Barley Rations for Swine. I. Influence of Source and Level of Dietary Protein on Rate and Efficiency of Gain of Growing Swine

Two hundred forty weanling pigs were used in two experiments to determine the influence of source of supplemental protein and level of protein upon rate and efficiency of gain of growing swine fed pelleted barley rations. In one experiment rations containing 14% protein and fed throughout the 88-day feeding period supported as rapid and efficient gains as did rations containing 16% protein until the pigs weighed 100 lb., and 13% for the remainder of the feeding period. Rations containing 12 and 13% protein supported as rapid and efficient gains in the second experiment as did those containing 14 or 15% protein initially and 11 or 12%, respectively, after the pigs weighed 100 lb. The possible effects of amino acid contents of the various rations are discussed. Replacement of a part of the soybean meal in pelleted barley-soybean meal rations with blood meal, tankage or fish meal, all high-lysine protein feeds, did not appreciably alter the lysine content of the rations within protein level. Likewise, such changes in source of supplemental protein did not significantly affect rate or efficency of gain of growing swine. Soybean meal (44%) proved to be a satisfactory source of supplemental protein in pelleted barley rations self-fed to growing swine.