Case of Suspected Wintersweet (Chimonanthus Praecox ) Toxicity in Corriedale Sheep

Abstract

In August 2016, two grazing sheep (Corydale, 4 years old, female) were unable to stand independently, presenting with symptoms of tonic-clonic seizure and dyspnea. The blood examination results showed a marked increase in AST, ALP, CPK, GGT and LDH, an increase in total bilirubin concentration, and hypocalcemia. In the necropsy, pieces of black seeds were observed in the filtrated rumen content, which were identified as wintersweet (Chimonanthus praecox ) through genetic testing. Wintersweet seeds contain calikantin, a kind of alkaloid, and when consumed by animals, it causes nervous symptoms due to GABA inhibitory action. In addition, because a typhoon passed by the day before the onset of the symptoms, many wintersweet seeds had fallen into the pasture. Therefore, the case was considered to be toxicosis in sheep caused by the ingestion of wintersweet seeds, which was reported for the first time in Japan.