ABSTRACT
Fescue foot, fescue toxicosis, agalactia, and fat necrosis are four different aspects of a toxicosis observed in cattle grazing endophyte-infected tall fescue. The ultimate successful criterion for a hapten-carrier conjugate prepared as a vaccine would be an immunized animal. This chapter suggests that two specific approaches designed primarily for ameliorating fescue toxicosis, although similar approaches should apply to ryegrass toxicity and other endophyte-induced toxicities. An anti-idiotype vaccine may be necessary to overcome the effects of endophyte-infected fescue, by virtue of being able to generate high-affinity antisera. Serum prolactin is decreased in cattle grazing endophyte-infected fescue, and ergot alkaloids are potent inhibitors of prolactin secretion. Metoclopramide, a D-2 receptor antagonist, was administered to steers grazing on endophyte-infected tall fescue. The anthelmintic drug ivermectin has reduced the impact of fescue toxicosis in cattle. The symptomatology of fescue foot in cattle resembled ergot poisoning, to Cunningham, without evidence of an ergot alkaloid intake.
