Suspected acorn poisoning in a donkey - a case report

Oak trees, specifically their bark, leaves and acorns, are rich in gallotannins and a common source of poisoning when ingested by livestock and horses. Gallotannins denature protein and thus are capable of damaging the intestine and impairing digestion. As a result, many susceptible species, like cattle, sheep and equids, develop haemorrhagic diarrhoea. The main gallotannin metabolites are absorbed and may cause kidney and liver failure. It is assumed that gallotannins are also toxic for donkeys, despite a lack of reports in the scientific literature. Symptoms are reportedly comparable to those seen in horses. This case report describes the clinical signs, laboratory findings, treatment and outcome of a donkey with highly suspected acorn poisoning and highlights the differences between donkeys and other species. A twelve-year-old donkey was admitted to the Equine Clinic Altforweiler, Uberherrn-Altforweiler, Germany, in October, with lethargy, inappetence, slight incoordination and ptyalism. The donkey had been observed eating acorns on the previous day. The patient subsequently developed paralytic ileus and azotaemia. Acorn poisoning was considered a differential diagnosis as alimentary and/or renal disorders typically develop following gallotanin intoxication in other susceptible species. The donkey received non-specific supportive therapy including gastric lavage, intravenous fluid therapy, analgesia and anti-endotoxaemic medication. Once the donkey was no longer producing reflux, liquid paraffin and sucralfate were added to the treatment regimen. The patient improved following 24 hours of intensive therapy and recovered completely after four days at the clinic.