Comparison of beef yield in young bulls of Slovakian Pied breed after various sires

The objective of the paper was to determine beef yield in the progeny after selected breeding bulls of simmentalized breeds of domestic and foreign pr ovenance. The trial was a long-term one, lasting from 150 to ca. 480 days o f age. Average daily live weight gains ranged from 1,172 g and 1,193 g in g roups D and E to 1,342 g and 1,363 g in groups C and F by about 480 days of age, and from 1,310 g and 1,325 g to 1,458 and 1,454 g in the same groups by one year of age. Average growth rate in groups A and B was at the middle level between the above pairs of groups. Groups A to E include progenies a fter different sires. Similar results of the group position were determined for net weight gains. There were no larger differences in nutrient consump tion per feeding day between the groups, and nutrient consumption per unit of production was determined by the growth rate. The weight of dressed carc ass was influenced by pre-slaughter weight, and the differences in dressing percentage were insignificant. Internal fat deposition was low, even at hi gher live weights and higher growth rate, kidney fat content ranged from 0. 97 to 1.40% in the separate groups while total internal fat content was bet ween 2.09 and 2.79% of pre-slaughter live weight. Very good parameters of b eef yield were established in some breeding bulls during the trial; breedin g value for milk yield was relatively high. With regard to the breeding pro cess of simmentalized breeds, it is necessary to make strict tests of meat yield inheritance. The highest parameters of beef yield and breeding bull p rogeny in the trial were determined at the breeding value for milk producti on ca. 8,500 kg.