Re-Evaluation of the Calcium-Phosphorus Requirements of the Chick ,

BETHKE et al. (1928) reported that the optimum calcium-phosphorus ratio for the growing chick was between 3:1 and 4:1 and within certain limits of concentration, the ratio of calcium to phosphorus was of greater importance than the amounts of these minerals in the ration. They further concluded that with a minimum dietary supply of vitamin D the ratio was more critical than when a generous amount of the vitamin was available. Hart el al. (1930) also advocated a wide calcium-phosphorus ratio (2:1 to 4:1). In the presence of abundant vitamin D and a phosphorus level of 0.3 percent, the calcium level could be varied from 0.61 to 1.13 percent wit h no ill effects. With a minimum supply of vitamin D, however, a greater degree of calcification was obtained with a calcium level of 2.49 to 2.71 percent and a phosphorus level of 0.66 t o 0.83 percent of the…