A comparison of finishing strategies to fixed slaughter weights for Holstein Friesian and Belgian Blue × Holstein Friesian steers

Cattle finishing strategies may involve feeding a high energy diet throughout or following\na period of moderate growth. The objective of this study was to compare Holstein\nFriesian (HF) and Belgian Blue × Holstein Friesian (BB) steers (24 per breed type,\ninitial live weight 434 and 431 kg for HF and BB, respectively) finished to 560 kg or 620\nkg target slaughter weight, on either a concentrate diet ad libitum from the start of the\nfinishing period (C), or on a concentrate diet ad libitum following an 84-day period on\ngrass silage (SC). Slaughter weights were similar for HF and BB, but kill-out proportion,\ncarcass weight and carcass conformation class were superior (P < 0.001), and\ncarcass fat score was inferior (P < 0.001), for BB. Total concentrate, dry matter and net\nenergy intakes were higher (P < 0.001) for HF, and efficiency of utilization of net energy\nfor carcass-weight gain was lower (P < 0.01). Mean daily live-weight gain was higher\nfor C than SC (P < 0.001) and for slaughter at 560 kg than at 620 kg (P < 0.05). Killout\nproportion was higher for C than SC (P < 0.05) and for 620 kg compared to 560 kg\nslaughter weight (P < 0.001). Measures of fatness were unaffected by feeding treatment\nbut all were higher (P < 0.01) for the 620 kg slaughter weight. Net energy required\nper unit carcass-weight gain was higher for C than SC (P < 0.001) and for 620 kg\nthan for 560 kg slaughter weight (P < 0.001). When slaughtered at 620 kg live weight\nthere was no difference between the feeding treatments in net energy required per unit\ncarcass-weight gain. While both breed types had similar live-weight gain BB had 9%\ngreater (P < 0.01) carcass-weight gain and were 14% more efficient (P < 0.01) in converting\nfeed energy to carcass weight. Neither breed type had commercially acceptable\ncarcasses at 560 kg slaughter weight when finished on SC.