Identification of factor XI deficiency in Holstein-Friesian cattle in Britain.

Blood coagulation tests were performed on dairy cattle in a herd with haemorrhagic problems on a farm in Gloucestershire. The characteristic pattern of prolonged partial thromboplastin time with normal prothrombin time and thrombin time was shown to be associated with a partial factor XI deficiency, a congenital defect previously identified in cattle in North America.