Abstract
OBJECTIVE: The objective of this research was to discover single-nucleotide variations in the -prolactin (PRL) gene and to evaluate their correlation with milk production characteristics in Ayrshire cows reared in southern Russia. MATERIALS AND METHODS: DNA (deoxyribonucleic acid)samples were extracted from the blood of cows (n = 300) using a commercial kit. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was employed to identify and quantify genotypes and allele frequencies. Genetic indices were calculated, and statistical processing was performed. A general linear model was used to investigate the relationship between single-nucleotide polymorphisms and milk productivity in cows. RESULTS: The distribution of the AA, AB, and BB genotypes in the studied population was 90%, 0%, and 10%, respectively. The genetic equilibrium in the Ayrshire cow population was preserved (χ² = 0.2879). The results indicate the presence of allelic diversity in the prolactin gene in this -population. The milk yield per lactation in cows with the PRL_AA genotype was 7,378.50 kg, and for PRL_BB, it was 6,569.63 kg. Ayrshire cows with the PRL_BB genotype yielded less milk compared to their PRL_AA counterparts by 10.96% (p < 0.05). CONCLUSION: Using the obtained results in the future selection of offspring with desirable PRL -genotypes at an earlier age could significantly increase the efficiency of breeding work in the studpulation and accelerate the process of creating a herd with higher productivity potential.