Purdue University Agricultural Experiment Station Lafayette, Indiana
Mimeo A. H. 215 November 20, 1957 (Final Report
PHOSPHORUS AND PROTEIN LEVELS FOR GROWING-FINISHING SWINE
ON LEGUME PASTURE
C. E. Jordan, J. H. Conrad, M. P. Plumlee, and W. M. Beeson Department of Animal Husbandry
The animal body normally contains approximately 1.5$ calcium and 1,0$ phosphorus, About 98$ of the calcium and 85$ of the phosphorus is in the skeleton.
Aside from its commonly recognized function as part of the skeleton, phosphorus has essential and irreplaceable functions in every cell of the body. Phosphorus is required for the metabolism of proteins, lipids, (fat) and carbohydrates. It is a constituent of many enzymes and is either a constituent of or aids directly in the proper functioning of many vitamins. Contrary to many common beliefs, the fast growing or high producing animal does not maintain much of a ”surplus” of phosphorus or calcium within its body at any given time regardless of the diet. Dietary excesses are usually not absorbed from the digestive tract, or if they are they will usually be excreted principally via the urine. In view of this, swine rations should be adequate in phosphorus and calcium at all times.
The accepted phosphorus requirements of swine expressed as percent of the total ration are: 25 lb. pig, 0,6C$; 50 to 150 lb. pig, 0,45$; 150 to 250 lb. pig, 0.33$; and all breeding stock, 0.4C$. Table 1 shows the protein, phosphorus and calcium content of some commonly used swine feeds. It is seen that the grains are deficient in all three nutrients (assuming poor availability of the phytin phosphorus) for swine. Also, that protein supplement feeds contain more phosphorus and calcium than the grains with the animal by-products containing many times more of each than the plant protein sources. Swine rations high in corn and soybean oil meal and low in animal by-products feeds will usually contain from 0.25 to 0.35$ phosphorus, including the ’’unavailable” phytin phosphorus. Thus, for best animal performance such rations should be supplemented with phosphorus. When the feeder raises the protein content of swine rations he is also raising the phosphorus and calcium content. If improved growth or feed efficiency results, it is usually explained on the basis of the increased protein. The increased phosphorus and calcium intake may have been and probably were partially responsible.
This experiment was designed to compare corn-soy rations containing different protein and phosphorus levels when self fed to growing-finishing swine on good ladino clover pasture.
Seventy-two Duroc weanling pigs averaging 34 pounds were allotted to six lots on the basis of age, sex, liveweight and general appearance. All pigs were fed complete mixed rations on ladino clover pasture. The experiment started May 24,1957.
Tables 2A and 2B show the composition of the rations and the treatments for the respective lots. Briefly, the treatments were:
Purpose
Experimental Plan
Acknowledgement is made to Fred Vandergraff, Swine Herdsman, and his associates for feeding and caring for the experimental animals.