COMPETENCE OF BLOOD-COAGULATION IN THE NEWBORN CALF

This study evaluated the haemostatic profiles of a group of 11 female and seven male calves from the day of birth until they mere 60 days of age. Similar results mere found for both sexes. At birth the plasma a ctivity of the procoagulant proteins, Factors VII, VIII:C, IX, X and X I and fibrinogen were all close to the adult values. Factors VII, VIII :C and fibrinogen increased transiently during the first seven days of life but the increases mere not sufficient to influence routine coagu lation screening assays such as the activated partial thromboplastin t ime and the prothrombin time. At birth, the plasma concentration of th e protease inhibitor, alpha(2)-macroglobulin, was approximately 50 per cent of adult values and increased slowly during the first seven days of life; the plasma concentration of antithrombin III was higher than that of alpha(2)-macroglobulin. The changes in the plasma concentrati on of fibronectin paralleled the changes in fibrinogen and Factor VIII :C from birth to 60 days of age; the concentrations of total plasma pr otein and plasma albumin remained stable and within the adult ranges t hroughout the 60 days. The plasma concentration of glucose increased t ransiently during the first 48 hours after birth.