Performance and carcass quality of Czech Fleckvieh, Charolais and Charolais x Czech Fleckvieh bulls fed diets based on different types of silages

A total of thirty-four Czech Fleckvieh (CF), Charolais (CH) and CH x CF bulls with an average weight of 284 kg were included in the experiment and fed ad libitum two mixed diets as follows: MS (based on maize silage) and LCS (based on legume-cereal and lucerne silages) with different concentrations of dietary energy until slaughter at the target live weight of 600 kg. The CF bulls consumed more dry matter (DM) of feed daily than the CH bulls (P less than 0.05) and gained weight less efficiently than the CH x CF and CH animals (P less than 0.01) during the entire experiment. The killing-out percentage was lower in the CF than in the CH x CF and CH bulls (P less than 0.05). The CH bulls received a higher score for carcass conformation and a lower score for carcass fatness (P less than 0.01) than the CF bulls, had lower proportions of kidney and liver fat (P less than 0.01) than the CH x CF and CF bulls, and produced the highest percentage of high-priced meat (P less than 0.05) and the lowest percentage of separable fat (P less than 0.001). The bulls on the MS diet were younger than the others at the end of the experiment (P less than 0.01), gained weight more rapidly (P less than 0.001), consumed less DM (P less than 0.001) daily, utilized nutrients more efficiently over the entire experimental period (P less than 0.001), and had a higher proportion of internal fat than the LCS bulls. It can be concluded that purebred CH bulls were superior to the other breed groups in most of the traits observed. The intensive diet based on maize silage increased average daily gains, reduced the time needed to achieve the target slaughter weight, and improved the feed efficiency of bulls.