Polymorphism of SNP g.8398A>G at prolactin gene and its effect on Indonesian Holstein dairy cow's milk performance and reproductive traits

The objective of this study was to identify the polymorphism of Single Nucleotide Polymorphism (SNP) g.8398A>G at the prolactin gene exon 4 in Indonesian Holstein dairy cows and its effect on milk production, milk quality, and reproductive traits. A total of 140 blood samples were investigated to detect polymorphism by PCR-RFLP method using the RsaI restriction enzyme. Sequencing was per-formed for confirmation of SNP mutation points. The phenotype data collected were milk production, milk quality, and reproductive traits. Data were analyzed using a t-test. The results showed that poly-morphism of SNP g.8398A>G at prolactin gene exon 4 was found in the study populations with AG and GG genotypes. Cows with the GG genotype indicated higher total milk yield and milk protein (P<0.05) than the AG genotype. Polymorphism was not associated with specific gravity, milk fat, milk lactose, total solid non-fat, and reproductive traits. SNP g.8398A>G at prolactin gene exon 4 showed potential as a genetic marker for selecting superior milk production traits.