Z. Veselá

Genetic diversity within and gene flow between three draught horse breeds using genealogical information

Three draught horse breeds are maintained in the Czech Republic: the Silesian Noriker (SN), the Noriker (N), and the Czech-Moravian Belgian (CMB). Because the SN and CMB populations are currently closed to outside breeding and are endangered (Genetic Resources), the loss of the genetic variation these horses represent is concerning. Genetic diversity within and between these three breeds and their population structures was analyzed based on pedigree information. Our goal was to identify and quantify factors that affected their genetic variability. The effective population size was analyzed in each breed. The numbers of generations were 22, 32, and 32 for the SN, N, and CMB breeds, respectively, with average equivalent known generations of 9.81, 8.45, and 8.91, respectively. The effective numbers of founders and ancestors contributing to the current genetic pool were, respectively, 69.42 and 22.32 for the SN breed, 98.48 and 42.20 for the N breed, and 43.33 and 23.32 for the CMB breed. The average inbreeding coefficients were 4.6%, 2%, and 4% for the SN, N, and CMB breeds, respectively, and the average inbreeding rate was 0.5% for the SN and CMB breeds and 0.2% for the N breed. The corresponding estimates of effective population size were 95, 195, and 101 for the SN, N, and CMB breeds, respectively. These statistics suggest that the genetic variability has decreased, and without changes in breeding strategy the genetic variability might continue to decline. Using genealogical F-statistics, small genetic differences were identified between the analyzed populations (FST = 0.02).

Genetic parameters of longevity for improving profitability of beef cattle

The objective of this study was to estimate genetic parameters for longevity and assess the suitability of using these selection criteria to improve the genetic merit of the beef cattle population of the Czech Republic. The performance record database, which contains records of 363,000 beef cattle animals of 19 breeds and their crosses, was used. The populations of Charolais and Aberdeen Angus were large enough that the genetic parameter estimations and all analyses were done for these breeds separately. Two similar approaches of longevity definition based on probabilities were considered as follows: productive longevity (PL), which is the number of calvings at target ages of 78, 90, 150, and 160 mo, and longevity (L), which is based on the probabilities of cow reappearance in the next parity. A multibreed single-trait animal model for L and a multitrait animal model for combinations of 78/150 and 90/160 mo for PL were used. Specific combinations of months were established based on the analysis and represented the critical culling rates in the studied population. The high genetic correlations (0.88-0.95) of the combination 90/160 suggested that the PL at 160 mo of age can be predicted on the basis of the value at 90 mo, which will make earlier selection possible. Combination 78/150 is less efficient in the Czech population of beef cattle due to the lower correlations (0.79-0.93) between traits. The estimated heritabilities were low for both traits (below 0.14), but the additive genetic variance was sufficient for identifying animals with high genetic merit.

Effect of the FGF2 SNP11646 on milk production and fertility traits of Holstein cattle

Th e objective of this study was to estimate the eff ect of a single-nucleotide polymorphism (SNP11646) in the FGF2 (Fibroblast Growth Factor 2) gene on the deregressed proof of breeding values (DRP) of Holstein sires (n = 149) for milk traits (milk yield, fat yield and percentage, and protein yield and percentage) and fertility (relative breeding value for own fertility – conception rate of heifers, cows, all females inseminated by the sperm of the sire; relative breeding value for conception rate of daughters – heifers, cows, all females). Th e diff erences between genotypes for milk performance were not signifi cant. Th e lowest DRP for milk performance were found for AA sires. For fertility, sires with this genotype had the best values both for the maternal genetic eff ect (conception rate of the daughters) and for the direct genetic eff ect (fertility of the sire). For conception rate of the daughters, in some cases, the diff erences reached the threshold of signifi cance. Th us, the results indicate coincidently with other studies the potential opposing eff ects on milk performance and fertility. FGF2 SNP11646 is still of interest for future cattle breeding studies.