Kappe_Casein and Beta-Lactoglobulin Genotype Effects on Milk Production and Maternal Calf Growth Traits in Crossbred Beef Cattle

Cows were genotyped at the kappa-casein and beta-lactoglobulin loci and evaluated for milk yield, calf birth weight, weaning weight, and average daily gain from birth to 109 days and from birth to 21 1 days of age. The interaction of breed-group with genotype was significant for milk yield at both loci. Cow genotype and additive allelic effects were significant or approached significance for both measures of calf average daily gain and weaning weight at the kappa-casein locus. Cow genotype and additive allelic effects were significant for calf average daily gain to 109 days at the beta-lactoglobulin locus. Cow genotype approached significance for calf average daily gain to 21 1 days at the beta-lactoglobulin locus. The quadratic effect of number of A alleles in the cow's genotype (i.e., 0, 1, or 2) was significant or approached significance for several measures of calf growth, suggesting possible dominance effects.