Availability of the Phosphorus from Various Phosphate Materials for Swine1

Abstract

Semi-purified or natural rations were used in 6 dry lot feeding experiments to determine the availability of the P in several supplements for growing swine. The semi-purified basal ration containing beef blood fibrin as the source of protein contained 0.035% P and the supplements were added to make a total of approximately 0.30% P in the rations fed. The supplements ranked in the following order: dicalcium phosphate, monocalcium phosphate and phosphoric acid about equal followed by steamed bone meal and defluorinated phosphate, then Curacao Island phosphate and finally soft phosphate with colloidal clay the poorest. In comparisons of soft phosphate with colloidal clay with dicalcium phosphate at the same P level, the former resulted in a highly significant reduction in gains, feed intake and serum phosphorus. Also, the fluorine content of the femurs and pitting and decay of the molars increased from feeding "soft phosphate". Supplementing a practical corn-soybean oil meal ration (0.30% P) with 0.15% P from either dicalcium phosphate or phosphoric acid significantly increased gains and serum phosphorus and markedly improved feed efficiency.