Association of genetic variants of bovine prolactin with milk production traits of Black-and-White and Jersey cattle

between polymorphism localised in the third exon of the prolactin gene (PRL-RsaI) and milk production traits of Black-and-White and Jersey cattle were analysed. A total of 427 cows were included in the study. PCR-RFLP method was used. The frequencies of genotypes and alleles were as follows: 0.7107 - AA, 0.2851 - AB, 0.0042 - BB; 0.8533 - PRL A and 0.1467 - PRL B for Black-and-White cattle and 0.0919 - AA, 0.4324 - AB, 0.4757 - BB; 0.3081 - PRL A and 0.6919 - PRL B for Jersey cattle. Statistically significant differences between the breeds were observed in the frequencies of genotypes and alleles. Associations between PRL-RsaI polymorphism and milk production traits of Jersey cows and lack of associations with these traits in Black-and- White cows were observed.