POSTMORTEM FINDINGS IN CALVES SUFFERING FROM BOVINE LEUKOCYTE ADHESION DEFICIENCY (BLAD)

Five female Holstein-Friesian calves were clinically suspected of suff ering from Bovine Leukocyte Adhesion Deficiency (BLAD), because of mul tiple recurrent infections and persistent leucocytosis. The diagnosis was established by a Polymerase Chain Reaction (PCR) technique, by whi ch a point mutation in the DNA encoding for the CD18 allele was detect ed. The animals either died spontaneously or were killed because of in curable life threatening infections. Gross post-mortem examination rev ealed severe and extensive necrotizing processes mainly located in the respiratory and digestive tract. Microscopic examination of these nec rotizing lesions demonstrated a lack of extra-vascularly located polym orphonuclear granulocytes (PMN) although vascular leucocytosis was obv ious. However, extensive catarrhal bronchopneumonia was noticed with m arked infiltration of the alveoli and bronchioli by PMN. These finding s are discussed in relation to the pathogenesis of BLAD.