association of prolactin gene variants with milk production traits in russian red pied cattle

a total of 125 russian red pied cows were genotyped for the prolactim-related gene. the prl-rsai genotypes were analysed using the polymerase chain reaction -restriction fragment length polymorphism (pcr-rflp) method. in this breed, the frequencies of alleles were as follows;  a= 0.794 and b= 0.206. the frequencies of aa, ab and bb genotypes were 0.598, 0.392 and 0.01; respectively. results showed that: bb genotype had higher milk yield than aa and ab individuals (p< 0.05). bb genotype showed higher milk fat yield than aa and ab individuals (p< 0.05). with respect to milk fat content (%), the ab genotype had higher levels than the aa and bb individuals (p< 0.05). no differences between the cows of different prl-rsai genotypes were found in terms of milk yield and milk protein concentration. the results showed that the highest milk and milk fat yields were obtained by cows with the genotype prl-rsai bb. the results presented here demonstrate that the prolactin gene may be considered as a marker for dairy traits in cattle.