Relationship between uterine pathology and depletion of oxytetracycline concentrations in plasma and milk after intrauterine infusion

Abstract

Up to 90% of dairy cows develop bacterial contamination of the uterus during the first week after calving. Intrauterine treatment with antimicrobials is commonly practiced on dairy farms, even though studies demonstrating improved reproductive performance after treatment are lacking. Intrauterine infusion of antimicrobials can result in costly milk discard, and increases the risk for antimicrobial residue in bulk-tank milk intended for human consumption. Because there are currently no antimicrobials approved for intrauterine administration in cattle, the veterinarian is primarily responsible for ensuring that milk from treated cows is free from antimicrobial residues. Results of previous trials have indicated considerable variation in the depletion profile of drugs after intrauterine infusion. For this study, we hypothesized that the variability in the elimination of oxytetracycline in milk is associated with the extent of uterine pathology among cases.