Disposition kinetics and dosage of cephalexin in cow calves following intramuscular administration.

Cephalexin was administered im to cow calves at a dose rate of 10 mg/kg bw. After im administration, the disposition kinetics of cephalexin followed a 1-compartment open model. The values of elimination half-life, volume of distribution and total body clearance were 2.00 +/- 0.13 h, 0.32 +/- 0.02 l/kg and 1.899 +/- 0.199 ml/kg/min, respectively. 58.8% of cephalexin administered was recovered in the urine within 24 h. A satisfactory intramuscular dosage regimen of cephalexin in cow calves would be 15 mg/kg administered at 9-h intervals.