Association of prolactin and beta-lactoglobulin genes with milk production traits and somatic cell count among Indian Frieswal (HF × Sahiwal) cows

Prolactin (PRL) and beta-lactoglobulin (BLG) are two important candidate genes well known to be associated with milk production traits as well as somatic cell count (SCC) among dairy cattle breeds. In the present study, the intron 3 of PRL and the spanning region between exon IV and intron IV of the BLG gene were chosen for genotyping and their association with milk production traits as well as SCC among HF crossbred cattle (i.e., Frieswal) that originated from India. We observed that the AA genotype frequency of PRL among Frieswal cows is higher than that of AB and BB. Our findings showed that cows with AA and BB genotypes had significantly (p < 0.05) higher total milk yield and peak yield than AB genotype cows. Comparing SCC with various genotypic groups, we observed that BB genotype cows had significantly (p < 0.05) lower SCC than those with AB and AA genotypes. In the case of BLG, the genotypic frequency of BB was higher than that of AB and AA. The AB and BB genotypes of BLG had a significant (p < 0.05) effect on total milk yield and peak yield compared with AA. The SCC of the AA genotype of BLG is significantly (p < 0.05) lower than that of AB and BB. This study thus indicates that AA and BB genotypes in PRL as well as AB and BB genotypes in BLG may be more suitable for better milk production; however, cows having BB genotype in PRL and AA genotype in BLG may show more resistance to mastitis than those with other genotypes among HF crossbred cattle.