School of Agriculture and Food Sciences, Animal Science Group, The University of Queensland, Gatton, QLD, 4343, Australia.
FD McMaster Laboratory, CSIRO Agriculture and Food, Armidale, NSW, 2350, Australia.
Int J Biometeorol. 2019 Jul;63(7):939-947. doi: 10.1007/s00484-019-01706-0. Epub 2019 Mar 13.
This study was conducted to determine the relationship between rectal temperature (T) and rumen temperature (T) and to assess if T could be used as a proxy measure of core body temperature (T) in feedlot cattle. Eighty Angus steers (388.8 ± 2.1 kg) were orally administered with rumen temperature boluses. Rumen temperatures were recorded at 10-min intervals over 128 days from all 80 steers. To define the suitability of T as an estimation of T, T were obtained from all steers at 7-day intervals (n = 16). Eight feedlot pens were used where there were 10 steers per pen (162 m). Shade was available in each pen (1.8 m/animal; 90% solar block). Climatic data were recorded at 30-min intervals, including ambient temperature (T; °C); relative humidity (RH; %); wind speed (WS; m/s) and direction; solar radiation (SR; W/m); and black globe temperature (BGT; °C). Rainfall (mm) was recorded daily at 0900 h. From these data, temperature humidity index (THI), heat load index (HLI) and accumulated heat load (AHL) were calculated. Individual 10-min T data were converted to an individual hourly average. Pooled mean hourly T data from the 128-day data were used to establish the diurnal rhythm of T where the mean minimum (39.19 ± 0.01 °C) and mean maximum (40.04 ± 0.01 °C) were observed at 0800 h and 2000 h respectively. A partial correlation coefficient indicated that there were moderate to strong relationships between T and T using both real-time (r = 0.55; P < 0.001) and hourly mean (r = 0.51; P < 0.001) T data. The mean difference between T and T was small using both real-time (0.16 ± 0.02 °C) and hourly mean T (0.13 ± 0.02 °C) data. Data from this study supports the hypothesis that T can be used as an estimate of T, suggesting that T can be used to measure and quantify heat load in feedlot cattle.
本研究旨在确定直肠温度（T）和瘤胃温度（T）之间的关系，并评估 T 是否可以作为饲养场牛核心体温（T）的替代测量指标。80 头安格斯阉牛（388.8 ± 2.1kg）口服瘤胃温度丸。在 128 天内，每隔 10 分钟记录 80 头阉牛的瘤胃温度。为了确定 T 作为 T 估计值的适用性，每隔 7 天从所有阉牛中获得 T 值（n=16）。使用 8 个饲养场围栏，每个围栏中有 10 头阉牛（162m）。每个围栏都有遮荫（1.8m/动物；90%遮阳）。每隔 30 分钟记录气候数据，包括环境温度（T；°C）；相对湿度（RH；%）；风速（WS；m/s）和方向；太阳辐射（SR；W/m）和黑球温度（BGT；°C）。每天 0900 时记录降雨量（mm）。根据这些数据，计算温度湿度指数（THI）、热负荷指数（HLI）和累积热负荷（AHL）。将个体 10 分钟 T 数据转换为个体每小时平均值。使用 128 天数据的汇总平均每小时 T 数据建立 T 的昼夜节律，平均最低（39.19 ± 0.01°C）和平均最高（40.04 ± 0.01°C）分别在 0800 时和 2000 时观察到。偏相关系数表明，使用实时（r=0.55；P<0.001）和每小时平均（r=0.51；P<0.001）T 数据，T 与 T 之间存在中度至强关系。使用实时（0.16 ± 0.02°C）和每小时平均 T（0.13 ± 0.02°C）数据，T 与 T 之间的平均差异较小。本研究的数据支持 T 可作为 T 的估计值的假设，表明 T 可用于测量和量化饲养场牛的热负荷。
