COMPARISON OF DISEASE IN CALVES DOSED ORALLY WITH OAK OR COMMERCIAL TANNIC-ACID

Commercial tannic acid has been used as a substitute for leaves and ac orns in studies of oak toxicosis in some species. The toxicity of a co mmercial tannic acid given orally to calves was determined, and the cl inical signs, laboratory findings, and pyrogallol production were comp ared with those found in calves dosed orally with oak leaves. The oak- fed calves developed the clinical signs and lesions characteristic of renal failure. Proteinuria developed by 48 hours in 1 calf and by 72 h ours in the other calf. Both calves developed hematuria on day 4 and g lucosuria on day 5. The blood urea nitrogen and creatinine values incr eased markedly on day 6. Pyrogallol was detected in the serum only at 3 and 6 hours after the calves began ingesting the oak leaves. Pyrogal lol was detected in urine from 1 calf until 60 hours and in the other calf until 48 hours after the beginning of oak intake. The 2 calves th at were dosed with tannic acid at the same level as found in the leave s fed to the other calves did not develop clinical signs, abnormal lab oratory findings, or pyrogallol production. Calves given high levels o f tannic acid at doses of 4.4-5.5 g/kg developed methemoglobinemia rat her than renal disease. Therefore, commercial tannic acid given orally cannot be used as a substitute for oak in studies of toxicosis in cat tle.