Pharmacodynamics of isoflupredone acetate in an endotoxin-induced mastitis model.

The effect of intravenous administration of the steroidal drug isoflupredone acetate on lactating dairy cows with mastitis induced using gram-negative bacterial endotoxin was investigated. Cows were randomly assigned to one of four treatment groups: untreated controls, isoflupredone acetate only, mastitis only, and mastitis plus isoflupredone acetate. Isoflupredone acetate was given to treated groups at a dose of 20 mg intravenously, once. Mastitic cows receiving treatment were given isoflupredone acetate after the development of clinical signs. When compared with untreated mastitic controls, cows with endotoxin-induced mastitis treated with isoflupredone acetate did not exhibit measurable differences in heart rate, rectal temperature, rumen motility, or changes in mammary gland surface area in the 14 h following the administration of intramammary endotoxin. Healthy cows treated with isoflupredone acetate had a higher heart rate over the 14 h after drug administration than did untreated healthy controls. When compared with untreated mastitic controls, cows treated with isoflupredone acetate did not exhibit statistically significant differences in milk production following endotoxin-induced mastitis.