The S. versicolor tree may reach up to 11 m in height, although in the western region of Mato Grosso do Sul most of the specimens are about 3–4 m in height. An outbreak of cattle mortality of unknown etiology, characterized by weakness, tremors, hind limbs incoordination and reluctance to move, was recorded on a farm in Água Clara, Mato Grosso do Sul, Brazil. The affected cattle were suspected

of feeding on S. versicolor, which was abundant on the property. The present study describes the epidemiology, clinical signs, necropsy and histopathological findings of spontaneous intoxication of cattle with S. versicolor and reproduces it experimentally. The outbreak was recorded on a farm with extensive livestock production in Água Clara city (20°37′05, 10″S, 52°36′01, 24″W, 303 m), learn more eastern Mato Grosso do Sul State, Brazil (BR). Epidemiological data were provided by livestock handlers interviewed during visits to the farm. Two animals were necropsied, one 12 h postmortem and the other after

clinical examination followed by euthanasia. Organ fragments were collected, fixed in 10% formaldehyde solution, subjected to routine methods and stained with hematoxylin and eosin (HE) for histological examination. The paddocks where the dead animals were found contained not only forage grass (Brachiaria decumbens and Brachiaria brizantha) but also invasive toxic plants, which were collected MEK inhibitor and submitted for botanical identification at the Botany Laboratory and kept in the Herbarium (CGMS) of the Federal University of Mato Grosso do Sul (UFMS). The species identified were S. versicolor (CGMS – 34897), Senna occidentalis, Senna obtusifolia and Crotalaria mucronata. Pasture was evaluated in terms of forage supply, i.e., areas where pasture height was lower than 10 cm were considered areas with depleted forage availability, whereas areas where pasture height was 20–40 cm were considered to contain a good forage supply (Sbrissia, 2004). To experimentally reproduce intoxication, green leaves without Selleckchem 5-Fluoracil stems of S. versicolor were collected in the paddock where the cattle died during the outbreak. The leaves were stored in

plastic bags and frozen at −5 °C. Each portion of leaves fed to the cattle was removed from the freezer 24 h before administration. Two experiments were conducted (Table 1), using four crossbred male calves aged 8–12 months. The animals weighed 121, 110, 130 and 185 kg (calves 1, 2, 3, and 4, respectively) and were held in individual stalls supplied with water, alfalfa hay and feed. The experiments were approved by the Animal Ethics Committee (CEUA) of UFMS (protocol number 400/2012). In experiment 1, three animals (calf 1, 2 and 3) were administered single leaf doses of 15 g/kg, 5 g/kg and 2.5 g/kg, respectively, to determine the toxic dosage of the plant. In calf 1, the leaves were given by rumen cannula, and for calves 2 and 3, they were administered orally.