不同活动空间对群养母猪的攻击行为与皮质醇浓度的影响

畜牧编辑

　　不同活动空间对群养母猪的攻击行为与皮质醇浓度的影响

　　P. H. Hemsworth, R.S. Morrison, A. J.Tilbrook, K. L. Butler, M. Rice和S. J. Moeller

　　活动面积是群养母猪攻击行为多少与应激水平的重要影响因素。本试验旨在综合评估混群至受精后27天这段时间内，在1.45-2.90m2/头范围内活动面积对母猪的攻击行为、应激水平和生殖的影响。之前的试验结果表明不同试验农场之间、试验农场不同圈舍之间母猪的攻击行为和应激水平存在很大的空间变异性。为了减少试验猪舍的空间变异度，本试验在4个独立区域内选取3个相近圈舍（规格一致）来饲养群规模各异（10-20头）的母猪，每个圈舍9个重复（每个重复180头母猪），以此来评估6种不同空间规格对母猪的影响。每个圈舍的空间规格设置随机分配。尽管本试验中猪舍空间规格的差异是由猪群规模来决定划分的可能会有争议，但根据我们之前有关猪群规模效应的研究数据来看，对于每圈10-80头母猪来说，空间和猪群规模在对母猪攻击行为、应激状态和生殖的影响方面并没有很多的互作。
本试验中母猪在受精后四天内转入试验栏，每天在地板上投料4次（每头母猪每天饲喂2.5kg）。混群后的第2天和第26天，对采食时母猪的攻击行为（撕咬和撞击）和血浆中皮质醇浓度进行考量与检测。在计算了重复内的重复与随机空间位置效应后采用约束最大似然混合模型来分析各处理的效应。地板空间面积对第二天采食时母猪的攻击行为和第二天的血浆皮质醇浓度均表现出一致的线性关系（P = 0.0003），随着空间的增大，攻击行为和应激水平逐渐降低。然而，在第26天的检测结果来看，空间对攻击行为和应激水平均无影响（显著性分别为P = 0.14 和P = 0.79）。这一结果显示在混群后的短时间内母猪拥有更大的空间可减少其攻击行为和应激水平，但随着时间的延长，母猪可能会对较小的空间产生适应性。妊娠母猪的分圈可采用如下策略：混群后的短时间给予较大空间，妊娠后期给予较小的空间，这样可能会兼顾到动物福利和经济因素，但这一结论很明显需要更进一步的证实。

　　Effects of varying floor space on aggressive behavior and cortisol concentrations in group-housed sows

　　P. H. Hemsworth, R.S. Morrison, A. J.Tilbrook, K. L. Butler, M. Rice and S. J. Moeller

　　Floor space is an important determinant of aggression and stress in group-housed sows, and the aim of the present experiment was to comprehensively examine the effects of floor space in the range of 1.45 to 2.90 m2/sow from mixing until 27 d after insemination on aggression, stress, and reproduction of group-housed sows. A previous experiment on the effects of floor space indicated spatial variability across and along the research facility in both sow aggression and stress. To minimize this spatial variability within the research facility, similar-sized pens but with varying groups sizes (10–20) in 4 separate blocks of 3 contiguous pens within each of 9 time replicates (180 sows/replicate) were used to examine 6 space allowances (1.45–2.9 m2/sow). Space treatments were appropriately randomized to pens. Although it may be argued that space allowance is confounded with group size in this design, there was no evidence in our previous experiment of group size effects, for pens of 10 to 80 sows, or appreciable interactions between space and group size on aggression, stress,and reproduction. In the present experiment, sows were introduced to treatments within 4 d of insemination and were floor fed 4 times per day (2.5 kg/sow perd). On both Days 2 and 26 after mixing, aggressive behavior (bites and knocks) at feeding and plasma cortisol concentrations were measured. Restricted maximum likelihood mixed model analyses were used to examine the treatment effect after accounting for replicate and random spatial location effects within replicate.There was a consistent linear effect of floor space allowance on aggression at feeding at Day 2 (P < 0.0001) and plasma cortisol concentrations at Day 2 (P= 0.0003), with aggression and stress declining with increasing space. However, there were no effects of space allowance on aggression and stress at Day 26 (P= 0.14 and P = 0.79, respectively). These results show that increased floor space in the immediate post-mixing period reduces aggression and stress and that sows may adapt to reduced floor space over time. A strategy of staged-gestation penning, with more space immediately after mixing and less space later in gestation, may address both animal welfare and economic considerations, but this clearly requires further examination。
翻译: 李光燃
来源：猪营养国际论坛CSIS