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10-637 Animal Models
Lesson 8 Assignment

L. R. Schaeffer, March 1999

Do any two of the following four questions. You can earn extra marks by doing all four (to make up for lost marks on previous or later assignments).

1.
Dairy bulls that were used in artificial insemination from 1975 through 1985 were measured for levels of a particular blood constituent, call it BC. Of interest to the industry is the relationship of BC levels with genetic evaluations for protein yield. Write a model that could be used for this study. Identify the fixed and random factors and structure of the variance-covariance matrices.

2.
Muscle area of the longisimus dorsi in beef cattle is a trait of economic importance. Bull and steer calves of many breeds are usually slaughtered at a desired level of backfat thickness. The bulls and steers of different breeds mature at different rates and thus, are slaughtered at different ages. Write a model for computing genetic evaluations for muscle area.

3.
Below are antler weights on deer raised in Ontario. The antlers are sold in Toronto for export to Japan and China. Assume that the model equation is

\begin{displaymath}Weight = \mu + (Herd-Year) + Age + e. \end{displaymath}

Set up \({\bf X}\) and assume that the residual variance depends on the age of the animal when you write \({\bf R}\).
Herd Year Age(yr) Weight(kg)
1 89 2 10.7
1 89 2 11.3
1 89 3 14.6
1 90 4 16.3
1 90 5 17.1
1 90 3 15.4
1 91 5 18.8
1 91 4 16.5
2 89 2 9.4
2 89 2 8.2
2 89 4 14.7
2 90 3 13.9
2 90 5 15.6
4.
Pick an appropriate genetics and breeding paper in the Journal of Animal Science, the Journal of Dairy Science, or some other source. Re-write the model in your own words and give all three parts of the model (even if the authors did not).


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This LaTeX document is available as postscript or asAdobe PDF.

Larry Schaeffer
1999-02-26