The kidneys exhibited intense congestion of glomerular capillaries, small hemorrhagic foci in the medullary region, and discrete vacuolar degeneration of the proximal convoluted tubules epithelium. The heart showed severe bleeding in the endocardium, extending to the myocardium. Meningeal and

parenchyma blood vessel congestion and small hemorrhagic foci were observed in the central nervous system (CNS). Calves 1 and 2, which received a single selleck inhibitor S. versicolor dose in Experiment 1, fell sick 4 and 21 h after plant administration, respectively. The clinical signs, which were similar between the animals, included apathy, mucosal congestion, loss of appetite, diarrhea with watery, green and fetid stools, lateral recumbency and abdominal breathing. The main necropsy findings were intense and diffuse redness of the abomasal mucosa and the serosal and mucosal layers of the intestine, which contained bloody substance. The mesenteric lymph nodes were enlarged, with surface depressions, and hemorrhage

areas; mesenteric vessels were markedly engorged. Calf 3 was apathetic, with hyperemic mucosa, loss of appetite, diarrhea with watery, green and fetid stools and polydipsia, but showed clinical recovery three days after S. versicolor administration. find more In Experiment 2, calves 3 and 4 had diarrhea with watery, green and fetid stools, apathy and loss of appetite 24 h after plant administration. They recovered from the clinical signs within 8–9 days from the beginning of the plant administration in daily doses, indicating non-cumulative effects. Histological changes were similar between calves 1 and 2. They consisted of necrosis in the lymphoid tissues (spleen, lymph nodes, Peyer’s patches) (Fig. 2) and necrotizing enterocolitis (Fig. 3). No changes were found in serum biochemistry Silibinin analyses. Clinical signs, necropsy and histological findings in cattle spontaneously intoxicated by S. versicolor were similar to those found in experimentally poisoned calves, providing evidence that the plant

was responsible for the outbreak studied. Other studies do not report spontaneous or experimental poisoning of cattle or other livestock by S. versicolor leaves. However, this plant, which is locally called “estraquinina” (a type of poison) ( Lemos, 2012), is considered toxic in the Pantanal and by livestock producers in the outbreak area because it is rarely grazed ( Pott and Pott, 1994). Although the S. versicolor tree can reach 11 m in height ( Lorenzi, 1998), the ingestion occurred, in the outbreak area, because the plants were still growing and were about 1 m in height. The single doses of 15 g/kg and 5 g/kg of S. versicolor leaves were lethal to the cattle. The doses of 1.5 g/kg and 2.