The effects of FASN and DGAT1 gene polymorphism on colostrum and milk fatty acid composition of Charolais cows and growth in Charolais calves

Fatty acid composition of milk has become an important trait in dairy production, but there has not been a large amount of research on milk fat composition in beef cows. The aim of this study was to evaluate the effects of polymorphisms in the fatty acid synthase (FASN) and acyl-CoA diacylglycerol acyltransferase (DGAT1) gene on milk and colostrum fatty acid composition, and their direct (calf) and indirect (cow/mother) relationships with calf birth weight and weight gain over 14 days. Eight Charolais cows and eight calves were genotyped using the PCR-RFLP method. The cows' milk and colostrum fatty acid profiles and their calves' weight at birth and 14 day weight gain were analysed. In the colostrum, cows with DGAT1 genotype KA had a significantly higher content of C4:0 and lower C10:0, and with FASN diplotype TW/AR a tendency for higher C14:0 and C16:0 colostrum FA content. In the milk, Charolais cows with diplotype TW/AR tended to have higher C14:1, C16:0 and C16:1, but lower C18:0 content. At the same time, no associations were found between DGAT1 genotypes and the fatty acid composition of milk. There were also no significant associations found between the studied SNPs and the calf's birth weight and weight gain over 14 days, although calves with DGAT1 KA genotype tended to have higher birth weight.