A bleeding disease (von Willebrand's disease) in a Chesapeake Bay Retriever

A bleeding disease similar to von Willebrand's disease in man was diagnosed in a 6-month-old Chesapeake Bay Retriever with recurrent, protracted gingival hemorrhage that responded rapidly to fresh, whole blood transfusions. The dog had a prolonged bleeding time and low plasma factor VIII coagulant activity (18%). The plasma had no detectable factor VIII-related antigen or von Willebrand factor, as measured by ristocetin-cofactor and polybrene-cofactor activities. The dam of the dog had a plasma factor VIII-related antigen concentration (32%) well below the normal range. The antigen in the sire's plasma was at the low end of the normal range, as was the polybrene-cofactor of both the sire and the dam. These data suggested an inherited basis for von Willebrand's disease in this dog.