Senecio pampeanus poisoning in beef cattle: case report and toxicological evaluation.

Pyrrolizidine alkaloidosis occurs sporadically in cattle in South America, associated with the consumption of several Senecio species including S. brasiliensis, S. grisebachii, S. madagascariensis, S. oxyphyllus and S. selloi. Although S. pampeanus has been potentially reported as hepatotoxic, there is no scientific evidence of outbreaks associated with its consumption. This report describes a case of chronic hepatotoxicity in a beef heifer in Buenos Aires province in Argentina, grazing native grasslands heavily infested with S. pampeanus. Clinical and pathological findings were consistent with pyrrolizidine alkaloidosis, including hepatic fibrosis, marked hyperplasia of the bile ducts and the presence of abundant hepatomegalocytes. Furthermore, four unsaturated pyrrolizidine alkaloids (PAs) were identified in S. pampeanus including florosenine, doronine, otosenine and desacetyldoronine. Some clinical and histological details are suggestive of a chronic, low-dose pyrrolizidine alkaloidosis probably associated with the low concentration of toxic principles found in S. pampeanus. Further studies are needed to know PAs variation in S. pampeanus and its potential dissemination throughout the region, implying an important risk for livestock.