Oxytetracycline is an antibiotic routinely used in an extra-label manner for intrauterine therapy.
Research supporting the efficacy of intrauterine antibiotics is minimal, yet the practice is common.
A study was performed to establish the duration of oxytetracycline residues in milk from cows with retained fetal membranes given the antimicrobial via intrauterine infusion. The study also investigated whether the number of infusions or the presence of fever affected the duration of residues. Cows were treated once a day with 5 g of oxytetracycline by intrauterine infusion for at least 2 days, or until the membranes were expelled. Milk obtained from cows that are treated for retained fetal membranes by intrauterine infusion of oxytetracycline may contain the drug for variable lengths of time. Milk should be discarded to avoid illegal residues.