Effects of pre-weaning concentrate feeding on calf performance, carcass and meat quality of autumn-born bull calves weaned at 90 or 150 days of age.

A study was conducted to evaluate the effect of pre-weaning concentrate feeding in early-weaned (EW, day 90) or traditionally weaned (TW, day 150) autumn-born beef calves on growth, feed intake and feed efficiency, and carcass and meat quality. Twenty-eight male calves were either EW or TW, and offered a starter concentrate (S) or no additional feed (NS) during the pre-weaning period. Therefore, four management strategies were tested: EWS, EWNS, TWS and TWNS. Growth patterns were affected by management strategy. From day 90 to 150, TWNS calves presented a substantially lower average daily gain (ADG) than their counterparts, which had similar performance. During the finishing phase (from day 150 to slaughter at 450 kg live weight), EWS calves had the lowest ADG. Daily feed intake or efficiency in the finishing phase was unaffected by previous management. Serum IGF-I concentrations at day 90 and slaughter did not differ with management strategy, but early weaning and pre-weaning concentrate feeding increased IGF-I concentrations at day 150. Circulating leptin concentrations were unaffected by age at weaning and pre-weaning concentrate feeding, except for leptin concentrations at slaughter, which were higher in S calves than in NS calves. Total concentrate intake from birth to slaughter and the concomitant feed costs were higher for EWS and EWNS calves than for TWNS and TWS ones. However, cow feed costs were lower for cows whose calves had been early weaned. Concerning carcass quality, early weaning improved dressing percentage and increased fatness score, and particularly TWNS calves presented a poorer conformation. Meat quality was not affected by management strategy. Considering the economic performance, TWS, EWNS and EWS strategies yielded a similar economic margin, whereas TWNS would be the least advisable strategy when calves are fattened in the farm until slaughter.