"Fescue toxicosis" is the general term used for the clinical diseases that can affect cattle consuming endophyte-infected tall fescue. Tall-fescue pastures containing ergot alkaloids are responsible for the toxic effects observed in livestock, including hyperthermia (elevated body temperature), gangrene of the extremities, decreased weight gain, and poor reproductive performance. Clinical signs vary depending on the cattle, the environmental conditions, and the level and duration of the exposure. Early clinical signs are often reversible after removal from contaminated pastures or hay.