Pharmacokinetic parameters of the disposition of oxytetracycline (OTC) were investigated in healthy cycling dairy cows after a single i.v. dose of 22 mg/kg of body wt. The biological half-life of OTC was 6.5 h. These data were used to predict an i.v. priming dose and a rate of constant i.v. infusion of OTC sufficient to approach steady-state equilibrium of the drug between a plasma concentration of .apprx. 5 .mu.g/ml and a uterine tissue concentration. After 8 h constant i.v. infusion, the mean plasma concentration of OTC was 4.86 .+-. 0.68 .mu.g/ml and the mean uterine tissue concentration of OTC was 4.50 .+-. 0.45 .mu.g/ml. The mean ratio of plasma-to-uterine tissue OTC concentrations was 1.08. Computer-simulated i.v. multiple doses of OTC at 11 mg/kg every 12 h and 11 mg/kg every 24 h suggested that the former dosage regimen could provide uterine tissue concentrations > 5 .mu.g/ml during the dosage interval, whereas the latter could provide such concentrations for only the first 12 h of a 24-h dosage interval.