Assessment of indices of thermal stress indicators among male buffaloes reared in the Eastern Brazilian Amazon

ABSTRACT. This research aimed to determine the most appropriate thermal comfort index for buffaloes reared in the Eastern Amazon, Pará, Brazil. Twenty male Murrah buffaloes were used, and data on climate variables, rectal temperature (RT), body surface temperature (BST), and respiratory rate (RR) were recorded. Subsequently, the following indices were calculated: Temperature and Humidity Index (THI), Global Temperature and Humidity Index (GTHI), Benezra’s Thermal Comfort Index (BTCI), Ibéria’s Heat Tolerance Index (IHTI), the general, effective, and practical Buffalo Comfort Climatic Conditions Indices (BCCCIg, BCCCIe, and BCCCIp, respectively) and the general, effective, and practical Buffalo Environmental Comfort Indices (BECIg, BECIe, and BECIp, respectively) in the morning and afternoon. Higher values for THI, GTHI, RT, BST, RR, BTCI, BCCCIg, BCCCIe, BCCCIp, BECIg, BECIe, and BECIp were observed in the afternoon, and the highest IHTI values were found in the morning. A positive correlation was found among the physiological variables and THI, GTHI, BTCI, BCCCIg, BECIg, BCCCIe, BECIe, BCCCIp, BECIp, while a negative correlation was found for RT and BST with IHTI. The indices THI, GTHI, BCCCIg, BECIg, BCCCIe, BECIe, BCCCIp, and BECIp were determined to be very efficient to assess the thermal comfort status of buffaloes under the conditions of the present research.

摘要。本研究旨在明确巴西帕拉州东亚马逊地区饲养的摩拉水牛最适宜的热舒适评价指数。本试验选用20头公摩拉水牛作为研究对象，记录了气候变量、直肠温度（rectal temperature, RT）、体表温度（body surface temperature, BST）以及呼吸频率（respiratory rate, RR）相关数据。随后计算了以下指数：温湿度指数（Temperature and Humidity Index, THI）、全球温湿度指数（Global Temperature and Humidity Index, GTHI）、贝内兹拉热舒适指数（Benezra’s Thermal Comfort Index, BTCI）、伊贝里亚耐热指数（Ibéria’s Heat Tolerance Index, IHTI）、通用型、有效型与实用型水牛舒适气候条件指数（Buffalo Comfort Climatic Conditions Indices，分别记为BCCCIg、BCCCIe与BCCCIp），以及通用型、有效型与实用型水牛环境舒适指数（Buffalo Environmental Comfort Indices，分别记为BECIg、BECIe与BECIp），上述指数均分别于上午、下午两个时段完成计算。研究结果显示，午后时段的THI、GTHI、RT、BST、RR、BTCI、BCCCIg、BCCCIe、BCCCIp、BECIg、BECIe与BECIp数值均更高，而IHTI的最高值则出现在上午时段。生理变量与THI、GTHI、BTCI、BCCCIg、BECIg、BCCCIe、BECIe、BCCCIp、BECIp之间呈正相关关系，而直肠温度与体表温度则与IHTI呈负相关。本研究设定的试验条件下，THI、GTHI、BCCCIg、BECIg、BCCCIe、BECIe、BCCCIp与BECIp均可高效评估水牛的热舒适状态。