Thermal comfort indices (TCIs) have been developed to assess heat stress and model the relationship between thermal parameters (e.g. dry-bulb temperature) and animal responses (e.g. daily milk yield, DMY). The published models typically include temperature humidity index (THI), black globe humidity index, environmental stress index, equivalent temperature index, heat load index, respiration rate index and comprehensive climate index. This study was conducted to compare the performance of these published TCIs using data collected from a robotic farm situated in a subtropical climate region. The comparison also included models formulated between basic thermal parameters and animal responses (DMY and milk temperature (MT)). The statistical analyses found dry-bulb temperature can provide a similar level of performance to other TCIs in assessing heat stress. The spatial variability between on-farm measurements and the local weather station can be neglected when modelling with TCIs and MT. For cows with an average DMY of 31 kg cow−1 d−1, the threshold for significant decline of DMY was reported as THI >64 (P

中文翻译：

---

机器人奶牛场热应激建模。第 1 部分：作为生产损失指标的热舒适指数

已开发出热舒适指数 (TCIs) 来评估热应激并模拟热参数（例如干球温度）与动物反应（例如每日产奶量，DMY）之间的关系。公布的模型通常包括温度湿度指数（THI）、黑球湿度指数、环境压力指数、等效温度指数、热负荷指数、呼吸率指数和综合气候指数。本研究旨在使用从位于亚热带气候区域的机器人农场收集的数据来比较这些已发布的 TCI 的性能。比较还包括在基本热参数和动物反应（DMY 和牛奶温度 (MT)）之间建立的模型。统计分析发现，在评估热应力方面，干球温度可以提供与其他 TCI 相似的性能水平。使用 TCI 和 MT 建模时，可以忽略农场测量值和当地气象站之间的空间变异性。对于平均 DMY 为 31 kg cow−1 d−1 的奶牛，DMY 显着下降的阈值报告为 THI >64（P