Changes in calves and rats consuming milk from cows fed chronic lethal doses of Senecio jacobaea (tansy ragwort).

Chronic lethal doses of Senecio jacobaea, which contains 6 pyrrolizidine alkaloids, were fed to 6 cows close to parturition. Their calves were allowed to suckle for 40 to 126 days to determine whether pyrrolizidine alkaloids or their toxic metabolites had been passed into the cow's milk. Histopathologic changes were not detected in the calves consuming the milk; however, clinical chemical tests suggested the presence of hepatic biochemical lesions. Rats gavaged daily for 30 days with milk from Senecio-fed cows were not grossly or histopathologically affected.