This could have significant implications in cases in which veterinarians prescribe aspirin to treat diseases with increased platelet activation, such as endotoxemia or laminitis. | Photo: iStock

“Based on my data and that of others in previous published studies, there is probably less anticoagulatory efficacy of aspirin in horses,” said Katja Roscher, DrMedVet, Dipl. ECEIM, of the Justus Liebig University Department of Veterinary Clinical Science Equine Clinic, in Giessen, Germany.

In their study, Roscher and her fellow researchers tested how a five-day aspirin treatment affected coagulation (blood clotting) properties in 10 horses. They gave the horses a loading dose (4.7-5 mg/kg) orally the first morning and a maintenance dose (1-1.3 mg/kg) every day for the following four days.

Seven horses initially showed a marked reduction in platelet aggregation (clotting), ranging from a 37% to 100% reduction only six to 12 hours after the loading dose, Roscher said. But over the next four days, the researchers saw much less reduction, with a lot of variation from horse to horse, ranging from 0% to