Influence of the bovine acyl-CoA:diacylglycerol acyltransferase 1(DGAT1)K232A genetic variation on somatic cell score and milk performance
The study aimed at estimating the association between of the DGAT1 K232A whit somatic cell score (SCS)and milk performance Holstein cattle.The gene diacylglycerol-O-transferase1(DGAT1)is mapped to the centromeric end of The bovin BTA14 and encodes the acylCoA:diacylglycerol acyltransferase 1enzyme which catalyses the final step in triglyceridesynthesis . K232A polymorphism proved to significantly affect the percent fat content in milk.Genotyping population, was performed using RFLP-PCR technique. A 411 bp fragmentincluding was amplified and digested with the enzyme CfrI to determine the genotypes of408 Holstein cows. Three types genotype KK, KA and AA were detected. Frequency of K andA allels were estimated 0.37 and 0.63, respectively. The statistical analyses showed positive andsignificant effects of the genotype for milk production and fat percent traits in first lactations buthaven’t significant effect for scs. Estimated average effects of substituting the lysine allele forthe alanine variant on record milk production, fat percent, protein percent and somatic cell scoreof milk -155.56, -1.5, 0.1978, 0.0452 and -0.0848 respectively. These results can be showed thatallele K is effect on increase fat of milk and decrease milk production. Also allele A is effect onincrease milk production and decrease fat milk. The relatively lower frequency of the K allelethan the A allele may be due to selection for milk yield in recent years. Results showed that theDGAT1 K232A polymorphism can be a source that underlies the reported quantitative trait locifor fat content trait in the proximal region of bovine chromosome 14.