Clot Retraction
The formed clot plugs the ruptured area of the blood vessel and stops blood loss. In clot retraction, the fibrin clot is tightened ultimately pulling the edges of the damaged vessel closer together. The fibrin meshwork is dissolved by plasmin. In time, fibroblasts form connective tissue in the ruptured area, and new endothelial cells repair the vessel lining.
Role of Vitamin K
Normal clotting depends on adequate levels of vitamin K. Vitamin K is not directly involved in the clotting process but is required for the synthesis of 4 clotting factors. Vitamin K is a fat-soluble vitamin normally produced by bacteria of the large intestine. From there it is absorbed through the lining of the intestine and into the blood if absorption is normal in that horse. Disorders where absorption of lipids is abnormal (inadequate release of bile into the small intestine) often experience uncontrolled bleeding.
BLOOD TYPES
The surfaces of erythrocytes contain genetically determined assortment of antigens called Agglutinates. Based on the presence and absence of various antigens, blood is characterized into different Blood Groups. There are 8 different major RBC systems or groups (A, C, D, K, P, Q, T & U). These groups are independent genetic systems that control expression of factors on RBC’s Each blood group develops surface molecules or antigens called factors. More than 30 different equine RBC surface antigens have been identified. Therefore, there are approximately 400,000 possible equine blood phenotypes and a universal donor does not exist for horses.
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