ASSOCIATION OF CLASS-I BOVINE LYMPHOCYTE ANTIGENS WITH PRODUCTION TRAITS IN THE AYRSHIRE BREED

Ninety progeny tested Canadian Ayrshire bulls were serologically typed for the BoLA-A locus to determine the association of these alleles wi th production traits. After exclusion of bulls carrying alleles that o ccurred at frequencies lower than 2% or whose production proofs were n ot available, records from 78 bulls remained for analysis. A gene subs titution model, which included the effects of BoLA alleles and the bre eding value of the sire of the bull as covariate, was used to evaluate the additive effects of BoLA alleles of bulls (ETAs) on the productio n traits of their daughters. Allele W17 was significantly associated w ith ETA for milk, fat and protein yields. Allele CA96 was associated w ith significant increases in ETA for fat yield. There was no significa nt association of BoLA alleles with either ETA for fat or protein perc entage.