Abstract: | Hemostatic parameters in 5 Thoroughbreds which had recently displayed post-exercise epistaxis, and 4 normal horses, were assessed using blood samples taken when the animals were at rest, immediately before exercise, and 5 minutes after galloping 1.2. km at maximum speed. Exercise resulted in marked depression in the adenosine diphosphate (ADP)-induced aggregation response of platelets from both groups of horses. No significant differences were detected when comparing the results from each group. However, there was a tendency for the platelets from the bleeder group to be less responsive to ADP. Because not all aspects of platelet function were studied the possible role of platelet abnormalities in the pathogenesis of exercise-induced pulmonary hemorrhage could not be completely discounted. |