EFFECTS OF PARTICLE SIZE OF CORN, SORGHUM GRAIN, AND WHEAT ON PIG PERFORMANCE AND NUTRIENT DIGESTIBILITY

Five feeding trials and five digestion trials were conducted to evaluate the effects of particle size and surface area of corn, sorghum grain and wheat on pigs performance and nutrient digestibility. The effects of particle size on production rate and grinding efficiency were also evaluated.;Average daily gain was not influenced by particle size with any grain source or method of processing. Feed intake tended to increase as particle size increased with the lowest feed intake on the fine particle size hammermilled diet, except for sorghum grain diets for weaning pigs. Feed conversion tended to improve as the particle size decreased regardless of grain type.;Digestibilities of dry matter, nitrogen and energy improved as particle size decreased or surface area increased with corn diets for weaning and finishing pigs. However, when sorghum grain and wheat were ground with a hammermill with a 6.4 mm screen approximately 20% whole kernels resulted which reduced digestibility and tended to result in more feed being required per unit of gain. These results suggest that sorghum grain or wheat should be processed with a 3.2 mm screen or rolled to avoid whole kernels in the diet.;These studies suggest that, with energy and material costs increasing, it is becoming more important for feed manufacturers to be efficient in the processing of their products. Every feed manufacturer must be concerned with producing the most desirable feed product at the lowest possible cost. These results also suggest that, when the cost of feed processing is the same, the smaller particle size should be used. However, if the energy costs are high the feed manufacturer should consider the larger particle size resulting from coarse grinding or rolling. (Abstract shortened with permission of author.).;Average particle size diameter and geometric standard deviation increased as hammermill screen size increased regardless of grain source. Surface area decreased as particle size increased regardless of any grain source or method of processing. Production rate, grinding efficiency and true efficiency increased as particle size increased regardless of grain source or method of processing.