THE CALCIUM, PHOSPHORUS, AND ZINC BALANCE IN PIGS AS INFLUENCED BY THE WEIGHT OF PIG AND THE LEVEL OF CALCIUM, ZINC, AND VITAMIN D IN THE RATION

Abstract

Digestion and metabolism experiments were carried out with pigs of various body weights (20, 35, 55, and 80 lb.) using 4 × 4 latin square designs of experiment to determine the effects of supplementing a ration with calcium, zinc, and vitamin D on the apparent absorption and retention of calcium, phosphorus, and zinc. The levels of calcium, zinc, and vitamin D in the rations were 0.40 and 0.86 per cent, 34 and 140 p.p.m., and 0 and 800 i.u. per lb. respectively. The pigs were hand-fed the rations in slop form.Body weight gains and appetite were not affected by the addition of calcium, zinc, or vitamin D to the rations. Symptoms of parakeratosis appeared when the pigs were fed the basal or the basal-plus-calcium rations, but not when the rations containing supplemental zinc were fed.The apparent absorption and retention of calcium were not influenced (P = 0.05) by the addition of calcium or vitamin D to the ration or by the weight of pig, but were increased (P < 0.10) by the addition of zinc to the ration. The apparent absorption of phosphorus was decreased (P < 0.01) by the addition of calcium or vitamin D to the rations but was not influenced by the addition of zinc or by weight of pig. The retention of the phosphorus consumed was not affected by calcium, zinc, vitamin D, or weight of pig. The apparent absorption and retention of zinc were increased (P < 0.01) by the addition of zinc, decreased (P < 0.01) by the addition of vitamin D, and unaffected by the addition of calcium to the ration. The apparent absorption of zinc by the 20-lb. pigs was greater (P < 0.01) than by the pigs of other weights and less (P < 0.05) by the 35-lb. pigs than by the pigs of other weights. Most of the zinc consumed was excreted in the feces.The results of this experiment indicate that a high vitamin D content of the ration and weight of pig may be of importance in the development of parakeratosis.