Influence of the polymorphism complex of cappa-casein (CSN3) and prolactin (PRL) genes on the milk productivity of the Holstein first calf heifers

The presented study is dedicated to the influence of the polymorphism complex of κ-casein (CSN3) and prolactin (PRL) genes, which are responsible for milk quality and milk productivity. The study was carried out among Holstein first calf heifers by Integrated Agricultural Production Centre “Breeding farm named after Lenin” of Atninsky district of the Republic of Tatarstan. DNA samples were separated from blood samples of 261 cows for identification and genotyping according to kappa-casein and prolactin genes by PCR-RFLP analysis method. When considering the gene polymorphism as whole cow-heifers with a complex CSN3AA - PRLAB genotype showed prominent results on milk yield (6648 kg), with a CSN3AA - PRLAA genotype - on percent fat content (3.84%), with a CSN3AB - PRLBB genotype - on percent protein (3.51%), with a CSN3BB - PRLAA genotype - on milk fat (265.2 kg), with a CSN3AA - PRLAB genotype - on milk protein content (210.6 kg). The study didn’t detect PRLBB - CSN3BB genotype complex.