Tall fescue is the most important forage crop in Tennessee. It is grown on approximately 3.5 million acres in the state, and is used as the base diet for nearly all beef cattle in Tennessee. An adapted strain of this grass was discovered growing on a farm in Kentucky in 1931. The cultivar "Kentucky-31" was released in the early 1940s, and was widely accepted by farmers throughout the Southeast because of its wide range of adaptation, ease of establishment and persistence.
It gained a reputation as low palatability forage that resulted in poor animal gains and various toxicosis symptoms, even though chemical analysis indicated that tall fescue was as good as any other cool-season grass. It was discovered that tall fescue was infected with an endophytic fungus (Neotyphodium coenophialum). This fungus causes toxicosis problems in the animal, but it enables the plant to better survive drought, insect and disease pressure.