科研之友
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摘要
Heat stress will cause a dairy cow that is highly productive under normal conditions to produce far less, milk and also to delay its gestation cycle. The corresponding economic losses have become significant as the dairy industry, following the population growth in the U.S., expands into warmer climatic zones. Global warming, higher energy costs, and ever more scarce water resources will further exacerbate the heat stress problem in the foreseeable future. Currently in use systems designed to mitigate heat stress work well under certain conditions, but as temperature and humidity levels rise, most such systems lose their ability to prevent heat stress. The present study investigates the efficacy of using a heat exchanger placed underneath the stall bedding to alleviate the conditions that lead to heat stress. The computational model incorporates physiological and physical characteristics of a cow as well as specific heat and mass transport mechanisms including non-Darcy flow and sweating. The results show that a system that employs conductive cooling could alleviate heat stress during hot and humid weather even when conventional systems cannot.
- 出版日期2013-12
