Effect of slaughter age on performance of fattening calves

Twenty four Holstein x Zebu calves of two days I of age were used in a comp letely randomized design and distributed according to the following slaught er ages: A) 90 days; B) 180 days; C) 270 days and D) 360 days. All calves r eceived 5 litres of colostrum from 3 to 7 days and 5 litres of milk: from 8 to 20 days. From 21 to 30 lays, 4 litres of milk + 100 g of milk replacers (RELAC) were supplied and from 31 to 90 days, 2. litres of milk + 1000 g o f RELAC + 4 litres of warm water were fed. nle liquid feeds were offered tw ice a day. From 21 days until slaughter, an integral diet and water ad libi tum was supplied. Liveweight at 90, 180, 270 and 360 days did not differ be tween treatments. Carcass yield with respect to liveweight were 50.0, 545, 55.8 and 56.5%, which increased with slaughter age (P < 0.001). The proport ion of first quality meat did not differ, while second quality meat and rem ovable fat were increased (P < 0.001) with age. Bone proportion decreased(P < 0.001) with age. It is concluded that calf fattening with this managemen t and feeding system, is possible allowing slaughter ages of between 270 an d 360 days with advantages in carcass yield, edible meat and general perfor mance.