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Three calves were dosed orally with carbon tetrachloride at 0.05, 0.1 or 0.3 ml/kg body-weight. Plasma enzyme activities, clotting times, bilirubin concentrations and bromsulphthalein elimination times increased. These changes are associated with damage to the liver and are discussed in relation to the clinical syndrome. Three groups of seven calves were infected weekly with 10, 50 or 100 Fasciola hepatica metacercariae for 12 consecutive weeks. Maximum glutamate dehydrogenase and gamma glutamyltransferase activities in the plasma were greater with the larger infecting doses but there was no change in plasma clotting times.

Four groups of six 12-week-old male Friesian calves were fed diets containing 390 to 540 microgram ochratoxin A per kg, 320 to 500 microgram ochratoxin A plus 12 to 13 microgram aflatoxin B1 per kg, 10 to 13 microgram aflatoxin B1 per kg, or a control diet containing neither toxin. At the end of the 87-day experiment there was no evidence of kidney or liver damage in any group of animals as judged by serial plasma and urine enzyme assays, haematological examinations including the assay of blood coagulation factors, gross appearance at autopsy or histopathological assessment at the light microscopic level. Nor was there any significant alteration in serum IgA, IgM, IgG1 and IgG2 levels or in titres to environmental bacterial and viral antigens. Trace amounts of ochratoxin A were detected in kidneys of five out of the 12 calves exposed to this toxin but all 12 kidneys contained residues of the metabolite ochratoxin alpha (less than 5 to 10 microgram/kg). Traces of aflatoxin B1 and M1 were detected in the liver of one of the 12 calves exposed to aflatoxin B1 but nine kidneys contained the metabolite aflatoxin M1 (less than 0.01 to 0.03 microgram/kg). There was no evidence of interaction between the two toxins.