Tall fescue (Festuca arundinacea ) is one of the most abundant cool-season grasses in the southeastern United States, occupying over 35 million acres of land. 62% of the grasses on this land are infested with the endophyte fungus, Neotyphodium coenophialum. N. coenophialum lives within the plants and seeds and produces varying amounts of ergot alkaloids. Cattle are very sensitive to ergot alkaloids, and become poisoned over time through consumption of the endophyte-infected grass or hay. The principal alkaloid responsible is ergovaline; the amount present in the plant varies considerably depending on the strain, plant part, stage of maturity, environmental conditions, and geographic region.