The aim of the study was to analyse the association of ACACA and SCD1 polymorphism with milk composition, fatty acid profile in milk fat and milking performance of Polish Holstein-Friesian cows. The animals were divided according to criteria: lactation – 1st, 2nd, 3rd, 4th; ACACA polymorphism – CC, CG, GG; SCD1 polymorphism – AA, VA, VV. The presence of A293V polymorphism of SCD1 gene in the population of Polish Holstein-Friesian cattle has been confirmed. In the analysed fragment of ACACA gene presence of a novel SNP has been revealed. The SNP AJ312201.1g.1488C>G consists of a substitution G>C in 1488 position. This ACACA polymorphism influenced C13:0, C14:1, C16:1 and CLA, while the analysed SCD1 polymorphism influenced C14:1. Interestingly, C16:0, C18:0 and C14:1 were influenced by fat content; while C16:1 was influenced by lactation stage; and CLA was influenced by both lactation stage and fat content. Although the novel SNP on ACACA gene and A293V on SCD1 showed only slight influence on fatty acid profile in this study, these genes are still potential candidate genes for fat content and composition in milk, but require further research.
