Nutritional secondary hyperparathyroidism in a lion cub

A female lion cub about 5 months old from a litter raised artificially in a lion park, was euthanased and necropsied. The history was one of poor growth, lameness, a reluctance to move and skeletal malformations with disproportionately large head and feet. The cub had been fed meat and milk supplemented with calcium and vitamins. All the bones in the body were exceptionally soft and flexible. The long bones, vertebrae and ribs were easily split in half with a knife. The scapulae were deformed and medially curved. The long bones were shorter and thicker in diameter than normal, with very thin cortices. Numerous pathological fractures exhibiting minimal callus formation were present. The ribs were rounded, abnormally curved and very short in comparison to the length of costal cartilages. Radiographically, a marked osteoporosis was observed. Histopathological examination revealed a severe diffuse fibrous osteodystrophy with very little bone present. The osteoid was improperly mineralised and tissue sections for microscopy were cut without any need for prior decalcification. Little space for haemopoietic tissue remained. The lesions were considered consistent with those in animals raised on a diet containing excessive phosphates and low calcium.