Growth traits of purebred calves of six beef breeds (Aberdeen Angus – AA, Blonde d’Aquitaine – BA, Charolais – CH,Hereford – HE, Limousine – LI and Beef Simmental – BS) born from 1998 to 2002 were analysed. Traits under study were birth weight (BW), weight at 120 days (W120), weight at 210 days – weaning weight (WW), weight at 365 days – yearling weight (YW) and average daily gains from birth to 120 days (ADG1), from birth to 210 days (ADG2), from birth to 365 days (ADG3), from 120 to 210 days (ADG4). General linear model with class effects of breed, dam’s age at calving, sex, herd-year-season (HYS) and covariation of age at weighing was used for analyses. All effects significantly affected both weight and gain traits except for dam’s age that was significant for BW, W120, YW and ADG3, and age at weighing that was significant for W120, WW, YW, ADG2, ADG3, ADG4. Estimated least squares means of growth traits were compared using Scheffe’s multiple-range tests. Highest BW (40.57 kg) and W120 (172.43 kg) were found for BA calves. BS calves had highest WW (260.30 kg), YW (424.07 kg), ADG1 (1 154 g), ADG2 (1 053 g), ADG3 (1 054 g) and ADG4 (1 098 g). Highest BW, YW, ADG3 and ADG4 were found for males-singles. Males-twins had highest W120, WW, ADG1 and ADG2. Calves descending from 5–7 years old dams had highest BW, W120, WW, ADG1, ADG2 and ADG4. The proportion of variability of growth traits explained by HYS effect (42.96–71.69%) was high, whereas proportions of variability explained by SEX effect (2.03–5.77%), age of dam (1.02–2.24%) and breed (1.05–2.21%) were low. Residuals accounted for 23.71 up to 53.79% of total variance.  

No abstract

The aim of this study was to determine genotypes of four genetic markers and to investigate their association with milk production traits in Brown Swiss cattle imported to Slovakia. The bovine κ-casein, β-lactoglobulin, growth hormone and prolactin genotypes of 107 cows were identified by polymerase chain reaction. Effects all four genetic markers on milk, fat, protein and lactose yields and fat, protein and lactose percentage were estimated from a data set of 249 lactations. The frequency of desirable B allele of κcasein gene to milk production was 0.46, alleles A of β-lactoglobulin gene was 0.55, allele and L of growth hormone gene was 0.45 and allele A and B of bovine prolactin gene were 0.61 and 0.39. The results of milk production obtained in our work showed that BB genotypes of κ-CN gene, AA genotypes of β-LG gene, LL genotypes of bGH gene were significantly associated with better milk production traits, mainly about the fat content. Association of a bovine prolactin genotypes with milk production were not found.

Economic weights (EW) for the Slovak dairy production system were calculated in Holstein, Slovak Simmental, and Slovak Pinzgau breeds under a direct support regime using a bio-economic approach. EW were calculated for three scenarios (A: without agricultural subsidies; B: agricultural subsidies included in revenues and C: agricultural subsidies included in feeding costs). Quota-free milk production was assumed in all scenarios. The base price of milk was corrected according to real fat, protein and somatic cell content. Under the given economic and production conditions, only the Holstein system in scenario A was economically profitable. All simulated systems were profit-making when agricultural subsidies were taken into account (B and C). No influence of subsidies on EW of traits in scenario B was found. Most of the evaluated traits (especially milk and functional traits) showed higher marginal economic weights when subsidies were considered in feeding costs (C). Regardless of the scenarios, milk components were of higher relative economic importance for Holstein cattle than for Slovak Simmental and Slovak Pinzgau cattle. The relative EW of mature weight of cows and daily gain of calves mostly declined in scenario C. A meaningful effect of direct subsidy and milk production level on the economic efficiency of Slovak Simmental and Slovak Pinzgau cattle was found. Handling direct subsidy in scenario C seems to be suitable methodology to avoid the underestimation of EW for milk and functional traits.

SummaryThe aim of our studies was to determine, whether difference in GH alleles affect growth Performance in cows and whether these effects may be mediated by IGF-I. The presence of L (leucine-rich) and V (valine-rich) alleles of GH, plasma IGF-I level and changes in body mass were analyzed in 84 bulls of Simmental (meat) and Holstein (milk) breeds at 90 d and 180 d of age using PCR, agarose gel electrophoresis and IRMA The agedependent increase in body mass, daily gain and plasma IGF-I concentration was observed in Simmental bulls In Holstein bulls the age-dependent rise in plasma IGF-I was also found, whilst Holstein bulls had significantly lover IGF-I level, than Simmental bulls. The proportion of LL, VV and LV genotypes of GH in the randomly selected herd of Simmental bulls was 0.25:0.20:0.55. Animals of VV genotype had lower body mass, daily gain and plasma IGF-I level, than bulls of LL and LV genotypes, whilst no differences in these indexes between LL and LV genotypes were found.The observed association of growth rate, GH genotype and IGF-I level, suggest that GH genotype may affect meat Performance via IGF-I secretion.