Impact of the Endophyte on Animal Production

Tall fescue is productive and well adapted to the soils and climate in a region commonly referred to as the “fescue belt”, which overlays the transition zone between the temperate northeast and subtropical southeast. Persistence of the grass under low input management is attributed to a fungal endophyte that infects most fescue plants and produces alkaloids that impart tolerance to heat, drought, and grazing stresses. Unfortunately, the endophyte also produces ergot alkaloids that can induce toxicosis. Signs of “fescue toxicosis” are elevated body temperature and respiration rate, retention of winter hair coats through the summer months, hormonal imbalances, and reduction in dry matter (DM) intake (Strickland et al., 1993). Consequently, ingested ergot alkaloids adversely affect calf growth rates, conception and pregnancy rates, and milk production (Porter and Thompson, 1992).