Calculation and Use of Daughter Yield Deviations and Associated Reliabilities of Bulls Under Multiple Trait Models

A method was presented for calculating daughter yield deviations of bulls and average yield deviations of cows under general multiple trait models. Reliabilities associated with the yield deviations were approximated using the multiple trait effective daughter contribution method. The presented daughter yield deviation formula was verified to be correct in a simulation study with a random regression test day model and high accuracy of daughter yield deviations was also confirmed based on their correlations with proofs from a routine genetic evaluation using a random regression test day model. The daughter yield deviations and associated reliabilities can be used for international bull comparison based on a multiple trait multiple country model, marker assisted genetic evaluation and validation of national genetic evaluation system.