Heat Stress in Dairy Cattle: Detection and Strategies for Effective Management

Heat stress problems in dairy cattle are rather common in tropical and subtropical regions. Over the last decade, however, we have observed several days and even periods of heat stress in European countries and the United States too, affecting both humans and cattle. While in the tropical and subtropical regions dairy farmers may be used to handle such problems more or less adequately, it is not sure that European and American farmers, or their veterinary practitioners, are sufficiently prepared to diagnose heat stress and to properly deal with those problems, nor that they understand the negative consequences of heat stress for the dairy cattle, such as in the area of metabolism in general, and of production, reproduction and health in particular. Especially high yielding cows are susceptible, due to the increased level of their metabolism. This chapter presents the occurrence of heat stress, its signs and diagnosis, and major practical management measures to control and to prevent heat stress. These measures can be divided into general measures (a Good Heat Stress Management code of practice) and farm-specific measures (the application of appropriate cooling and cooling cycles). It is concluded that veterinary practitioners can play a substantial role as a consultant-coach to farmers for both understanding heat stress and implementing the measures. Finally, the most adequate solution to repeated heat stress problems on dairy farms, in terms of applying cooling cycles and the necessary equipment, is the tailor-made, individual farm approach.