β-LACTOGLOBULIN GENE POLYMORPHISM IN HOLSTEIN-FRIESIAN CATTLE REARED IN BULGARIA: A POPULATION GENETIC PERSPECTIVE
β-lactoglobulin (LGB) is a major whey protein in ruminant milk. Its genetic polymorphism is of great interest due to its influence on the qualitative and technological properties of milk. The experiment was con-ducted within a small Holstein-Friesian population reared at the Academic Technological Complex of Trakia University – Stara Zagora and aims to determine the gene and genotype frequency distribution of the two major alleles of the β-lactoglobulin locus – A and B. The molecular analyses of the LGB gene were completed using the Axiom Bovine Genotyping Array v3. The observed frequencies were compared to the expected val-ues according to the Hardy-Weinberg principle. The results obtained demonstrate that the frequency of allele A is 0.73, while allele B has a frequency of 0.27. The performed χ² test revealed the studied population is in a state of genetic equilibrium (χ² = 0.0189332, df=1, P>0.05).