Necrosis of the apex of the distal phalanx in cattle - postmortem, histological and bacteriological findings

Postmortem, histological and bacteriological findings of apical pedal bone necrosis in 18 cattle are described. Twenty-nine affected distal limbs with apical pedal bone necrosis were examined. All claws were examined for lesi ons in the sole and wall, afterwards the horn shoes were removed. The compl ete inner surface of the horn shoes and cerium was inspected to assess infl ammatory alterations. An apical pedal bone necrosis was diagnosed in 35 claws, a toe ulcer was fo und in 3 other claws. Necrosis of the apex of the distal phalanx was assess ed in 3 claws per cow in 6 cows (33.3 %), in 2 claws per cow in 5 cows (27. 8 %) and in one claw per cow in 7 cows (38.9 %). Extensive lesions of the h orn sole at the toe were visualized in 17 of 35 claws with apical pedal bon e necrosis (48.6 %), in the 21 other claws the lesions were represented onl y by small separations between the sole and the wall within the white line at the toe. The gross-pathological findings of the exungulated claws ranged from modera te topical inflammatory signs of the cerium at the toe of the claw to sever e and extensive alterations of the cerium of the complete sole and wall. In addition, slight topical or extensive bone necrosis and osteomyelitis of the pedal bone were seen. Histologically, different types of demarcation o f the necrotic bone were found, Microbiological examinations revealed predo minantly mixed infections. The visualization of the pathological changes of the complete inner surface of the cerium allowed a conclusive understanding of the severe lameness or stiff gait observed in cows with osteolysis of the apex of the pedal bone, where often only small lesions on the horn sole were visible.