Escrivão R J A, Webb E C, Garcês A P J T
Department of Animal Production, Faculty of Veterinary, Eduardo Mondlane University, Maputo, Mozambique.
Trop Anim Health Prod. 2009 Jan;41(1):135-9. doi: 10.1007/s11250-008-9168-8. Epub 2008 Apr 26.
Fifty-two multiparous Brahman type cows with reproductive tract scoring (RTS) >/=4 at 45 days post-partum were randomly assigned to two groups of 26 cows each separated into an ad libitum suckling group (C) and treatment group (T). Calves in the T group were separated for 12 h during the night from 45 days post-partum to the onset of the breeding season. Body condition score (BCS) and body weight (BW) were recorded 45 days post-partum, at the start of the breeding season, and at pregnancy diagnosis. Calves were weighed at calving and weaning. Weaning weights were corrected to 205 days. BW and BCS at the onset of the breeding season were similar (p > 0.05) between the experimental groups. Calving to breeding intervals were 93 +/- 18 d and 99 +/- 22 d for T and C groups, respectively. Calving to conception intervals differed significantly between the groups (111 +/- 10 d for T and 133 +/- 19 d for C) and a similar result was obtained for the breeding to conception intervals (18 +/- 15 d for T and 31 +/- 19 d for C). Conception rates were 80% for the T group and 59% for the C group, which correlated better with BW than BCS at the onset of the breeding season. Weaning weights differed (p < 0.05) between C and T groups. From 45 days post-partum to the onset of the breeding season, cows in the T group experienced a positive energy balance (3%) while those in the C group had a negative energy balance (-0.1%). It was concluded that 12 h calf separation at night increases the conception rates and improves the calf weaning weights of Bos indicus beef cattle under extensive production systems in sub-tropical conditions.
52头经产婆罗门型母牛在产后45天生殖 tract 评分（RTS）≥4，被随机分为两组，每组26头，分别为自由哺乳组（C组）和处理组（T组）。T组的犊牛从产后45天至繁殖季节开始期间，夜间分开12小时。在产后45天、繁殖季节开始时以及妊娠诊断时记录体况评分（BCS）和体重（BW）。犊牛在出生和断奶时称重。断奶体重校正至205天。两组在繁殖季节开始时的BW和BCS相似（p>0.05）。T组和C组的产犊至配种间隔分别为93±18天和99±22天。两组的产犊至受孕间隔有显著差异（T组为111±10天，C组为133±19天），配种至受孕间隔也得到类似结果（T组为18±15天，C组为31±19天）。T组的受孕率为80%，C组为59%，在繁殖季节开始时，受孕率与BW的相关性优于与BCS的相关性。C组和T组的断奶体重有差异（p<0.05）。从产后45天至繁殖季节开始，T组的母牛能量平衡为正（3%），而C组的母牛能量平衡为负（-0.1%）。得出的结论是，在亚热带条件下的粗放生产系统中，夜间将犊牛分开12小时可提高印度瘤牛的受孕率并改善犊牛断奶体重。
