Phosphorus Requirements of Laying Hens Confined to Cages

INTRODUCTION INFORMATION on the phosphorus requirements of laying hens is limited and there is a lack of unanimity in the results reported by various investigators. Norris et al. (1934) reported that the 0.75 percent level of phosphorus was adequate for normal egg production but found that a 0.5 percent level was inadequate. Miller and Bearse (1934) found that 0.80 percent phosphorus was required for optimum production when the calcium level in the ration was 2.23 or 3.00 percent. The need for additional phosphorus as the calcium level of a ration is increased was suggested by the results of Evans and Carver (1942) who observed that 0.6 percent phosphorus was adequate in laying rations containing 1.5 percent calcium but 0.8 percent phosphorus was necessary in rations containing 2.5 percent calcium. Further, when 3.0 percent calcium was included in the diet, 1.0 percent phosphorus was more satisfactory than 0.8 percent. In more …