The ingestion of Senecio spp. (ragwort) is perhaps the leading cause of death of cattle in central and southern Rio Grande do Sul, Brazil. Considering the limited information about this condition in the Western region of Rio Grande do Sul, Brazil, this paper describes main epidemiological clinical and pathological aspects of seneciosis in cattle. The assessments were made through questionnaires on 16 rural properties which had suspected cases of poisoning in cattle, from August 2011 to March 2014. During the visits were evaluated epidemiological aspects of poisoning and performed sample collection of Senecio plants for botanical identification, as well as collection of liver samples using transthoracic biopsy for confirmation of the poisoning. Senecio species most common on farms were S. brasiliensis and S. heterotrichius. From 88 cattle that failed to thrive on nine different farms, 69 animals (about 80%) were positive for chronic seneciosis with periportal fibrosis (78% of cases), megalocytosis (76% of cases) and with bile duct proliferation (68% of cases). Lesions were classified as mild, moderate or marked. The current study confirms the occurrence of this poisoning, even in cattle without evident clinical signs. The use of liver biopsy enabled the early diagnosis of poisoning and helped farmers carefully to dispose affectd cattle, as well as to recognize the real situation of poisoning in the herd and minimize economic losses.
Poisonous plants; diseases of cattle; chronic hepatopathy; pyrrolizidine alkaloids; plant poisoning; pathology; toxicoses