ASSOCIATIONS OF DGAT1 POLYMORPHISM WITH MILK CHARACTERISTICS IN SLOVAK DAIRY COWS

Abstract

DGAT1 encodes diacylglycerol O-acyltransferase (EC 2.3.1.20), a microsomal enzyme that catalyzes the final step of triglyceride synthesis. It was shown that the QTL variation is most likely caused by a nonconservative base substitution in the candidate gene DGAT1 changing lysine to alanine (K232A) in the enzyme diacylglycerol O-acyltransferase (DGAT). In particular, the allele encoding the lysine 232 variant proved to be more efficient with regard to milk fat synthesis. The objective of the present study was to determine the allele frequencies and to verify the effects of the two DGAT variants (K232A polymorphism, A and K alleles) on milk production traits in Slovak dairy cows.
Samples of 196 dairy cows originating from 61 sires were genotyped for DGAT1 K232A polymorphism (A and K alleles) using the PCR-RFLP technique. The frequencies of DGAT1 alleles were 0.88 (A) and 0.12 (K). The performance data were collected during one season in order to minimize this effect. The overall milk yield (MILK), fat yield (FAT_Y), fat content (FAT_C), protein yield (PROT_Y), protein content (PROT_C) and age at first calving (AGE1) were studied. The effect of DGAT1 polymorphism on fat and protein content in milk was confirmed. Further study is needed for explanation of effect of DGAT1 on the age at first calving.