This paper reports cattle mortalities in the states of Mato Grosso and Mato Grosso do Sul, Brazil, caused by the consumption of the leaves of Pterodon emarginatus. The outbreaks occurred during the dry season after P. emarginatus trees had fallen to the ground due to high winds or after having been cut for wood, and cattle had access to the branches. Forty cattle died during three different outbreaks. First clinical signs were seen after 24-72 hours of the consumption of the leaves by the cattle. The course of the letal disease was from 12 to 36 hours. Clinical signs were characterized by apathy, depression, walking aimlessly, pressing the head against objects, and occasionally photosensitization in cases of poisoning with a longer clinical course. The disease was reproduced by administration of P. emarginatus leaves at a minimum toxic dose of 20g/kg for sheep and 6g/kg for cattle. The main macroscopic findings in spontaneous and experimental cases were in the liver, characterized by hepatomegaly and diffuse accentuation of the lobular pattern on the capsular and cut surfaces. Additionally, there were petechiae, ecchymoses and suffusions within the thoracic and abdominal serosa surfaces. In two outbreaks, fotossensibilization was reported in cattle that survived the acute phase. The main histopathological findings were marked centrilobular or massive coagulative hepatocellular necrosis associated with congestion and hemorrhages, surrounded or not by markedly swollen and vesicular hepatocytes in the periacinar area. The diagnosis was based on epidemiological data, clinical signs, necropsy findings, histological lesions and experimental reproduction of the poisoning in cattle and sheep. These findings showed P. emarginatus to be a hepatotoxic plant of interest in the Midwest region of Brazil.
Poisonous plants; Pterodon emarginatus; Fabaceae Faboideae; plant poisoning; cattle; sheep
