McArthur A J
Department of Physiology & Environmental Science, University of Nottingham School of Agriculture, Loughborough, U.K.
J Theor Biol. 1987 May 21;126(2):203-38. doi: 10.1016/s0022-5193(87)80229-1.
An equation based on heat transfer theory is developed to predict the rate of heat loss from a homeothermic vertebrate to the environment, specified by the air temperature, humidity, windspeed and radiation receipt. The analysis incorporates the animal's thermoregulatory responses--sweating ability, vasomotor action, and regulation of body-core temperature, metabolic and respiratory rate. The loss of heat and water vapour from cattle is used as an illustration, and particular attention is given to their heat balance in hot environments. The predicted rates of heat loss from cattle indoors at various air temperatures and humidities are consistent with experiments. Outdoors, intercepted solar radiation can reduce substantially heat loss through the body tissue when the air temperature is low. In contrast, at high air temperatures the heat dissipation may not be sensitive to the radiation load, although body-core temperature is. Increased rates of air movement can aggravate strain at low air temperatures, but mitigate strain in a hot environment.
基于传热理论建立了一个方程，用于预测恒温脊椎动物向环境散失热量的速率，该速率由气温、湿度、风速和辐射接收量确定。分析纳入了动物的体温调节反应——出汗能力、血管舒缩作用以及体核温度、代谢率和呼吸率的调节。以牛散失热量和水汽为例进行说明，并特别关注它们在炎热环境中的热平衡。预测的牛在不同气温和湿度条件下在室内的散热量与实验结果一致。在户外，当气温较低时，被拦截的太阳辐射可大幅减少通过身体组织的热量散失。相比之下，在高气温度时，尽管体核温度对辐射负荷敏感，但散热可能对辐射负荷不敏感。空气流动速率增加在低气温时会加剧应激，但在炎热环境中会减轻应激。
