Fattening performance of crossbred (Polish Holstein-Friesian × Hereford, Limousin or Charolais) bulls and steers offered high- wilted grass silage-based rations

7 CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 76(1) JANUARY-MARCH 2016 3 ULY-SEPTEMBER In Poland beef cattle are usually fed high-wilted grass silage offered ad libitum and supplemented with concentrate, whereas ‘Limousin’, ‘Charolais’ and ‘Hereford’ bulls are the most frequently crossed with dairy cows to produce beef hybrids. The aim of this study was to determine the fattening performance of hybrids produced by crossing ‘Polish Holstein-Friesian’ (PHF) cows with ‘Hereford’ (HH), ‘Limousin’ (LM) and ‘Charolais’ (CH) bulls, fed silage made from high-wilted grass and supplemented with a small amount of concentrate, depending on sire breed and category. The experimental materials comprised 24 bulls and 24 steers, including 8 PHF × HH, 8 PHF × LM and 8 PHF × CH crosses with initial body weight of approximately 300 kg in each group. The animals were fed grass silage with a DM content of 417 g kg-1, supplemented with concentrate at 35 g DM kg-1 W0.75, for 250 d. Steers were characterized by higher total DM intake per unit of metabolic body weight (P < 0.05): 92.8 vs. 87.0 g; 94.1 vs. 84.6 g; 88.6 vs. 87.0 g (PHF × HH; PHF × LM; PHF × CH, respectively) and bulls – by higher average carcass weight gains (P < 0.01): 700 vs. 631 g; 654 vs. 579 g; 633 vs. 574 g and carcass dressing percentage (P < 0.01): 60.0 vs. 56.4%; 60.2 vs. 58.9%; 60.2 vs. 56.6% (PHF × HH; PHF × LM; PHF × CH, respectively) and better (P < 0.01) silage DM, total DM, crude protein, and net energy utilization. Sire breed had no significant effect on the analyzed parameters of fattening performance but numerically PHF × HH crosses had the highest productivity parameters.