不同活動空間對群養母豬的攻擊行為與皮質醇濃度的影響

畜牧編輯

　　不同活動空間對群養母豬的攻擊行為與皮質醇濃度的影響

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

　　活動面積是群養母豬攻擊行為多少與應激水平的重要影響因素。本試驗旨在綜合評估混群至受精后27天這段時間內，在1.45-2.90m2/頭范圍內活動面積對母豬的攻擊行為、應激水平和生殖的影響。之前的試驗結果表明不同試驗農場之間、試驗農場不同圈舍之間母豬的攻擊行為和應激水平存在很大的空間變異性。為了減少試驗豬舍的空間變異度，本試驗在4個獨立區域內選取3個相近圈舍（規格一致）來飼養群規模各異（10-20頭）的母豬，每個圈舍9個重復（每個重復180頭母豬），以此來評估6種不同空間規格對母豬的影響。每個圈舍的空間規格設置隨機分配。盡管本試驗中豬舍空間規格的差異是由豬群規模來決定劃分的可能會有爭議，但根據我們之前有關豬群規模效應的研究數據來看，對于每圈10-80頭母豬來說，空間和豬群規模在對母豬攻擊行為、應激狀態和生殖的影響方面并沒有很多的互作。
本試驗中母豬在受精后四天內轉入試驗欄，每天在地板上投料4次（每頭母豬每天飼喂2.5kg）。混群后的第2天和第26天，對采食時母豬的攻擊行為（撕咬和撞擊）和血漿中皮質醇濃度進行考量與檢測。在計算了重復內的重復與隨機空間位置效應后采用約束最大似然混合模型來分析各處理的效應。地板空間面積對第二天采食時母豬的攻擊行為和第二天的血漿皮質醇濃度均表現出一致的線性關系（P = 0.0003），隨著空間的增大，攻擊行為和應激水平逐漸降低。然而，在第26天的檢測結果來看，空間對攻擊行為和應激水平均無影響（顯著性分別為P = 0.14 和P = 0.79）。這一結果顯示在混群后的短時間內母豬擁有更大的空間可減少其攻擊行為和應激水平，但隨著時間的延長，母豬可能會對較小的空間產生適應性。妊娠母豬的分圈可采用如下策略：混群后的短時間給予較大空間，妊娠后期給予較小的空間，這樣可能會兼顧到動物福利和經濟因素，但這一結論很明顯需要更進一步的證實。

　　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。
翻譯: 李光燃
來源：豬營養國際論壇CSIS