State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
Int J Biometeorol. 2019 Mar;63(3):327-336. doi: 10.1007/s00484-018-01666-x. Epub 2019 Jan 24.
The aim of this study was to better understand the inflection point of RT and BSTs and measure different body surface temperatures (BSTs) under different temperature-humidity index (THI) conditions. A total of 488 Holstein dairy cows were chosen to manually measure rectal temperature (RT) and BSTs including left side of eye, ear, cheek, forehead, flank, rump, fore udder, and rear udder by infrared thermography for 14 times. Those measurements included six times under high THI (THI > 78), three times under moderate THI (72 ≤ THI ≤ 78), and five times under low THI (THI < 72). Results showed that BSTs were affected by THI conditions (P < 0.01). The THI conditions where mean and maximum forehead temperatures started to increase rapidly (71.4 and 66.8) were lower than that where RT started to increase rapidly (74.1). The correlation coefficients of mean and maximum forehead temperatures to THI were 0.808 and 0.740, and were 0.557 and 0.504 to RT, all showing the highest as compared to other region temperatures with THI and RT, respectively. Thus, we conclude that BSTs are more sensitive to thermal environment than RT, suggesting the variability of BST to reflect body core temperature. In addition, the forehead is a relatively reliable region to assess the heat stress reflecting RT compared to the eye, ear, cheek, flank, rump, fore udder, and rear udder regions.
本研究旨在更好地了解直肠温度（RT）和体核温度（BSTs）的转折点，并测量不同温湿度指数（THI）条件下的不同体表温度（BSTs）。选择了 488 头荷斯坦奶牛，通过红外热成像技术手动测量了直肠温度（RT）和 BSTs，包括左眼、耳朵、脸颊、额头、侧腹、臀部、前乳房和后乳房，共测量了 14 次。这些测量包括高 THI（THI>78）下的 6 次、中 THI（72≤THI≤78）下的 3 次和低 THI（THI<72）下的 5 次。结果表明，BSTs 受到 THI 条件的影响（P<0.01）。额头平均和最高温度开始快速上升的 THI 条件（71.4 和 66.8）低于 RT 开始快速上升的 THI 条件（74.1）。额头平均和最高温度与 THI 的相关系数分别为 0.808 和 0.740，与 RT 的相关系数分别为 0.557 和 0.504，均高于其他区域温度与 THI 和 RT 的相关性。因此，我们得出结论，BSTs 比 RT 对热环境更敏感，表明 BST 的变化可以反映体核温度。此外，与眼睛、耳朵、脸颊、侧腹、臀部、前乳房和后乳房相比，额头是评估反映 RT 的热应激的一个相对可靠的区域。
