Under normal conditions, animals are in physiological homeostasis-in other words, all bodily systems are functioning normally. Heat stress poses a physiological challenge to breeding females because their bodies are programmed first to survive and then to reproduce. It is difficult to assess the physiological status of an animal and determine at what point it will return to reproductive readiness after a period of stress. Each animal may be at a different level of responsiveness during high temperatures. However, we know from experience that in the fall, when environmental conditions return to "normal," a consistent and regular estrus returns. Some of the management strategies outlined below will be more effective than others. Also, each strategy's effectiveness can be highly variable because females in a heat-stressed herd will be at different levels of reproductive competence. In short, some females may require greater levels or duration of intervention to return to normal reproduction.