Effects of polymorphisms in DGAT1 and LEP genes on milk traits in Holstein primiparous cows

Abstract

The genes encoding the diacylglycerol O-acyltransferase (DGAT1) and leptin (LEP) became a functional candidate genes for lactation traits in cows. Several studies associated single nucleotide polymorphisms (SNP) in these genes with fat and protein content in milk, fat and protein yield, milk yield and some reproductive traits. Three reported SNPs in these genes were investigated in our study (DGAT1-K232A, LEP-R25C, LEP-A80V). One hundred and sixty-three primiparous dairy cows from one farm were genotyped. The milk yield, fat and protein yield, fat and protein content and the age at first calving were recorded. The frequencies of alleles and genotypes were assessed. The effect of genotypes on milk traits and age at first calving were studied using linear models. The assumption of the different allele frequencies resulting from selection aimed at milk yield was proved in DGAT1 and LEP-A80V. The significant effect (P<0.01) of DGAT1 polymorphism was estimated only for the fat content. No significant effect of individual LEP polymorphism on milk trait or age at first calving was estimated. No significant effect of combination of LEP polymorphisms was estimated for those traits. The effect of DGAT1 on the age at first calving was indicated.

Keywords

• dairy cattle; milk production traits; polymorphism; leptin; diacylglycerol acyltransferase