Actavia 0 Hradecká, E. Čítek, J. Panicke, L. Řehout, V. Hanusová, L. 2008 2008-6-30 238-246 : We analysed the relations of estimated breeding values (EBV) of 315 German Holstein sires to their genotypes in growth hormone gene (GH1), growth hormone receptor gene (GHR) and acylCoA-diacylglycerol acyltransferase 1 (DGAT1). The strong relation of DGAT1 K232A to the estimated breeding values for milk production traits has been confirmed, when allele DGAT1^K was connected with higher milk fat yield, milk fat and milk protein content, while allele DGAT1^A increased milk yield and milk protein yield. The effect of DGAT1 genotype explained from 4.70% of variability of EBVs for fat yield to 31.90% of variability of EBVs for fat content. The evaluation of GH1 127 Leu/Val and GHR 257 SNP polymorphisms did not reveal an association of their polymorphism with EBVs for milk production traits, except the EBVs of GHR^G/GHR^G homozygotes for fat yield, which were significantly lower. The effect of GH1 or GHR genotype explained only a negligible portion of variability of EBVs (R² < 1.00% in most cases). 6 53