ONTOGENY OF BOVINE HEMOSTASIS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 40  (10) , 1402-1405
Abstract
Ontogeny of selected hemostatic system components was studied in 120 bovine fetuses which had been divided into 8 monthly gestational age groups. Fetal blood was tested for platelet count, partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, prothrombin and factors V and VIII. Platelet numbers corresponding to adult numbers were in fetal blood at least as early as gestation day 60, and their numbers varied only slightly thereafter. Bovine blood was incapable of in vitro coagulation at gestation day 90, with all samples coagulating by gestation day 150. Fetal coagulation screening test times (partial thromboplastin time, prothrombin time and thrombin time) shortened during gestation and were near times of adults at birth. Of the 4 individual coagulation factors tested, only factor VIII reached adult values in the fetus in utero. Amounts of fibrinogen, prothrombin and factors V and VIII in the neonate exceeded that of normal adult cattle.