[Quantitative differences between genetic variants of milk proteins in Cholmogor cattle].

The quantitative determination of genetical variants A and B of beta, kappa-caseins (beta-Cn, kappa-Cn), beta-lactoglobulin (beta-Lg) in Cholmogor cow's milk was carried out by means of polyacrylamide gel electrophoresis and direct densitometrication. In all milk proteins of heterozygous cows with beta-CnAB, kappa-CnAB, beta-LgAB the variant A content was higher than that of variant B (P less than 0.001). The variant A of beta-casein was 0.380 g/100 ml (54.6%), B-0.316 g/100 ml (45.4%); of kappa-casein A-0.208 g/100 ml (58.3%), B-0.149 g/100 ml (41.7%); of beta-lactoglobulin A-0.143 g/100 ml (54.8%), B-0.118 g/100 ml (45.2%). The alleles beta-CnA, kappa-CnA, beta-LgA ensure higher quantity of protein than beta-CnB, kappa-CnB, beta-LgB alleles.