Spontaneous and experimental intoxication of cattle by Simarouba versicolor A. St.-Hill (Simaroubaceae).

This study describes an outbreak of Simarouba versicolor intoxication in cattle from Mato Grosso do Sul, Brazil, and reproduces it experimentally. Clinical signs of the affected animals were weakness, tremors, hind limbs incoordination, reluctance to move, sternal and lateral recumbency and death. The main necropsy findings, observed in the abomasum and in segments of the small and large intestines, were diffuse redness and mucosal and serosal swelling. Histological examination revealed necrosis of lymphoid tissues and necrotizing enterocolitis. One experiment was carried out using 3 male calves to test the toxicity of a single dose of S. versicolor leaves at 15 g/kg, 5 g/kg and 2.5 g/kg. Clinical signs, necropsy findings and histological examination of calves receiving 15 g/kg and 5 g/kg leaves were similar to those of cattle from the intoxication outbreak. The calf fed 2.5 g/kg leaves developed clinical symptoms of poisoning and recovered naturally. In a second experiment, two male calves received daily administration of S. versicolor leaves at 1.5 g/kg and 2.5 g/kg for 10 days. They developed clinical signs of intoxication within 24 h and recovered eight to nine days after the leaves were administered. These findings suggest that S. versicolor was responsible for the outbreak studied, although this plant does not have cumulative intoxication effects on cattle.