Effects of fumonisin-contaminated corn screenings on growth and health of feeder calves.

Fumonisins are myocotoxins produced by Fusarium moniliforme and F. proliferatum, common molds of corn in North America. The toxin is at especially high concentrations in corn screenings. Fumonisins are toxic to swine and horses, but effects of these toxins in cattle have not been evaluated. This experiment was conducted to determine the effects in cattle of feeding fumonisins at levels known to be toxic to swine and horses. A total of 18 crossbred feeder calves were fed diets containing fumonisins at 15, 31, or 148 micrograms/g for 31 d. Feed consumption, weight gain, complete blood count, serum clinical chemistries, and an immune function profile were done on d -3, 4, 10, 17 and 31 relative to the start of fumonisin feeding. There was no treatment-related effect on feed intake or weight gain, but feed containing 148 micrograms/g of fumonisins seemed to be less palatable than other feeds. Significant increases in serum aspartate amino transferase, gamma glutamyl transpeptidase, lactate dehydrogenase, bilirubin, and cholesterol occurred from d 10 through 31. Mild microscopic liver lesions were present in two calves fed at the highest fumonisin level. Lymphocyte blastogenesis was significantly impaired at the end of the feeding period in the group given the highest dose. Other measures of immune function were not affected significantly. Fumonisins are capable of causing changes in liver function and in some measures of immune function. However, cattle seem to be relatively less susceptible to fumonisins present naturally in grains than either swine or horses.