polymorphism of the b-lactoglobulin (b-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 b-lg gene had frequencies of 0.53 and 0.47, respectively. th...