Boileau Anik, Farish Marianne, Turner Simon P, Camerlink Irene
Animal Behaviour & Welfare, Animal and Veterinary Sciences Research Group, Scotland's Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG, UK; Sept-Îles Education and Research Centre (CERSI), 1008, Brochu, Sept-Îles, Québec G4R 2Y8, Canada.
Animal Behaviour & Welfare, Animal and Veterinary Sciences Research Group, Scotland's Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG, UK.
Physiol Behav. 2019 Oct 15;210:112637. doi: 10.1016/j.physbeh.2019.112637. Epub 2019 Jul 30.
Infrared thermography (IRT) or thermal imaging is increasingly being used as a non-invasive method to gain information on animals' physiological and emotional state. IRT has the potential to serve as a non-invasive quantitative assessment method but few studies have examined its utility in predicting welfare-relevant outcomes of dynamic scenarios relevant to commercial farming. This study used 1284 thermal images taken from 46 pigs in a controlled test environment while they engaged in an agonistic encounter (dyadic contest) at 13 wk. of age. Images were taken of the complete body from a dorsal perspective. A pilot study indicated that a rectangular thermal window on the back region was the most suitable and reliable area for obtaining temperature data in this situation. From this thermal window, the average, minimum and maximum temperature, standard deviation and coefficient of variation (CV) were obtained. These were analysed in relation to contest phase (from non-contact assessment, through escalated fighting to retreat), fight occurrence, contest duration, contest outcome (winner/loser status) and changes in blood glucose, blood lactate, and skin injuries. Variables showed a strong change in response to the moment of contest resolution (retreat of the loser); temperatures reduced sharply and CV increased, but did not differ between winners and losers. Contests that included a fight showed lower temperatures. Contest duration, body weight and sex only had minor influences on the temperatures. As the drop in temperature at contest resolution was irrespective of contest intensity, and the pattern was similar in winners and losers, this data potentially reflects vasoconstriction as a result of psychological stress rather than solely a physiological change. The study shows that peripheral temperature, as recorded by IRT, responds to the intensity and phases of a contest and may allow new insight into the physiological and welfare outcomes of aggressive behaviour.
红外热成像（IRT）或热成像正越来越多地被用作一种非侵入性方法，以获取有关动物生理和情绪状态的信息。IRT有潜力作为一种非侵入性定量评估方法，但很少有研究考察其在预测与商业养殖相关的动态场景中与福利相关结果方面的效用。本研究在可控测试环境中，对46头13周龄猪在进行争斗性遭遇（二元对抗）时拍摄了1284张热图像。从背部视角拍摄猪的全身图像。一项初步研究表明，在这种情况下，背部区域的一个矩形热窗是获取温度数据最合适、最可靠的区域。从这个热窗获取平均温度、最低温度、最高温度、标准差和变异系数（CV）。分析这些数据与对抗阶段（从非接触评估、升级战斗到撤退）、战斗发生情况、对抗持续时间、对抗结果（胜者/败者状态）以及血糖、血乳酸和皮肤损伤变化之间的关系。变量在对抗结束时刻（败者撤退）有强烈变化；温度急剧下降，CV增加，但胜者和败者之间没有差异。包括战斗的对抗显示温度较低。对抗持续时间、体重和性别对温度的影响较小。由于对抗结束时的温度下降与对抗强度无关，且胜者和败者的模式相似，这些数据可能反映了心理压力导致的血管收缩，而不仅仅是生理变化。该研究表明，IRT记录的外周温度对对抗的强度和阶段有反应，可能为攻击行为的生理和福利结果提供新的见解。
