Verdon Megan, Morrison R S, Hemsworth P H
Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Victoria, 3010, Australia; Tasmanian Institute of Agriculture, Faculty of Science, Engineering and Technology, University of Tasmania, Tasmania, 7320, Australia.
Rivalea Australia, Corowa, New South Wales, 2646, Australia.
Behav Processes. 2018 May;150:17-24. doi: 10.1016/j.beproc.2018.02.016. Epub 2018 Feb 21.
This experiment examined the effects of group composition on sow aggressive behaviour and welfare. Over 6 time replicates, 360 sows (parity 1-6) were mixed into groups (10 sows per pen, 1.8 m/sow) composed of animals that were predicted to be aggressive (n = 18 pens) or groups composed of animals that were randomly selected (n = 18 pens). Predicted aggressive sows were selected based on a model-pig test that has been shown to be related to the aggressive behaviour of parity 2 sows when subsequently mixed in groups. Measurements were taken on aggression delivered post-mixing, and aggression delivered around feeding, fresh skin injuries and plasma cortisol concentrations at days 2 and 24 post-mixing. Live weight gain, litter size (born alive, total born, stillborn piglets), and farrowing rate were also recorded. Manipulating the group composition based on predicted sow aggressiveness had no effect (P > 0.05) on sow aggression delivered at mixing or around feeding, fresh injuries, cortisol, weight gain from day 2 to day 24, farrowing rate, or litter size. The lack of treatment effects in the present experiment could be attributed to (1) a failure of the model-pig test to predict aggression in older sows in groups, or (2) the dependence of the expression of the aggressive phenotype on factors such as social experience and characteristics (e.g., physical size and aggressive phenotype) of pen mates. This research draws attention to the intrinsic difficulties associated with predicting behaviour across contexts, particularly when the behaviour is highly dependent on interactions with conspecifics, and highlights the social complexities involved in the presentation of a behavioural phenotype.
本实验研究了群体组成对母猪攻击行为和福利的影响。在6次重复实验中，将360头母猪（胎次1 - 6）分成若干组（每栏10头母猪，每头母猪占1.8平方米），一组由预计具有攻击性的母猪组成（18栏），另一组由随机挑选的母猪组成（18栏）。预计具有攻击性的母猪是根据一种模型猪测试挑选出来的，该测试已被证明与经产2胎母猪随后混群时的攻击行为有关。记录了混群后发生的攻击行为、喂食前后的攻击行为、混群后第2天和第24天的新鲜皮肤损伤以及血浆皮质醇浓度。还记录了体重增加、产仔数（活产、总产、死胎仔猪数）和分娩率。根据预计的母猪攻击性来操纵群体组成，对混群时或喂食前后的母猪攻击行为、新鲜损伤、皮质醇、第2天至第24天的体重增加、分娩率或产仔数均无影响（P>0.05）。本实验中缺乏处理效应可能归因于：（1）模型猪测试未能预测群体中年龄较大母猪的攻击性；或（2）攻击性行为表型的表达依赖于社会经验和栏内同伴的特征（如体型和攻击性行为表型）等因素。这项研究提请人们注意预测跨情境行为所固有的困难，特别是当行为高度依赖于与同种个体的相互作用时，并突出了行为表型呈现中所涉及的社会复杂性。
