Outbreaks of Brachiaria ruziziensis and Brachiaria brizantha intoxications in Brazilian experienced cattle.

Brachiaria species are some of the most used forage species for raising Brazilian cattle because of their great nutritional value and adaptability to the tropical climate. However, cases of animal intoxication have been described. Animal species, age, genetic resistance, and previous adaptation to the forage can influence the susceptibility to intoxication. Cattle (young or adults), other adult ruminants and animals adapted to consumption (experienced flocks) are considered more resistant. The main clinical presentation is that of hepatogenous photosensitization. Brachiaria brizantha and Brachiaria ruziziensis are considered less toxic. The aim of this study is to describe three outbreaks of intoxication by B. brizantha and B. ruziziensis in experienced cattle, as well as to compare the concentrations of protodioscin in paddocks with and without clinical cases. It was observed that the two forage species are toxic to all age groups of cattle adapted to their consumption, and the concentrations of protodioscin present in the plant cannot be used as the only criterion for determining the occurrence of intoxication.

Fatal lancehead pit viper (Bothrops spp.) envenomation in horses.

Snake bite envenomations in farm animals are generally overestimated as the cause of mortality in rural areas in Latin America. However, most cases are based only on anecdotal information and assumptions, and lack diagnostic evidence. There are few proven reports of envenomation and death in horses caused by snakebites from members of the Bothrops genus (lancehead pit vipers). This study presents epidemiological and clinical-pathological findings of fatal bothropic envenomation in horses from Central Western Brazil in order to contribute to the correct diagnosis of this condition. A survey of the records of equine necropsies from the Veterinary Pathology Laboratories of the University of Brasilia, Federal University of Mato Grosso and Federal University of Mato Grosso do Sul, from January 2010 to February 2018, was performed. Five fatal cases of bothropic snakebite were identified in 755 necropsies of horses, corresponding to 0.66% of these cases, ranging annually from 0.33% to 0.89%. The main necropsy findings were marked swelling and diffuse subcutaneous hemorrhage, and identification of the fang marks in 2 out of five horses. Hemorrhage in most organs and tissues was the pathological hallmark of systemic envenomation. Myonecrosis, dermonecrosis, and moderate to severe kidney degeneration and necrosis were also observed. Fatal Bothrops snakebites in horses have a low occurrence in Central Western Brazil and most cases occur in the rainy season. The diagnosis of this condition may be substantiated by clinical signs and pathological findings. Local hemorrhage and necrosis, systemic hemorrhagic disorders and injuries related to acute kidney injury are the predominant clinical signs. These findings should be considered in the diagnosis and therapeutic management of these envenomations.