Date of this Version
The calcium and phosphorus requirements of growing-finishing swine have not been satisfactorily resolved. Recently it was suggested that levels of calcium and phosphorus needed in diets of growing-finishing (G-F) swine for optimum growth and feed conversion may be different from those needed for optimum bone development (Miller et al., 1960; Lloyd et al., 1961; Rutledge et al., 1961; Combs et al., 1966). The problem of determining calcium and phosphorus requirements is further magnified by the observation of Chapman et al. (1955) that G-F swine do not utilize plant phosphorus as efficiently as inorganic phosphorus. In addition, Chapman et al. (1962) reported that phosphorus had a greater effect on growth, feed conversion and bone development than calcium and that the calcium-phosphorus ratio is more important than dietary levels of phosphorus for optimum over-all performance.