An effect of the DGAT1 gene polymorphism on breeding value of Polish Holstein-Friesian sires

The effect of the GC→AA polymorphism in the DGAT1 gene causing amino acid substitution (lysine – K to alanine – A) was estimated on the breeding value (BV) of 89 Polish Holstein-Friesian sires. A fragment of 411 bp of the DGAT1 gene was analysed by RFLP (Cfr1) or MSSCP (screening for other substitutions). Only GC→AA in exon 8 dinucleotide substitution was identified causing K232A amino acid substitution. The frequencies of K and A alleles were 0.54 and 0.46, respectively. The KK genotype (compared to AA and KA) was found associated with higher BV for fat and protein content of milk and lower BV for milk and protein yields. Distribution of the polymorphism within the Holstein-Friesian population, as well as its effect on bull BV are discussed.