Genetic variants of kappa-casein gene in Busha and Brown Swiss breeds of cattle

The genetic variants of kappa-casein gene were found in different frequencies in various cattle breeds. These genetic variants cause differences in quality and composition of the milk. The objective of this work was to identify the genotypes and allelic frequencies of kappa-casein locus in Brown Swiss as an exotic breed and Busha cattle as indigenous cattle breed in Montenegro. The DNA of 21 blood samples of Busha breed cattle and 19 blood samples of Brown Swiss cattle were genotyped for polymorphisms at the kappa-casein gene by a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) essay. A 351 bp fragment of kappa casein was amplified and digested with HinfI restriction endonuclease. Three genotypes were identified (AA, AB and BB) with frequencies of 0.117, 0.450 and 0.433 respectively in Brown Swiss breed and 0.274, 0.499 and 0.227 in Busha breed. The frequencies of alleles were 0.316 (A) and 0.684 (B) in Brown Swiss and 0.524 and 0.476 (respectively) in Busha cattle. The genotyping of kappa-casein alleles (A and B) is of practical importance, since B allele is in positive correlations with commercially valuable parameters of cheese yielding efficiency. The results of very high frequency of B allele in Brown Swiss cattle confirmed good performance of this breed in Montenegrin population. This determination of A and B allele frequencies in population of Busha breed is the first research of this kind in Montenegro. It could be used for possible increasing the frequency of desired alleles and genotypes by including in the programs of selection and preservation of the Busha breed in Montenegro, as an important animal genetic resource.