Price E O, Harris J E, Borgward R E, Sween M L, Connor J M
Department of Animal Science, University of California, Davis 95616, USA.
J Anim Sci. 2003 Jan;81(1):116-21. doi: 10.2527/2003.811116x.
The purpose of this study was to examine the hypothesis that fenceline contact between beef calves and cows at weaning reduces indices of behavioral distress and associated temporary reductions in weight gain. One hundred Angus/Hereford-cross calves were randomly assigned to five treatments for 7 d in each of 3 yr to determine the effect of different weaning techniques on their behavior and subsequent growth. Treatments were 1) fenceline separation from dams on pasture (F-P), 2) total separation from dams on pasture (S-P), 3) total separation from dams in a drylot (corral) preconditioned to hay (S-D-P), 4) total separation from dams in a drylot not preconditioned to hay (S-D-NP), and 5) nonweaned controls on pasture (C-P). At the end of the 7-d postweaning period, all calves were placed on pasture in large groups. Calves were weighed weekly for 10 wk. In the days following weaning, F-P and C-P calves spent more time eating (grazing or eating hay) than S-P and S-D-NP calves (P < 0.05). The S-P calves spent more time walking (pacing) than calves in the other four treatments (P < 0.05), which did not differ. The S-P calves also spent less time lying down than C-P, F-P, and S-D-P calves (P < 0.05); S-P and S-D-NP calves did not differ in lying time. The F-P calves vocalized less than S-P and S-D-NP calves (P < 0.05). In general, treatment differences were greatest during the first 3 d following weaning with d 2 (20 to 30 h after weaning) showing the greatest disparity. The F-P calves spent approximately 60% of their time within 3 m of the fence separating them from their dams during the first 2 d following weaning, whereas F-P cows spent about 40% of their time within 3 m of the fence during this period. Postweaning cumulative body weight gains of the F-P calves were greater than the gains recorded for the calves in the three totally separated treatments (which did not differ). The F-P calves gained 95% more weight than the average calf in the three totally separated treatments in the first 2 wk and were still heavier at 10 wk (21.4 vs 11.0 kg, respectively, at 2 wk and 50.0 vs 38.2 kg, respectively, at 10 wk; P < 0.05). It was concluded that providing fenceline contact between beef calves and cows for 7 d following weaning reduces behavioral indices of distress seen in the totally separated calves. In addition, fenceline contact with dams at weaning minimizes losses in weight gain in the days following separation. Totally separated calves did not compensate for these early losses in weight gain even after 10 wk.
断奶时肉牛犊与母牛围栏接触可降低行为应激指标，并减少相关的体重增加暂时减少。在3年中的每年，将100头安格斯/赫里福德杂交犊牛随机分配到5种处理中，每种处理持续7天，以确定不同断奶技术对其行为和后续生长的影响。处理方式分别为：1）在牧场上与母牛围栏分隔（F-P）；2）在牧场上与母牛完全分隔（S-P）；3）在预先适应干草的干栏（畜栏）中与母牛完全分隔（S-D-P）；4）在未预先适应干草的干栏中与母牛完全分隔（S-D-NP）；5）在牧场上的未断奶对照（C-P）。在断奶后7天结束时，所有犊牛被大群安置在牧场上。犊牛每周称重，持续10周。在断奶后的几天里，F-P和C-P组的犊牛比S-P和S-D-NP组的犊牛花费更多时间进食（放牧或吃干草）（P < 0.05）。S-P组的犊牛比其他四种处理组的犊牛花费更多时间行走（踱步）（P < 0.05），其他四种处理组之间无差异。S-P组的犊牛躺卧时间也比C-P、F-P和S-D-P组的犊牛少（P < 0.05）；S-P和S-D-NP组的犊牛躺卧时间无差异。F-P组的犊牛比S-P和S-D-NP组的犊牛发声少（P < 0.05）。一般来说，处理差异在断奶后的前3天最大，第2天（断奶后20至30小时）差异最为明显。断奶后的前2天，F-P组的犊牛约60%的时间处于将其与母牛分隔的围栏3米范围内，而在此期间F-P组的母牛约40%的时间处于围栏3米范围内。F-P组犊牛断奶后的累积体重增加大于三种完全分隔处理组犊牛的增重（三种完全分隔处理组之间无差异）。在最初的2周内，F-P组的犊牛比三种完全分隔处理组的平均犊牛体重多增加95%，并且在10周时仍较重（2周时分别为21.4千克和11.0千克，10周时分别为50.0千克和38.2千克；P < 0.05）。得出的结论是，断奶后7天让肉牛犊与母牛围栏接触可降低完全分隔犊牛出现的行为应激指标。此外，断奶时与母牛围栏接触可使断奶后几天内的体重增加损失最小化。即使在10周后，完全分隔的犊牛也没有弥补这些早期的体重增加损失。
