MILK PROTEIN POLYMORPHISM IN AUSTRIAN DAIRY-CATTLE BREEDS

Individual milk samples from 4527 cows of the following dairy cattle b reeds in Austria were analyzed for phenotypes of genetic milk protein variants by isoelectric focusing: Simmental cattle (SI), Brown cattle (BR), Tyrolean Grey (TG), Pinzgau cattle (Pl), Holstein Friesian (HF) and Jersey (JE). Between breeds there were found great differences in occurence and frequency of the genetic variants of alpha(s1)-casein (A , B, C), beta-casein (A(1), A(2), A(3), B, C), kappa-casein (A, B, C, E) and beta-lactoglobulin (A, B, D). Allele frequencies of desirable c asein variants differed considerably between the breeds. alpha(s1)-Cn C decreased in the following order: JE (0.337), PI (0.252), TG (0.208) , SI (0.122), BR (0.067) and HF (0.032). Allele frequencies of beta-Cn B were as follows: JE (0.246), TG (0.218), BR (0.164), SI (0.083), PI (0.040) and HF (0.024). The frequencies of kappa-Cn B decreased in th e following order: JE (0.658), BR (0.592), TG (0.452), SI (0.286), PI (0.240) and HF (0.092). The most prevalent genotype combinations for t he alpha(s1)-Cn, beta-Cn and kappa-Cn loci occurring in the Austrian d airy cattle populations were as follows: SI (BB/A(2)A(2)/AA 15.0%), BR (BB/A(2)A(2)/BB 22.1%), PI (BC/A(1)A(2)/AA 12.5%), TG. (BB/A(2)A(2)/A A 10.7%), HF(BB/ A(1)A(2)/AA 34.8%), JE (BC/A(2)A(2)/AB 21.7%). In com parison with the results of a 1975 investigation in Austria, a signifi cant (p < 0.05) decrease in the allele frequency of kappa-Cn B has tak en place in Simmental cows (from 0.412 to 0.286).