Ph.D. OSU Extension Dairy Specialist David L. Lalman, Ph.D. OSU Extension Beef Cattle Specialist Introduction Aflatoxins are a group of highly toxic compounds produced by the molds Aspergillus flavus , A. parasiticus and A. nomis which when ingested by livestock can result in increased disease and reduced production efficiency. The resulting symptoms mimic those of other metabolic and infectious diseases, including ketosis, Johne's, Bovine Viral Diarrhea, Salmonella and clostridial infections, and some poisonous weeds, making diagnosis difficult. To further complicate matters, molds may be growing actively without mycotoxin formation, and mycotoxins may be present even though mold growth is not readily evident. Therefore, appearance of the feed and presence of mold are also poor indicators of the potential for mycotoxicosis in livestock.
Aflatoxins can invade feedstuffs at any point from field to feedbunk.
Although some feeds may be more prone to aflatoxin contamination, grains, by-product feeds, protein concentrates, finished feeds, oilseeds, food wastes and forages may become infected. The severity of aflatoxin contamination of feeds is determined by environmental factors such as excessive moisture in the field and in storage, temperature extremes, humidity, drought, and variations in harvesting practices and insect infestation. In the southern U.S., drought occurring during the latter part of the growing season appears to be the single most significant factor in crops where field infection has occurred. Beside the negative effects on livestock production efficiency, aflatoxin contamination of feed is of particular concern to producers since it is a recognized carcinogen and major efforts are directed at eliminating its residue in food. The Food and Drug Administration is responsible for regulating aflatoxin levels in food and feed.