Serum oxytetracycline concentrations in African elephant (Loxodonta africana) calves after long-acting formulation injection

Serum oxytetracycline pharmacokinetics were studied in 18 African elephant (Loxodonta africana) calves. Each elephant received separate injections of oxytetracycline at approximately 18 mg/kg i.m. and 8 mg/kg i.v. in a cross- over study. Blood samples were drawn at 0, 24, 48, 72, and 96 hr postinject ion. An additional sample was drawn 110 hr before the animals were reinject ed in the cross-over study and a final blood sample was drawn 48 hr after t he second dose. No lameness or stiffness was observed following i.m. inject ions. Serum oxytetracycline concentrations >0.5 mu g/ml were present 48 hr after initial dosing for all elephants (i.m., i.v., high or low dosage). On ly elephants given the high i.m. dosage (18 mg/kg) maintained levels >0.5 m u g/ml 72 hr postinjection. No significant difference in serum oxytetracycl ine concentration with time was observed between the groups given different i.v. dosages. These studies demonstrated that quantifiable serum oxytetrac ycline concentrations can be maintained in young African elephants with a l ow-dosage multidose i.m. regimen.