ABSTRACT:The aim of this study was to estimate allelic and genotypic frequencies of five DNA markers that are positional and functional candidates for milk production traits in Czech Fleckvieh cattle. In addition, we evaluated the association of these markers with milk production traits and breeding values for milk production traits and also estimated linkage disequilibrium (LD) between two markers within the prolactin (PRL) gene. As part of this study, 505 Czech Fleckvieh cows were genotyped. The markers in proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A), secreted phosphoprotein (SPP1), cytochrome P450 family 11 subfamily B hydroxylase (CYP11B1), and the two polymorphisms in the prolactin gene (PRL) showed evidence of segregation in our study. The PPARGC1A polymorphism was associated with milk yield, milk fat and protein traits. The polymorphism in SPP1 was significantly associated with milk protein percentage. The CYP11B1 polymorphism showed positive associations with milk composition traits and breeding values for milk yield, milk fat, and protein traits. Both polymorphisms within the PRL gene were associated with milk yield, milk fat and milk protein yield (individually and grouped). Linkage disequilibrium between the two polymorphisms in PRL was not observed. In conclusion, all markers examined in this study are important markers for milk production traits in Czech Fleckvieh cattle, and both markers within the PRL gene should be evaluated in future research.

ABSTRACT:The phenotypic relationships between type traits and functional traits were analyzed in 47 786 Czech Fleckvieh cows first calved from 1994 to 2003. Functional survival was defined as the number of days from first calving to culling. All the cows were scored for conformation during the first lactation. Type information consisted of phenotypic type scores for 17 objectively scored linear type traits (with 9 classes each) and of the measurements for 6 body traits (measured in cm). The impact of the chosen conformation traits on functional longevity was estimated using the Cox proportional hazards model. The statistical model included the combined time-dependent effects of lactation and stage of lactation, age of the first calving, effects of the herd of culling, effects of year-season of culling, effects of the first lactation milk yield calculated within herd-year deviation. Analysis was performed separately for each of 23 type traits. The relative culling risk was calculated for animals in each class after taking into account the previously mentioned effects. All the traits analysed showed a relationship with the functional survival. Among linear type traits, rump angle, body depth, rear legs side view and pastern, fore udder length, rear udder attachment, and teats traits exhibited an intermediate optimum. Height at the sacrum, muscularity, rump length, and rump width, hock, and hoof angle, central ligament, and udder depth tended toward a linear relationship to functional survival. Body measurement traits showed an almost linear relationship concerning longevity except for chest girth, which exhibited an intermediate optimum. Body measurement traits and body conformation traits had an impact on functional survival especially in extreme classes, e.g. extremely ascending rump. Larger, broader, muscular cows had a higher risk of being culled compared with smaller and narrower cows and, hence, a shorter length of productive live. Foot and leg traits had an important influence on functional longevity, especially rear legs side view and pastern. Among udder traits, fore udder length, rear udder attachment, and front teat placement showed a higher impact on cows' longevity than the other analyzed udder traits.

ABSTRACT:The aim of this study was to determine the joint effects of CSN3 and LGB genotypes on parameters of production, quality and coagulation of milk in Czech Fleckvieh cows. Three hundred and twenty-eight Czech Fleckvieh cows were determined for CSN3 (kappa-casein) and LGB (beta-lactoglobulin) genotypes using the PCR-RFLP method, milk quality parameters and coagulation properties. Milk production parameters were obtained from the Official Database of Progeny Testing. Fifteen genotype combinations were detected, with ABAB (21.0%) and AAAB (18.3%) occurring as the most frequent. The observed genes significantly affected the contents of milk protein (crude protein, true protein, casein and whey protein) as well as solid non-fat in milk, casein number and curd quality. BBAA was found to be the genotype with the highest positive impact on most of the milk characteristics evaluated. Whereas ABBB, BBBB, BBAB and ABAB had a positive influence on milk quality and milk coagulation properties, genotypes containing CSN3 allele E had a negative effect. Results presented in this study are applicable in the selection of Czech Fleckvieh cattle.

Our findings indicate that the yoghurt fermentation test together with MP genotyping could contribute to milk quality control and highlight new perspectives in dairy cattle breeding based on selecting the best animals as parents of the next generation.

ABSTRACT:The objective of this study was to estimate the joint effects of CSN3 and LGB genotypes on breeding values of milk production parameters. CSN3 (kappa-casein) and LGB (beta-lactoglobulin) genotypes of 120 Czech Fleckvieh sires were detected using the PCR-RFLP method. Breeding values of sires were obtained from the Official Database of Progeny Testing. Ten genotype combinations were detected. Genotypes ABAB (25.0%), ABAA (13.3%) and ABBB (13.3%) were the most frequent. Significant effects of genotype combinations on breeding values for fat and protein content were found. The highest breeding values for milk (+621 kg) and protein (+15.8 kg) yields were associated with genotype combination ABAA, while the highest breeding values for content parameters (+0.15% for protein content and +0.55% for fat content) were associated with genotype combination BBAB.