Intoxicação espontânea por brotos de Xanthium spp. em bovinos no sul do Rio Grande do Sul / Spontaneous poisoning by sprouts of Xanthium spp. in cattle in southern Rio Grande do Sul

ABSTRACT

Background: Xanthium spp., the cockleburs, are invasive plants found on riverbanks, lakeshores, and floodplains. Ingestion of Xanthium sprouts or fruit causes cocklebur toxicosis, which is characterized clinically and pathologically by acuteliver failure. The main lesion observed is an accentuation of the lobular pattern of the liver (nutmeg appearance), whichis microscopically characterized by coagulation necrosis in the centrilobular region, hepatocyte degeneration in otherregions of the hepatic parenchyma, and sinusoidal congestion. The objective of this study was to describe an outbreak ofspontaneous cattle poisoning by ingestion of Xanthium spp. sprouts in the southern region of Rio Grande do Sul, Brazil.Case In September 2018, a beef cattle farm located in Rio Grande county, Rio Grande do Sul, Brazil, reported significantmortality of cattle in a short period of time. There were 700 cattle on the property, divided by class into three differentherds, all kept under extensive conditions in native wetlands. All fields were heavily infested by cocklebur, with mostplants in the budding stage. Twenty animals developed muscle tremors, salivation, aggression, and recumbency. Theclinical course lasted 24 to 48 h, with a lethal outcome in all cases. An 18-month-old male crossbreed bovine was sent tothe Regional Diagnostic Laboratory of the Universidade Federal de Pelotas (UFPel) School of Veterinary Medicine fornecropsy. Gross examination revealed ascites and accentuation of the lobular pattern of the liver. Organ fragments wereharvested and fixed in 10% buffered formalin. Microscopically, the liver exhibited marked coagulation necrosis in thecentrilobular region and vacuolization of the hepatocyte cytoplasm in the midzonal and periportal regions. In the brain,there was perineuronal edema, cytoplasmic shrinkage and basophilia, gliosis, and satellitosis...