Oxytetracycline-containing bovine serum albumin microspheres for treatment of calves with experimentally induced Pasteurella haemolytica pneumonia

Heat denatured bovine serum albumin microspheres containing oxytetracycline (BSA-OTC MS) were injected into the jugular veins of calves with experimentally induced Pasteurella haemolytica pneumonia. Serum levels of oxytetracycline in the traditional treatment group fell in the expected range (1-10 μg/ml); serum levels of drug in the groups administered BSA-OTC MS were below detection limits of the test (< 0.5 μg/ml). Clinical results using BSA-OTC MS administered daily at 12.5% of normal whole body drug dose, but targeted to the lung by size, yielded equivalent outcomes to a standard OTC intravenous dosing regimen. Clinical results for a single dose of BSA-OTC MS were largely indistinguishable from the negative control group, which received no treatment.