Processing and Products / Pathology / Physiology

A set of experiments was conducted to determine the effects of distillers dried grains with solubles (DDGS) on pellet quality and pelleting performance when used in corn-soy diets. All batching and mixing, processing, and subsequent testing was completed at the Department of Grain Science Feed Processing Center at Kansas State University. Observations on the viability of using DDGS were based on pellet durability index (PDI), energy usage measured in kilowatt-hours per ton (KWH/ton), production rate, and bulk density. In the pilot experiment DDGS were added to a non-nutritionally balanced diet as a replacement for corn at levels of 10%, 20%, 30%, and 40%. There were no observed significant differences in pellet quality across all levels of DDGS addition, but there were differences in production rate and bulk density. In the second experiment DDGS were added to a formulated diet at levels of 10%, 20%, 30%, and 40%, and each was compared to a control diet. In this experiment all ingredients were varied to retain nutritionally similar diets. In this case energy consumption showed no significant differences among treatments, while pellet quality, throughput, and bulk density all showed significant differences. In the final experiment DDGS were pelleted and then reground and added at levels of 10%, 20%, and 30% to a formulated diet. These diets were then pelleted and compared to a control diet with no added DDGS and to diets with unprocessed DDGS added at the same levels. At levels above 10% the diets containing unprocessed DDGS had significantly lower pellet quality than the control, while the diets containing pelleted and reground DDGS showed no significant difference from the control at any level. Significant effects were also observed for production rate, energy consumption, and bulk density. The researchers concluded that the use of standard DDGS in pelleted feeds is certainly feasible, and although pellet quality may be significantly lower for feeds containing DDGS, the practical value is likely not affected. Further, the data demonstrates some benefits of using DDGS that have been pelleted and reground.