Acroosteolysis of Phalanx III in Danish Landrace pigs. A radiological and histological study.

The herd examined is considered to be a typical representative of Danish pigherds. The investigation shows that acroosteolysis is highly prevalent. As for most pathological conditions in the legs of pigs the condition is concentrated around the bigger of an uneven pair of toes. Frequency and extent of the lesions in the animals are increased with increasing age and with increasing difference in size between the paired toes. Acroosteolysis is caused by vasculitis in the distal vessels followed by osteolysis. During the later development of the condition there is no healing or callus formation in the osteolytic areas, but an extension of the free osseous areas with an apposition of osseous tissue is observed. The clinical manifestations are not specific. The condition is not hereditary, and there are no sex-correlations. The histological appearance is comparable to that of allergic reactions due to e.g. erysipeloid in pigs, and also to allergic acroosteolytic conditions in humans (Raynaud's phenomenon). Therefore, an allergic etiology cannot be rejected.