Association of genetic variants of beta-lactoglobulin gene with milk production in a herd and a superior family of Holstein cattle

ABSTRACT

Polymorphism of the beta-lactoglobulin [beta-LG] gene in 101 cows belonging to the Holstein herd and a superior cow, producing more than 150 Kg milk/day, together with four offsprings was investigated by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism [PCR-RFLP] method. In the Holstein herd, the alleles A and B of the beta-LG gene had frequencies of 0.53 and 0.47, respectively. The genotypes AA, AB and BB of the beta-LG gene were estimated to have frequencies of 0.257, 0.544 and 0.198, respectively. Genotypes were distributed according to the Hardy-Weinberg equilibrium. Results indicated that the beta-LG genotypes significantly affected [P< 0.01] milk yield [genotype AA being more effective than genotype BB]. The superior cow and her progenies were all heterozygotes [AB]