HYPERTROPHIC OSTEOARTHROPATHY IN A BLESBOK (DAMALISCUS-DORCAS-PHILLIPSI)

A 4.5-yr-old female blesbok (Damaliscus dorcas phillipsi) was radiogra phed following the appearance of lameness and swelling of the right fr ont fetlock. Radiographic interpretation at that time was osteoarthrit is caused by periosteal proliferation of the right metacarpus with per iarticular osteophytes surrounding the fetlock. No treatment was initi ated. Gradual abdominal enlargement over several months was interprete d as evidence of pregnancy. Six months after the initial lameness comp laint, the blesbok suddenly collapsed and was unable to stand. Physica l examination revealed a large firm mass occupying most of the abdomen that was found to be inoperable. Following exploratory laporotomy, th e blesbok was euthanized. At necropsy, the mass weighed 17 kg. It had probably caused the animal's collapse. Histologically, the bony lesion s of the right metacarpus, seen radiographically at the previous exami nation, were consistent with hypertrophic osteoarthropathy and may hav e been a sequela of the intrabdominal mass.