling by humans (Burrow, 1997)  Why Measure Docility?  Ease of Handling  ADG  Carcass Quality  RFI

3. Measuring Docility  Flight Speed/Time, Exit Velocity  Pen Score, Docility Test, Separation Test  Chute/Crush Score

4. Scoring System BIF Guidelines (2002)

5. Docility EPD: Breed Associations  North American Limousin Foundation (NALF)  1 st Genetic Evaluation in 1998  Scores allocated at weaning  Threshold (1, 2, 3-6); h 2 = 0.40  American Angus Association (AAA)  Genetic Evaluation Spring 2008  Scores allocated at yearling  Threshold (1, 2, 3, 4-6); h 2 = 0.37 Kuehn et al. (1998); Hyde (2003); Northcutt (2007)

6. Docility EPD: Sire Comparison Example

7. Genetic Parameter Estimates For Docility In Limousin Cattle 1. Maternal (M) Effects on Docility 2. Sire by Herd (SH) Effects 3. Further Investigation of M and SH Effects

8. Recent Work: Maternal Effects Beckman et al. (2007)

9. Recent Work: Sire × Herd Notter et al. (1992); CSU - Unpublished Data

10. Objective  Do Maternal or SH effects appropriately describe docility, or are they artifacts of the nature of this data.

11. Previous Models Assumed Homogeneity Beckman et al. (2007)

12. Additional Data Filtration

14. Assessment of Heterogeneity WCGWCG AODAOD DirectDirect MaternalMaternal SHSH ResidualResidual  Step 1: Mixed Model (BASE) Analysis

15. Assessment of Heterogeneity  Step 2: Fixed Model

16. Results: Fixed Model Beckman and Garrick (2007)

17. Variance Component Estimation  Mixed Model (RESID) Analysis |ê| = Xb + Z D u D + Z M u M + Z SH u SH + e

18. Results: Variance Components Beckman and Garrick (2007)

19. Results: Variance Due to Herd

20. Conclusions 1. Maternal and SH Interaction Effects were Artifacts of the Data 2. Most of Heterogeneity Due to Herd Effects

21. Implications  Accuracy of Genetic Evaluation  Total Herd Reporting Garrick and Van Vleck (1987)

22. What’s Next?  Further Investigation of Heterogeneity  Clustering of Herds

23. Acknowledgements  North American Limousin Foundation  American Angus Association  Colorado State University  Iowa State University

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