HEMORRHAGIC DIATHESIS ASSOCIATED WITH A HEREDITARY PLATELET DISORDER IN SIMMENTAL CATTLE

A severe bleeding disorder in Simmental cattle has been described in w idespread locations in the USA and Canada. The clinical findings are c onsistent with a hemophilia-like disease or, more precisely, a heredit ary hemorrhagic diathesis and include spontaneous epistaxis, hematuria , and excessive bleeding associated with trauma or standard management procedures such as tattooing, ear tagging, and castration. A prelimin ary investigation of this defect showed that blood-platelet numbers an d coagulation profiles of affected cattle were normal. Affected animal s have a marked dysfunction of platelets (thrombopathy), termed Simmen tal hereditary thrombopathy. The defect is very similar or identical t o that described in the same breed by 2 other laboratories.