Submitted to: European Association of Animal Production Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/31/2003
Publication Date: 9/8/2003
Citation: HAHN, G.L., MADER, T.L., EIGENBERG, R.A. PERSPECTIVES ON DEVELOPMENT OF THERMAL INDICES FOR ANIMAL STUDIES AND MANAGEMENT. EUROPEAN ASSOCIATION OF ANIMAL PRODUCTION PROCEEDINGS. 2003. pg 31-44. Interpretive Summary: Thermal climate influences animals through heat exchanges with the environment. This is a complex process influencing animal performance, health, and well-being. Air temperature is an important factor in the heat exchange process, but is often inadequate to represent such influences. Therefore, there have been many attempts to better represent environmental influences by means of "thermal index" values. These values combine air temperature and other measures of the environment, such as humidity, wind, and solar radiation. This report provides a historical background but emphasizes approaches that are promising for further development of thermal indices. Applications are for farm animal studies and management.
Technical Abstract: Heat exchanges with the environment are a crucial process for maintaining homeothermy by humans and other animals. These exchanges involve heat production, conservation, and dissipation, and are dependent on both biological and physical factors. The complexity of these exchanges have led to many attempts to represent the environmental aspects by surrogate thermal indices as a basis for assessing the biological effect and consequent impact of the thermal environment. Resultant index values represent effects produced by the heat exchange process. For humans, comfort assessment is primary; for animals, assessing performance, health, and well-being have been foremost. This dichotomy of approaches is discussed from the perspectives of past and current indices, and considerations for future efforts. Emphasis is on thermal indices useful in animal studies and applications, with a view toward strategic and tactical decisions for rational environmental management. Numerous illustrative examples are included.