I. Misztal et al., IMPLEMENTATION OF SINGLE-TRAIT AND MULTIPLE-TRAIT ANIMAL-MODELS FOR GENETIC EVALUATION OF HOLSTEIN TYPE TRAITS, Journal of dairy science, 76(5), 1993, pp. 1421-1432
Animal model genetic evaluations for final score and 14 linear type tr
aits were implemented for US Holsteins in July 1991 and July 1992, res
pectively. Data included 5.19 million records on 2.83 million cows for
final score and 3.52 million records on 2.05 million cows for 14 line
ar traits. The model included effects of herd-year-month of classifica
tion, herd by sire interaction, permanent environment, and animal with
unknown-parent groups. A multiple-trait procedure for the linear trai
ts was facilitated by a canonical transformation in which the (co)vari
ance matrix for the herd by sire and permanent environment effects wer
e assumed to be proportional to that of the residual effect. Memory re
quirements were reduced by ordering the data by herds because over 87%
of the effects were nested within herds. Investigation of three diffe
rent computing platforms identified a Unix workstation as the best com
puting environment. Correlations between the sire and animal model bre
eding values for bulls with semen available in 1992 were .92 for final
score and .91 to .96 for the linear traits. Genetic merit of the mate
s was accounted for more completely by the animal model, resulting in
important differences in breeding value predictions between the two mo
dels.