Comparative clinical pharmacology of amikacin and kanamycin in dairy calves.

The in vitro susceptibility of Escherichia coli, Salmonella sp, Pasteurella multocida, and Pseudomonas aeruginosa strains isolated from young calves and their environment to kanamycin and its semisynthetic derivative--amikacin, was compared by the tube dilution method. The minimal inhibitory concentration of amikacin was two- to fourfold lower than the minimal inhibitory concentration of kanamycin for the Salmonella group B, Ps aeruginosa and P multocida strains examined, whereas the E coli and Salmonella group D strains were eqaully susceptible to the 2 antibiotics. The concentrations of amikacin and kanamycin in the serum of calves after single intramuscular injections at 10, 25, and 50 mg/kg were determined, and differences between the 2 antibiotics were not observed. Intramuscular dosage schedules were calculated, based on the sensitivity of the different bacterial strains and the duration of effective serum drug concentrations.