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 with production traits. After exclusion of bulls carrying alleles that occurred at frequencies lower than 2% or whose production proofs were not available, records from 78 bulls remained for analysis. A gene substitution model, which included the effects of BoLA alleles and the breeding value of the sire of the bull as covariate, was used to evaluate the additive effects of BoLA alleles of bulls (ETAs) on the production traits of their daughters. Allele W17 was significantly associated with ETA for milk, fat and protein yields. Allele CA96 was associated with significant increases in ETA for fat yield. There was no significant association of BoLA alleles with either ETA for fat or protein percentage. Key words: BoLA, production traits, Ayrshire