Genotypes of milk protein genes, alpha S1 -casein (CSN1S1), beta-casein (CSN2), kappa-casein (CSN3) and beta-lactoglobulin (LGB), were detected in 440 individuals of Czech Fleckvieh breed using a PCR-RFLP method. Breeding values of genotyped animals were obtained from the Official Database of Progeny Testing. A granddaughter design including 5 grandsires, 33 sons and 402 granddaughters was used for evaluation. Statistical analysis was carried out in SAS program using a restricted maximum likelihood method (REML). The aim of this study was to determine allele and genotype frequencies of observed genes and to find the relation between genotypes of genes and milk production parameters expressed by the breeding values of animals. The positive findings of frequencies of CSN3 allele B (0.38) and genotype BB (13%) were detected in the observed population. Significant differences were found between genotypes of loci CSN1S1, CSN2 and CSN3 and breeding values for milk production parameters. Genotypes of LGB locus were not significantly related to any of the milk production parameters. Significant effects were found between CSN1S1 locus and average breeding value for milk yield, CSN2 locus and breeding values for all parameters except for protein content and CSN3 locus and breeding values for protein content and protein yield. These findings contribute to a better understanding of the genetic constitution of Czech Fleckvieh breed and help with the application of the information to breeding.

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