Persistence of detectable residues of penicillin and cloxacillin in normal and mastitic quarters following intramammary infusion

The excretion rates of sodium penicillin and sodium cloxacillin from treated and untreated quarters of normal and mastitic cows were studied. Penicillin was detected in normal and infected quarters for 72 hours after treatment. Cloxacillin was detected in normal and infected quarters for 64 and 48 hours, respectively, after treatment. Differences in the excretion rates of both antibiotics from normal and infected treated quarters were not significant. Penicillin was detected in the untreated quarters of both normal and mastitic cows but cloxacillin was only detected in the untreated quarters of mastitic cows.