Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Production Animal Clinical Sciences, P.O. Box 8146 dep., N-0033 Oslo, Norway.
Norwegian Institute of Public Health, Division of Epidemiology, Marcus Thranes gate 6, P.O. Box 4404, 0403 Oslo, Norway.
Poult Sci. 2018 Jul 1;97(7):2249-2257. doi: 10.3382/ps/pey033.
Footpad dermatitis is a condition that causes lesions on the plantar surface of the footpads in growing turkeys. Potential inflammatory processes and pain associated with increasing severity of footpad dermatitis raise animal welfare concerns. This study investigated whether the temperature of the plantar surface of the foot (the footpads and the entire plantar foot including interdigital membranes) assessed with infrared thermography reflects severity of mild footpad dermatitis as assessed with a Visual Analogue Scale in 80 turkey toms at 10 weeks of age. In order to study effects of a potential emotional arousal due to the testing procedures, effects of sequential testing order and duration of handling of the turkeys was included in the model. Footpad temperatures were significantly lower than foot temperatures (P < 0.001, R2 = 0.57, -3.36°C ± 0.28°C), and higher visual analogue scale scores were anti-correlated with footpad (-0.06°C ± 0.037°C) and foot temperatures (-0.07°C ± 0.066°C). Furthermore, a negative association between footpad temperature and handling time (-0.02 ± 0.0227, P = 0.048), and a non-linear association between foot and footpad temperatures and sequential testing order, were found (P<0.001). The results indicate that severity of mild footpad dermatitis as scored visually was associated with the temperatures of the plantar surface of the foot and footpads, and that thermal imaging therefore represents a novel tool for the reliable and non-invasive early detection of subclinical foot pathologies in turkeys. The association was negative, and the findings therefore indicate that potential inflammatory processes in the epidermis at this early stage of footpad dermatitis are negligible, and/or that the hyperkeratosis of the surface keratin shielded heat emission from the footpads. The associations between surface temperatures, handling time, and sequential testing order suggest an emotional arousal in response to the experimental procedures, and these factors need to be considered when applying infrared thermography in future studies of leg health in turkeys.
脚垫皮炎是一种导致生长火鸡脚垫表面出现病变的疾病。潜在的炎症过程和与脚垫皮炎严重程度增加相关的疼痛引起了动物福利问题。本研究调查了用红外线热成像评估的足底表面温度（包括脚垫和整个足底，包括趾间膜）是否反映了 10 周龄 80 只火鸡公鸡轻度脚垫皮炎的严重程度，用视觉模拟量表进行评估。为了研究由于测试程序而导致的潜在情绪唤醒的影响，测试顺序和火鸡处理时间的持续时间的影响也包括在模型中。脚垫温度明显低于脚部温度（P<0.001，R2=0.57，-3.36°C±0.28°C），并且较高的视觉模拟量表评分与脚垫（-0.06°C±0.037°C）和脚部温度（-0.07°C±0.066°C）呈反相关。此外，还发现脚垫温度与处理时间之间存在负相关（-0.02±0.0227，P=0.048），以及脚部和脚垫温度与测试顺序之间的非线性关联（P<0.001）。结果表明，视觉评分的轻度脚垫皮炎严重程度与足底表面和脚垫的温度相关，因此热成像代表了一种可靠且非侵入性的早期检测火鸡亚临床足部病变的新工具。这种关联是负相关的，这表明在脚垫皮炎的这个早期阶段，表皮中的潜在炎症过程可以忽略不计，或者表面角蛋白的过度角化屏蔽了来自脚垫的热辐射。表面温度、处理时间和测试顺序之间的关联表明对实验程序有情绪唤醒，在未来的火鸡腿部健康研究中应用红外线热成像时需要考虑这些因素。
