Associations between Leu/Val polymorphism of growth hormone gene and milk production traits in Black-and-White cattle

Abstract. Associations between polymorphism of the bovine growth hormone (GH) gene (Leu/Val) and milk production traits of Black-and-White cattle with different proportional share of Holstein Friesian genes were analysed. A total of 1086 cows were included in the study. PCR-RFLP method was used for genotyping. The frequencies of genotypes and alleles were as follows: 0.653 for LL genotype, 0.324 for LV and 0.023 for VV, and 0.815 for GH^L and 0.185 for GH^V. Associations between Leu/Val polymorphism and milk production traits of cows were found only in first lactation. Cows with LL genotype had higher milk, fat and protein yield compared to LV individuals (P ≤ 0.01).