When significant quantities of B1 are consumed, the metabolite M1 appears in milk within 12 hours. M1 aflatoxin is not as carcinogenic as B1 but is toxic to humans. Aflatoxin M2 is also present in milk. Dairy and beef cattle are more susceptible to aflatoxins than sheep and horses. Young animals are more susceptible than mature animals with pregnant and growing animals intermediate in susceptibility.
Aflatoxins affect organs such as the liver, kidney, heart, and adrenal glands.
Symptoms include feed refusal, reduced growth rate, decreased feed efficiency, and decreased milk production. In addition, listlessness, weight loss, rough hair coat, mild diarrhea, anemia with bruises and subcutaneous hemorrhage, impaired immune system response, increased susceptibility to disease, and rectal prolapse may be observed. The severity of aflatoxicosis varies with the animal species, level of aflatoxin in the diet, and the duration of exposure to aflatoxin. The diagnosis of aflatoxin poisoning is difficult because of the variations seen between animals and farms, but liver damage is a common observation. Aflatoxins cause the liver to become pale tan, yellow or orange.