Effect of weaning age and milk feeding level on pre- and post-weaning growth performance of Sahiwal calves

摘要

The Sahiwal cow is a tropical dairy breed native to Pakistan. The objective of the present study was to evaluate pre- and post-weaning growth of Sahiwal calves weaned either at 8 or 12 weeks and offered milk at either 10% or 15% of bodyweight (BW) from birth to weaning. Colostrum fed Sahiwal calves (n = 48) were randomly allocated to four treatments of 12 calves each. Calves were offered milk either at 10% (low-milk) or 15% (high-milk) of BW in two weaning programs (early or late). Early weaned calves were offered milk until Day 35, adjusted weekly for liveweight and then reduced by one-third in each subsequent week until weaned at Day 56 (early weaned). Late-weaned calves were offered milk until Day 63 and were weaned at Day 84 (late-weaned) by reducing milk offered by one-third in each subsequent week. Calves were offered a concentrate ration (21% crude protein and 2.93 metabolisable energy, Mcal/kg) from Day 28 to Day 112. Final BW at 16 weeks was highest (77.6 +/- 1.8 kg; P & 0.01) in high milk-fed late-weaned calves and lowest in low milk-fed early weaned calves (60.2 +/- 1.8 kg). High-milk early weaned and low milk late-weaned calves had comparable final BW (70.7 +/- 1.8 vs 72.0 +/- 1.8 kg), although lower than that of high-milk lateweaned calves, but still at an acceptable lower feeding cost to gain per kg liveweight (US$ 3.2 vs 2.5). Thus, offering milk to Sahiwal calves at 15% of BW and weaning at 8 weeks saves milk and labour required for additional days to feed these calves.