ABSTRACT:The aim of the experiment was to compare the carcass composition of 20 Montbeliarde bulls (M) and 20 Czech Pied bulls (C). The carcass weight of the animals in one group varied minimally and was about 380 kg. The Montbeliarde bulls showed a higher growth rate, expressed by a significantly lower (P < 0.01) age at slaughter (562.6 vs. 626 days) while the live weight (682.9 vs. 690.6 kg) and carcass weight (380.4 vs. 382.6 kg) were comparable, which resulted in a significantly higher (P < 0.01) daily weight gain (1.142 vs. 1.045 kg) and net weight gain (0.676 vs. 0.615 kg). The Montbeliarde bulls showed a greater (P < 0.05) height at rump (144.0 vs. 140.2 cm), worse carcass conformation according to SEUROP (3.24 vs. 2.84), lower proportion of forequarter (44.7 vs. 45.7%) and higher proportion of hindquarter (55.3 vs. 54.3%). As for the carcass composition, no significant inter-breed differences were found in weights and proportions of shanks, meat trimmings, separable fat, bones, round, loin, filet, flank with rib, flank, shoulder and chuck. The Montbeliarde bulls had a significantly lower (P < 0.05) weight and proportion of neck (10.1 vs. 11.1 kg and 5.4 vs. 5.9%) and weight of brisket and rib (17.6 vs. 18.7 kg) and proportion of brisket and rib (9.4 vs. 9.9%, P < 0.01).

Czech Pied bulls (C, n=18) and Montbeliarde bulls (M, n=18) were fattened up to the live weight of 680 kg in identical conditions with the aim to compare their meat performance. Mean values of the observed meat performance characteristics were as follows: slaughter weight 682.1 kg, age at slaughter 593.8 days, daily weight gain 1.088 kg, carcass weight 378.2 kg, net weight gain 0.640 kg, dressing percentage 55.4%, weight of hide 59.3 kg, weight of head and tongue 20.6 kg, weight and proportion of kidney fat 14.9 kg and 2.18%, carcass conformation score 3.06, carcass fatness score 2.20 and weight of the right side of carcass 185.9 kg. The weight and proportion of some parts of the right side of carcass were as follows: forequarter 84.1 kg and 45.2%, hindquarter 101.8 kg and 54.8%, total weight of meat 145.5 kg and 78.2%, bones 35.0 kg and 18.9%, separable fat 3.87 kg and 2.08% and hindquarter to forequarter ratio 1.21. Montbeliarde bulls showed a significantly greater (POur results showed higher growth rate in Montbeliarde bulls; also, their further growth potential was higher than in Czech Pied bulls. The rest of the observed characteristics of meat performance, including carcass composition, were similar in both breeds and were not negatively affected by a high slaughter weight.

Blood samples were taken, in monthly intervals, for 12 months from Bohemian Spotted cows between 20 and 100 days post partum for total lipids, cholesterol, glucose and urea determination. In all, 208 cows were sampled to define the relation between reproductive performance and concentration of biochemical plasma indicators. Reproductive performance was characterized by the length of the interval (average 79.67 days), service period (average 113.64 days) and insemination index (average 1.67). Average values for the entire studied period were 5.33 mmol • 1~' for plasma urea, 3.16 g • 1 1 for total lipids, 3.93 mmol • 1~' for cholesterol and 3.93 mmol • l" 1 for glucose. During the investigations the length of the interval decreased from 111.39 days to 73.57 days and service period from 137.06 days to 84.61 days. The average concentrations of urea and total lipids changed in the individual months depending on changes in feed rations. Calculated correlations between the respective biochemical blood indicators and studied reproductive indicators changed in the same way. Indicators of reproductive performance were affected by the internal environment, particularly in the case of low lipaemia, and, in contrast, in the case of high blood plasma uremia.

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The effect of embryo donors and recipients of on milk efficiency of their female offsprings from embryo-transfer was followed. Heifers and cows of Czech Spotted Breed were used as a embryo donors and recipients. The selected characteristics of milk efficiency – the quantity of milk (kg), the quantity of proteins (kg) and content of proteins (%) were analysed by using of variation-statistical methods and analysis of variance (programme Statistica, version 6.0) by the donors (31), recipients (74) and their daughters (74) from embryotransfer. These selected characterictics were analysed in the 1st and in the maximal lactations. Milk efficiency of the recipients was the lowest in the 1st and maximal lactation; the recipients produced 4991.4 kg, and/or 6082.86 kg of milk and 174.79 kg, and/or 213.5 kg of protein; however, this differences were significant (P < 0.05 and P < 0.01). The protein content in % in milk of recipients was 3.45% in the 1st and maximal lactation; i. e. 0.05% more protein (insignificant difference), and/or 0.13% more protein than the donors (significant difference, P < 0.05). Milk efficiency was the highest in the offspring in the 1st and maximal lactation; the daughters from ET produced 938.5 kg, and/or 1804.7 kg of milk more (P < 0.01), 41.28 kg, and/or 67.32 kg of protein more (P < 0.01), and 0.14% (P < 0.01), and/or 0.11% (P < 0.01) of protein more than the recipients, and 305.48 kg, and/or 823.26 kg of milk more (P > 0.05), 0.19%, and/or 0.24% of protein more (P < 0.01) and 28.55 kg of protein more (P > 0.05) in the maximal lactation than the donors. In the 1st lactation the daughters from ET produced 2.58 kg less protein than the donors; however, this difference was insignificant (P > 0.05). There was found the effect of donors was significant on milk efficiency of their daughters and the effect of recipients was no significant on milk efficiency of their female offsprings from embryotransfer. There was found too that already the milk efficiency from first lactations could be using for selection of embryo donors.