Heat stress as it affects animal production.

It is well documented that the stress of hot environments lowers productive and reproductive efficiency, in farm animals. Likewise, research information is available to aid in the management of livestock in such adverse conditions. However, practical methods to achieve the desired levels of productive and reproductive performance are lacking. Summer forages that will support a high level of productivity in subtropic and tropic regions are needed for ruminants. More critical information is needed on the total dietary needs of all farm animals in hot environments. Dietary emphasis should be to increase intake or to alter levels of proteins, amino acids or other nutrients to improve the conversion of feed units into production units. Increasing nutrient intake to support a higher level of production will render animals more sensitive, in terms of productive efficiency, to environmental modifications that improve comfort. This should be especially pertinent in the humid Southeast and other regions where production responses to environmental modifications have been variable. There is limited information on the effect of the night cooling cycle on productive efficiency and on the effect of severe heat stress on reproductive phenomena not related to conception.