Understanding How to Avoid Acorn Toxicity in Horses

UNDERSTANDING HOW TO AVOID ACORN TOXICITY In horses, ingestion of acorns and oak tree parts can cause damage to their gastrointestinal (GI) or renal systems, and less frequently, liver. Most cases of poisoning occur either in the autumn when acorns have just fallen off of trees or in the spring following storms, when oak buds begin to emerge. An infographic presented by e HorseDVM * Horses turned out in pastures with poor grass cover and/or by themselves may be more likely to consume acorns due to hunger or boredom. Acorns, young buds, twigs and Tannin concentrations are highest leaves from oak trees (Quercus in green, recently fallen acorns and newly emerged, growing oak buds. species) contain hydrolyzable tannins (such as gallotannins), which are toxic to horses if ingested in sufficient quantities. Tannins interact with and prevent the absorption of protein in horses. Clinical signs Depression Loss of appetite Frequent Colic Bloody urination Diarrhea Mildly affected Severely affected Diagnosis Detection of gallotannins in GI contents or urine; evidence of acorn parts in feces. Confirmed exposure or access to oak trees and/or acorns in or around horse's turnout pasture. V Definitive diagnosis is obtained from histological findings at necropsy. Differential diagnoses Pigweed (Amaranthus) toxicity Aminoglycoside antibiotic toxicity Oxalate poisoning Treatment A prompt call to your veterinarian is needed if you suspect that your horse may have ingested sufficient quantities of parts of an oak tree or acorns. Supportive care for kidney and gastrointestinal tract damage, which will vary based on the severity; treatment usually includes fluid and electrolyte therapy for several weeks. Preventive actions Trim all reachable branches of oak Fence off horses from oak trees and Be mindful not to dispose of oak trees that are located in or beside the areas where acorns have dropped in clippings or acorns where horses can fence line of horse paddocks. pastures. access them. References Smith S, Naylor RJ, Knowles EJ, Mair TS, Cahalan SD, Fews D, Dunkel B.. Suspected acorn toxicity in nine horses. Equine Veterinary Journal. September 2015. Anderson GA, Mount ME, Vrins AA, Ziemer EL. Fatal acorn poisoning in a horse: pathologic findings and diagnostic considerations. Journal of American Medical Association. 1983. TM HorseDVM