Mycotoxins in Forages and Their Impact on Animal Health

Abstract

Moldy and damaged forages occur commonly and are widely fed to ruminants. Major mycotoxins associated with forages include the endophyticfungi responsible for fescue toxicosis, the tremorgens, slaframine associated with red clover, stachybotryotoxin in straw, sporodesmin, and ergot alkaloids from the grasses. Effects from forage associated mycotoxins are seldom acutely fatal, but cause effects including reduced gain, lowered milk production, peripheral gangrene, ataxia and tremors, excessive salivation, gastroenteritis, photosensitization and dermal necrosis. Clinical effects can mimic other common disease conditions and diagnosis depends on thorough review of history and circumstances as well as clinical and laboratory evaluation. Currently, analytical tests are used to confirm presence of the toxins, but are not routinely available on a routine basis. Common feed grain mycotoxins (aflatoxin, zearalenone, trichothecenes) are occasionally reported from forages, but generally are not a clinical or production problem associated with forages. Most of the forages related mycotoxins are associated with well defined climatic, weather and cultural conditions; thus often can be avoided by appropriate cultural and management practices. Prevention is the key to reducing losses since specific effective antidotes are not available.