Effect of ingredients and processing parameters on pellet quality

Rations containing varying ratios of corn, high-oil corn, soybean meal, and mechanically expelled soybean meal were pelleted. The effects of ingredien ts, conditioning steam pressure, and mixing paddle configuration inside the conditioner on pellet quality were investigated. Ration ingredients strong ly affected pellet quality. Increasing the protein content increased the pe llet durability, whereas increasing the oil content above 7.5% greatly decr eased pellet durability. High-oil corn and mechanically expelled soybean me al produced acceptable pellets when combined with soybean meal and regular corn, respectively. However, poor pellet quality resulted when rations cont aining high-oil corn and mechanically expelled soybean meal were processed. Increasing the residence time in the conditioner by changing mixing paddle pitch resulted in an average 4.5-point increase in pellet durability indic es among 65:35 (wt) corn:soybean meal and 65:35 high-oil corn:soybean meal rations.