DOMINANCE OF ALLELES IN HETEROZYGOUS BETA -LACTOGLOBULIN GENOTYPES OFTHE CATTLE

4355 milk samples of 1991 Fleckvieh and 1453 Braunvieh cows were analy zed for beta-lactoglobulin content and yield to determine the expressi on of the beta-lactoglobulin alleles A and B in heterozygous and homoz ygous genotypes. Allel A significantly showed a stranger expression th an allele B in all cases, whereby the differences in heterozygotes wer e greater than in homozygotes. A genetic model of allelic effect was d efined which contains two dominance effects of heterozygous genotypes. Significant dominance effects of alleles had values of up to 10 %. An tagonistic signs of the dominance of the alleles led to relatively, sm all total dominance of the heterozygous genotypes. Seasonal dominance and dominance during the lactation period was estimated and continous positively dominance of the allele A and negatively dominance of the a llele B occured. It is presumed that the antagonistic dominance effect s of alleles of the beta-lactoglobulin locus is a general appearance.