Economic losses due to Vernonia rubricaulis poisoning in cattle / Perdas econômicas causadas pela intoxicação por Vernonia rubricaulis em bovinos

Vernonia rubricaulis is a hepatotoxic plant found in the Pantanal biome. Under natural conditions, it is responsible for highly fatal poisonings in cattle. From January 1999 to December 2016, 33 outbreaks of V. rubricaulis poisoning were recorded, resulting in 1509 bovine deaths, of which 719 (47.6%) were adult females, 413 (27.4%) were adult males, 244 (16.2%) adult cattle with no information about sex and 133 (8.8%) calves. The coefficients of morbidity, mortality and lethality were respectively 2.79%, 2.77% and 99.24%. Most outbreaks occurred in properties containing up to 1,000 cattle, where the most significant economic impacts were also observed. Among the total recorded deaths, the total direct monetary loss was estimated at US$764,893.33, which represents an average of 3.05% of the total assets (US$25,090,683.51) of the herds involved in the outbreaks. The plant can cause more severe damage to properties with less than 500 cattle, and can reach 50% of the total value of the herd. In comparison to other methods, the methodology used in this study has an economic impact consistent with reality, not overestimating the losses. Toxic plants, such as V. rubricaulis, can cause significant economic losses in the extensive systemic livestock, and it is important decision-making and prophylactic management to avoid the occurrence of poisoning in the herds.(AU)

Vernonia rubricaulis é uma planta hepatotóxica encontrada no bioma Pantanal. Em condições naturais, é responsável por intoxicações altamente fatais em bovinos. De janeiro de 1999 a dezembro de 2016, foram registrados 33 surtos de intoxicação por V. rubricaulis em bovinos que resultaram em 1509 mortes, sendo 719 (47,6%) fêmeas adultas, 413 (27,4%) machos adultos, 244 (16,2%) bovinos adultos sem informação sobre o sexo e 133 (8,8%) bezerros. Os coeficientes de morbidade, mortalidade e letalidade foram respectivamente de 2,79%, 2,77% e 99,24%. A maioria dos surtos ocorreu em propriedades contendo até mil bovinos, onde também foram constatados os impactos econômicos mais significativos. Do total das mortes registradas, o prejuízo monetário direto total foi calculado em US$764.893,33, o que representa em média 3,05% do total do patrimônio (US$25.090.683,51) dos rebanhos envolvidos nos surtos. A planta pode causar prejuízos mais severos em propriedades com menos de 500 bovinos, podendo chegar a 50% do total do valor do rebanho. Em comparação aos outros métodos, a metodologia utilizada neste estudo afere um impacto econômico condizente com a realidade, não superestimando os prejuízos. Plantas tóxicas, como a V. rubricaulis, podem causar prejuízos econômicos significativos na pecuária extensiva, sendo importantes tomadas de decisões e manejos profiláticos para evitar a ocorrência de intoxicação nos rebanhos.(AU)

Experimental poisoning by Vernonia rubricaulis in sheep.

In order to evaluate the susceptibility of sheep to V. rubricaulis and to establish the clinical signs, serum biochemistry, and pathological findings, eight sheep were fed varying doses of V. rubricaulis. The onset of clinical signs occurred 6-48 h after the ingestion of V. rubricaulis. Clinical courses lasted 6-56 h after the ingestion of the plant. Serum activities of aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase were highly elevated and glucose blood levels were low in affected sheep. Clinical signs consisted of apathy, anorexia, dry muzzle, respiratory distress, abdominal pain, and mushy feces with streaks of blood and mucus. Two sheep had neurological signs including muscle fasciculation, nystagmus, paddling movements, and blindness. Liver necrosis could be detected antemortem through liver biopsy. Five sheep died and three recovered. The liver was affected in all necropsied sheep; it increased in volume and had marked accentuation of the lobular pattern with red, depressed areas intercalated with a pale yellow network. Ascites and hydropericardium were consistent findings. Microscopically, centrilobular to massive coagulative necrosis was observed. Coagulative necrosis was also observed in a few proximal renal tubules. Microscopic lesions were not found in any other organs. The severity of liver lesions was proportional to the dose. Chemical analysis to detect carboxyatractyloside in V. rubricaulis plant material was negative. It is concluded that V. rubricaulis poisoning in sheep is clinically, biochemically, and pathologically characteristic of an acute hepatoxicosis.

Poisoning of sheep by Vernonia plantaginoides (Less.) Hieron in Uruguay.

Vernonia plantaginoides (Less.) Hieron, previously known as Vernonia squarrosa, is a rhizomatous subshrub with purple flowers that is prevalent in the natural grassland of Uruguay, Argentina, and southern Brazil. We report an outbreak of V. plantaginoides (yuyo moro) intoxication in sheep in Treinta y Tres Department, northeastern Uruguay. A total of 54 of 463 (12%) recently weaned lambs died 2-7 days after entering a natural pasture that had been invaded by sprouting V. plantaginoides The first cases were found dead. Affected lambs showed marked jaundice, edema of the face, ears, and eyelids, and severe photodermatitis. At the autopsies of 3 lambs, the carcass was yellow, the liver was enlarged with a marked acinar pattern ("nutmeg liver"), and hemorrhages were observed on serous membranes. Microscopic lesions were characterized by diffuse periacinar hepatocellular necrosis and cholemic nephrosis. Three female lambs were experimentally dosed with the aerial parts of V. plantaginoides collected immediately after the outbreak. The lamb that was dosed once with 40 g/kg body weight died after 36 h with severe hepatic necrosis. The lamb dosed with 20 g/kg daily for 4 days showed clinical signs and microscopic lesions in the liver with multiple apoptotic hepatocytes in the periacinar zone. The third lamb, dosed with 30, 17, and 15 g/kg daily over 3 days, respectively, showed transient clinical signs and a rise in liver enzymes, but recovered, and no lesions were found postmortem. These results demonstrate that V. plantaginoides was responsible for severe field outbreaks of poisoning in sheep in Uruguay.