Responses of Dairy Calves to Aflatoxin-Contaminated Feed

Abstract

The purpose of this experiment was to determine the aflatoxin dose relationships, the clinical biochemical changes, and the tissue effects of feeding aflatoxin to young dairy calves. Six aflatoxin dose levels, 0.008mg B1/kg body weight per day to 0.080mg B1/kg body weight per day, were fed to six pairs of young dairy calves for six weeks. Each pair of calves was fed for a six-week pretoxin and a six-week toxin feeding period. Tissue samples were examined by light microscopy for aflatoxin-induced lesions. The young calves consumed 100% of the dose up to 0.020mg B1/kg body weight per day. At higher dose levels, smaller percentages of the aflatoxin dose were consumed. Weekly body weight changes, albumin/globulin ratios, and total serum protein were not significantly affected by aflatoxin treatment. A significant (P<.01) increase in serum alkaline phosphatase values was shown at levels of 0.020mg B1/kg body weight per day or more. Gross lesions at postmortem included loss of color in the liver and adrenal hyperplasia of the aflatoxin-treated calves. Histological examination of liver tissue indicated typical early aflatoxin bile duct and central vein proliferative changes, an accumulation of fat and a corresponding loss of glycogen, along with disorganization of the liver lobules and invasion by reticular fibers.