Regulation of skeletal growth Carcasses from young animals have a relatively high bone content because the skeleton is well developed at birth. As an animal grows to market weight, its proportion of bone decreases on a relative basis, because of the growth of muscle and fat. A number of hormones exert secondary effects on skeletal development. Thyroxine, insulin, growth hormone and gonadal hormones tend to be anabolic, building up the bone mass. Estrogens may inhibit resorption of bone.
Adrenal corticosteroids stimulate resorption of bone and inhibit the formation of new bone.
In cattle, castration delays the completion of growth in epiphyseal plates. This is most noticeable in the distal bones of the limbs and enables the continued longitudinal growth of the legs. In the vertebral column, however, castration reduces bone growth. The reduction is centered on the first thoracic vertebra. Removal of the ovaries from heifers also causes an increase in the longitudinal growth of distal bones.