Reduced bone mass, bone deformities, exostoses, pathologic fractures, and loose teeth (rubber jaw) are skeletal manifestations of nutritional derangements that affect parathyroid hormone function and calcium and vitamin metabolism. Specific causes such as secondary nutritional or renal hyperparathyroidism, hypovitaminosis D, and hypervitaminosis A can produce lameness. Diagnosis is by serum chemistry analyses, radiography, and identification of underlying nutritional deficiencies. Treatment is aimed at reversing the specific etiology. Surgery is rarely indicated.