The Impact of DGAT1 K232A Mutation on Milk Production and Quality Traits in Vechur and Crossbred Cattle of Kerala, India

Background: A dinucleotide substitution in exon 8 of the gene coding for acyl CoA: diacylglycerol acyltransferase 1 (DGAT1), which changes the amino acid sequence from lysine to alanine (p.Lys232Ala) in the mature protein, was found to have a significant effect on milk production and quality traits in certain cattle breeds. The present study was conducted on Vechur and Crossbred cattle of Kerala to evaluate the genetic diversity and effect of K232A polymorphism of diacylglycerol O-acyltransferase (DGAT1) gene on milk production and quality traits (305-day milk yield, peak yield, average daily yield, fat per cent and SNF per cent). Methods: A total of 60 Vechur and 180 crossbred cows were genotyped using High resolution melt (HRM) curve analysis. Association analysis was carried out using fixed general linear model (GLM) of SPSS V.26. Result: Monomorphic KK genotype was observed in Vechur cattle. The frequencies of genotypes for KK, KA and AA genotype were estimated as 0.55, 0.28 and 0.17 in crossbred cattle. The K allele was found to be fixed in Vechur cattle population. In the population under study, the allele K exhibited a higher prevalence compared to allele A, with a frequency of 0.69 as opposed to 0.31. The genotypes of K232A had significant (p≤0.01) effect on 305-day milk yield, peak yield, average daily yield and fat per cent in crossbred animals. The KK and KA genotypes showed significantly superior values for fat per cent (p≤0.01) compared to AA genotypes. The AA genotype showed significantly superior values for 305-day milk yield, peak yield and average daily yield compared to KK and KA genotypes. Hence, the findings of this study indicate that the DGAT1 gene exhibits significant potential as a candidate gene influencing both milk production and quality attributes in crossbred cattle of Kerala.