Personal interviews of horse owners and veterinarians and clinical research have revealed that many horses exhibit most of the signs of fescue toxicosis while consuming even small quantities in hay, small patches of E+ fescue in paddocks, or even by grazing a small quantity of E+ fescue under paddock fences (Cross et al., 1999). Therefore, to prevent toxicosis in horses, E+ tall fescue must be eliminated completely in pastures. Personal experience and interviews with livestock owners and managers throughout the United States attest to the extreme difficulty of eliminating E+ fescue from pastures. Experience has shown that unless pastures are completely devoid of E+ plants and viable seed, E+ plants become significant problems within 1 to 3 yr after replanting pastures. Best success with pasture reseeding (see Chapter 5) has come through the use of chemical destruction of the fescue or an intense fallow followed by crops that have a dense canopy for 2 yr before reseeding to another pasture forage. Establishment of clover or other forage mixtures with E+ fescue seems to be a reasonable alternative for cattle (see Chapter 6 and Chapter 7), but not for horses.