Sire and Cow Evaluation Under Multiple Trait Models

Multiple trait analyses of dairy cattle data are becoming increasingly popular because they utilize more information to evaluate animals through genetic and environmental correlations, and they may account for particular types of bias caused by selection. Aspects of multiple trait analyses discussed include a) improvement of accuracy of evaluations from multiple trait analyses compared to single trait analyses; b) influence of correlations among genetic and residual elements on genetic evaluations for each trait; and c) effects of incorrect correlations on multiple trait analyses.