Poisoning occurs when over half the diet is oak buds and young leaves, or acorns, for a period of time. Livestock have also been poisoned by drinking water in which oak leaves have soaked. Plant tannins or their metabolites cause gastrointestinal and renal dysfunction. Symptoms appear several days after the period of consumption and include abdominal pains, weakness, anorexia, colic, constipation, depression, diarrhea, presence of blood in urine, and jaundice. Death may result.
Horses are less susceptible than ruminants.
Oak poisoning resembles pigweed poisoning. The Ohio buckeye is widely distributed throughout the state, while sweet buckeye is confined to southern Ohio. Sprouts and leaves produced in early spring and seeds are especially poisonous. However, experimental feedings have shown that poisoning does not always follow buckeye consumption. Affected animals exhibit depression, incoordination, twitching, paralysis, inflammation of mucous membranes, and vomiting.