Technical Abstract: High environmental temperatures challenge livestock production but technology exists to offset the challenge if producers have made appropriate strategic decisions. Key issues include understanding the hazards of high temperatures, being prepared to offer relief from the heat, recognize when an animal is in danger, and take appropriate action. This paper describes our efforts to develop biological response functions; assess climatic probabilities and perform associated risk analyses; provide inputs for computer models used to make environmental management decisions; and evaluate threshold temperatures as estimates of critical temperature limits for swine, cattle and sheep.