Intoxicação espontânea por Baccharis coridifolia em cordeiros lactentes / Spontaneous Baccharis coridifolia poisoning in suckling lambs

ABSTRACT

Background: Baccharis coridifolia is one of the most important and common poisonous plants in Rio Grande do Sul (RS) state, Brazil (RS). The intoxication occurs when native livestock are exposed to the plant for the first time, especially when they are hungry, thirsty and stressed after transportation. The lesions associated with the toxicosis are characterized necrosis of the epithelial lining of the pre-stomachs. Cases of intoxication by Baccharis spp. in sheep native of a certain farm are uncommon. The objective of this study is to report an outbreak of B. coridifolia poisoning in lambs in RS, Southern Brazil, and to address the epidemiological, clinical and pathological aspects of this condition.Cases Ten 15-20 day-old Corriedale and Texel lambs from a lot of 150 were affected. The onset of clinical signs occurred two days after the lambs were moved from ryegrass (Lolium multiflorum) pasture to a native pasture with moderate amounts of sprouting B. coridifolia. Main clinical signs were intense abdominal pain, during which some lambs distended the thoracic and pelvic limbs while standing up, diarrhea, dehydration, ruminal atony, salivation, decubitus and death. Gross lesions in three necropsied lambs were mainly located in the digestive tract and included varying degrees of hyperemia, edema and erosions in the fore stomach mucosae. Histologically, there were hyperemia and degenerative, necrotic and ulcerative changes in the epithelial lining of forestomachs. The lesions observed were characterized by hydropic degeneration stratified mucosal epithelium and multifocal intercellular edema. Necrosis of individual epithelial cells, which had the intensely eosinophilic cytoplasm with a pyknotic or karyorrhetic nucleus, was observed. Multiple clefts were seen at the junction of the epithelium with the lamina propria, some of which containing intact and viable neutrophils.[...]