Comparison of Calcium Metabolism in Various Bones of Growing Chicks in Varying States of Vitamin D Supplementation

METABOLISM of calcium in the chick can be studied most usefully by estimating the ash percent, calcium content and distribution of the administered radiocalcium present in some individual bones. These procedures have been applied in the biological assay of vitamin D potency. In most such cases, the tibia has been used for analysis (Tolle, 1940; Baird and Barthen, 1941; DeWitt et al., 1942; Migicovsky and Emslie, 1950; Migicovsky and Nielsen, 1951; Keane et al., 1956; A. O. A. C, 1960; Itoh and Hatano, 1960; and Martin and Patrick, 1962a, b). The humerus and sternum have been used by Martin and Patrick (1962a), and some investigations for vitamin D assays have been developed using toe bones (Baird and MacMillan, 1942; Evans and Carver, 1944; Evans and St. John, 1944; and Campbell et al., 1945a, b) or beak (Wei et al., 1954). It seems that the tibia has been selected on the…