Identification of Polymorphism of the CSN2 Gene Encoding Beta-Casein in Ukrainian Black and White Breeds of Cattle

Genotyping of 606 animals of the Ukrainian Black-and-White dairy breed was carried out in order to establish the features of genotype formation by beta-casein. It is established that the modern population of this breed has been formed using stud bulls of the Holstein breed, mainly of the American and German breeding. It is found that the original breed has determined the features of polymorphism of the beta-casein gene.

According to the research results, it is proved that the existing genetic structure of stud bulls of the Holstein and Ukrainian Black-and-White dairy breeds enables formation of populations homozygous by these characteristics in subsequent generations.

Among the breeding stock of the Ukrainian Black-and-White dairy breed, the frequency of the desired A2A2 genotype was 33-53%. It is expected to increase the frequency of occurrence of individuals with the A2A2 genotype by beta-casein in subsequent generations, especially if stud bulls homozygous by A2A2 beta-casein is used.