A new heat load index for feedlot cattle
A new heat load index for feedlot cattle
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DOI：
10.2527/jas.2007-0305
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Lisle, A.
中科院分区：
文献类型：
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作者：
Gaughan, J. B.;Mader, T. L.;Lisle, A.
就福利和生产性能而言，预测极端气候变量对牲畜的影响的能力很重要。一种结合温度和湿度的指数(THI)已经被用于评估牛的热应激40多年了。然而，THI不包括重要的气候变量，如太阳负荷和风速(WS，m/S)。同样，它不包括管理因素(遮荫的影响)或动物因素(基因差异)。在8个夏季中，共有11,669头牛、2,344头牛、2,142头牛、1,595头牛被用于开发和测试饲养场牛的热负荷指数(HLI)。利用2,490头安格斯公牛的喘息评分(PS)，初步开发了一种新的HLI，它包含了黑地球(BG)温度(摄氏度)、相对湿度(RH，十进制形式)和WS。HLI由两部分组成，基于25摄氏度的BG温度阈值：HLIBG和GT；25=8.62+(0.38 x RH)+(1.55 x BG)-(0.5 x WS)+e((2.4-WS))和HLIBG
The ability to predict the effects of extreme climatic variables on livestock is important in terms of welfare and performance. An index combining temperature and humidity (THI) has been used for more than 4 decades to assess heat stress in cattle. However, the THI does not include important climatic variables such as solar load and wind speed (WS, m/s). Likewise, it does not include management factors (the effect of shade) or animal factors (genotype differences). Over 8 summers, a total of 11,669 Bos taurus steers, 2,344 B. taurus crossbred steers, 2,142 B. taurus x Bos indicus steers, and 1,595 B. indicus steers were used to develop and test a heat load index (HLI) for feedlot cattle. A new HLI incorporating black globe (BG) temperature (degrees C), relative humidity (RH, decimal form), and WS was initially developed by using the panting score (PS) of 2,490 Angus steers. The HLI consists of 2 parts based on a BG temperature threshold of 25 degrees C: HLIBG>25 = 8.62 + (0.38 x RH) + (1.55 x BG) - (0.5 x WS) + e((2.4-WS)), and HLIBG