Influence of Source of Soybean Protein, and of Pelleting, on Rate of Gain and Gain/Feed of Growing Swine

Abstract

SEVEN-HUNDRED-FORTY-FOUR crossbred pigs were used in two experiments to study the value of dry roasted and extruded soybeans as sources of supplemental protein and to investigate the value of raw soybeans in diets for finishing pigs. The effect of pelleting on the utilization of the corn-raw soybean diet was also investigated. Both dry roasted and extruded soybeans appeared to be as satisfactory as soybean meal (solvent process, 48.5% protein) as a source of supplemental protein for growing pigs. Daily gains and gain/feed were improved slightly in both experiments when the diet contained heat processed soybeans of either description. Raw soybeans were unsatisfactory as a source of supplemental protein for pigs during the growing period from about 57.5 to 95.5 kilograms. Pelleting of the diets resulted in a slight increase in daily gain compared with that obtained when the diets were fed in meal form, and gain/feed was also improved significantly. There was no indication that pelleting of the diet based on corn and raw soybeans improved the nutritional value of the protein due to heat generated during pelleting.