Coagulation system in horses in the aspect of comparative pathology

Abstract

The coagulation system, which is responsible for maintaining an organism’s hemostasis, is present in all mammals; nevertheless, there are differences in the dynamics of processes of coagulation activation and fibrinolysis in individual species. In horses, the development of hemostasis processes is different at all stages in comparison to humans. Primary hemostasis is maintained at a relatively low number of thrombocytes with coexisting differences in the structure and morphology of blood platelets. For many years, primary hemostasis has been determined solely on the basis of coagulation time; currently, lumiagregometry or impedance aggregation is used. New techniques and technologies allow an ever broader view of the pathogenesis of many diseases in terms of the coagulation system’s abnormalities, which either stand for an etiologic factor or only accompany the disease (they are its result). In the course of horse colic, especially in acute and recurrent forms, there are several changes in the parameters of the hemostatic system. It is believed that DIC is the most common coagulopathy. However, there is are no definite life-extending criteria as well as postmortem diagnosis of this syndrome. Changes in blood rheology after exercise are primarily due to an increase in hematocrit. The impact of exercise on the coagulation system in horses was analyzed, and showed a tendency in EPIH horses for the occurrence of hypercoagulability with the prolongation of blood coagulation parameters. The role and the contribution of the coagulation system in the etiopathogenesis of equine laminitis is not clear; in the case of carbohydrate overdosage microtrombosis, reduced platelet survival and their over-aggregation have been reported. Clinical studies in sick animals show that coagulopathy such as DIC and antithrombin deficiency are not primary factors in the etiopathogenesis of laminitis..