BLEEDING DIATHESIS ASSOCIATED WITH VARIANT VON-WILLEBRAND-FACTOR IN ASIMMENTAL CALF

Platelet count, platelet volume, and coagulation function were all wit hin normal ranges in a calf determined to have a bleeding diathesis as sociated with variant von Willebrand factor (vWF). Mucosal bleeding ti me was high, and platelet adhesion to glass beads and platelet aggrega tion in response to adenosine diphosphate were low. The concentration of VWF was within normal limits, but the functional vWF activity was l ow and the structure was truncated.