Polioencephalomalacia was induced in eight buffalo calves, 6-12 months old, by drenching
amprolium (300 mg/kg
body weight per day) for 29-55 days. Four buffalo calves of the same age group were drenched with tap water only and served as control. Blood samples were collected at different intervals during
amprolium administration until the onset of clinical signs. Cerebrospinal fluid was also collected prior to
amprolium administration and at the onset of clinical signs. A significant progressive decrease in erythrocyte
transketolase (TK) activity and an increase in the percent of
thiamine pyrophosphate (TPP) effect were observed in
amprolium-fed calves during
amprolium administration until the onset of clinical signs. There was a significant increase in blood
lactate and blood
pyruvate concentrations and a significant decrease in
lactate/
pyruvate ratio at the onset of clinical signs. Serum
electrolyte (Na, Ca, P, Mg) concentrations showed no significant changes. However, the serum
potassium concentration had decreased significantly at the onset of signs. The cerebrospinal fluid analyses revealed a significant increase in
lactate and
pyruvate concentrations and
lactate/
pyruvate ratio in
amprolium-fed calves. The
electrolytes (Na, K, Ca, P and Mg) of cerebrospinal fluid did not show any change. It is concluded that
oral administration of
amprolium (300 mg/kg
body weight daily) for 4-6 weeks produces biochemical changes characteristic of polioencephalomalacia in buffalo calves.