Kappa-casein genotypic frequencies in Russian breeds Black and Red Pied cattle.

Casein is a family of milk proteins that exists in several molecular forms and is the main protein present in the bovine milk. The B variant of bovine k-casein is reported to be favorable for quality and quantity of cheese derived from milk and considered to be included in breeding strategies of dairy cattle. Genotypes of 72 Russian Black Pied and 80 Red Pied cows were determined for kappa casein locus by restriction fragment length polymorphism analysis (PCR-RFLP) of amplified DNA. A 530 bp. fragment of the genomic bovine kappa casein gene was amplified by PCR. Digests by Hind III thus genotypes AA, AB and BB, were recognized by agarose gel electrophoresis. This technique was used to determine the kappa casein allelic frequency in Black and Red Pied dairy herds. Estimated gene frequencies were 0.83, 0.69 for A, and 0.17, 0.31 for B alleles, for Black and Red Pied breeds, respectively. The heterozygosis of 0.28, 0.50 for Black and Red Pied breeds, respectively were observed. This molecular genetic technique based on molecular markers allows direct genotyping for milk Kappa casein with certainty and accuracy in bulls and females an can be used in programs of dairy cattle improvement. Therefore, an early and precise identification of milk protein genotypes should have a direct impact on dairy cattle breeding strategies.