The Effect of Low Phosphorus Rations on Egg Production and Hatchability

THE phosphorus requirements of laying pullets have not been extensively studied. Branion (1938) concluded that mineral supplements should be fed ad libitum due to the disparity in the calcium and phosphorus requirements as found by various investigators. Miller and Bearse (1934) stated that approximately 0.80 percent phosphorus was required for optimum production when the fixed calcium content of the ration was 2.23 or 3.00 percent. Norris et al. (1934) found that 0.5 percent phosphorus was not sufficient for egg production but 0.75 percent was adequate. In 1937 Mitchell and McClure expressed the requirement by standardizing the production at 75 percent and phosphorus availability at 50 percent. Under those conditions the requirement was calculated to be 0.35 percent phosphorus. Schaible (1941) reviewed the literature and concluded that 0.4 percent phosphorus was required but to allow for a margin of safety 0.5 percent was recommended. Evans and Carver (1942) stated the phosphorus …