Parker M O, O'Connor E A, McLeman M A, Demmers T G M, Lowe J C, Owen R C, Davey E L, Wathes C M, Abeyesinghe S M
Department of Veterinary Clinical Sciences, Centre for Animal Welfare, Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL7 9TA, UK.
Animal. 2010 Nov;4(11):1910-21. doi: 10.1017/S1751731110001084.
The effects of common and concurrent environmental stressors on the social behaviour of farm animals are poorly understood. Here, we report the results of a multifactorial experiment designed specifically to examine the individual, additive or interactive effects of elevated ammonia, noise and low light (LL) levels on the social behaviour of growing pigs. Social behaviour was measured in terms of the nature, frequency and duration of both initiated and response behaviours for 4 weeks following mixing of the groups. General activity patterns, group cohesion and social discrimination were also examined as a function of the environmental treatments. Elevated concentrations of atmospheric ammonia (∼20 v. <5 ppm) and LL intensity (∼40 v. 200 lux) had the most pronounced effects, particularly on the nature of social interactions, with pigs under these conditions showing more aggression in the early stages of the experiment. In addition, pigs exposed to a high level of mechanical noise representative of artificial ventilation (∼80 v. 40 dB [A]) were less submissive to aggressive acts, while pigs in ∼20 ppm ammonia showed more reciprocated aggression when in coincident LL (<40 lux). The results indicate that atmospheric ammonia at commonly experienced concentrations may undermine social stability, particularly in the presence of low lighting, though the mechanisms are currently unknown. These findings have implications for the welfare of growing pigs and hence policy makers and farmers alike, with respect to the improvement of welfare in intensive pig farming.
常见和同时存在的环境应激源对农场动物社会行为的影响尚不清楚。在此，我们报告一项多因素实验的结果，该实验专门设计用于研究氨气浓度升高、噪音和低光照（LL）水平对生长猪社会行为的个体、相加或交互作用。在猪群混群后的4周内，根据发起行为和反应行为的性质、频率和持续时间来衡量社会行为。还研究了一般活动模式、群体凝聚力和社会辨别能力与环境处理的关系。大气中氨气浓度升高（约20 ppm对<5 ppm）和LL强度（约40勒克斯对200勒克斯）产生的影响最为显著，特别是对社会互动的性质，在这些条件下的猪在实验早期表现出更多攻击性。此外，暴露于代表人工通风的高水平机械噪音（约80分贝对40分贝[A]）下的猪对攻击行为的顺从性较低，而处于约20 ppm氨气环境中的猪在同时处于低光照（<40勒克斯）时表现出更多相互攻击行为。结果表明，常见浓度的大气氨气可能会破坏社会稳定性，特别是在低光照条件下，尽管目前其机制尚不清楚。这些发现对生长猪的福利以及政策制定者和农民都有影响，涉及到集约化养猪中福利的改善。
