Abstract: [Objective] To determine the best process parameters for preparing pelletized supplementary concentrate of cow and sheep by combinatorial use of a concentrate blender （JB-300 type） and a flat die granulator （300 type）. [Method] The impacts of varied mixing times and loading coefficients on feed blending uniformity were examined. Based on the determined process parameters of blending and mixing, the effects of different corn particle sizes and moisture contents on the molding rate of pelletized feed were assessed. To determine the best combinatorial parameters for preparing pelletized feed, the die hole diameter, corn particle size, and moisture content were used as base measurement factors, and the comprehensive weighted score of molding rate and hardness were used as evaluative index in orthogonal test. [Result] When the blending time was set to 10 min or 20 min, the variation coefficients were significantly （P<0.05） lower than when it was set to 5 min or 15 min. The variation coefficient was significantly lower （P<0.05） when the loading coefficient was 80% than when it was 70% or 60%. The molding rate of pelletized feed was significantly （P<0.05） higher when the corn particle size was 2 mm or 4 mm than when it was 6 mm or 8 mm. When the moisture content was 10% or 13%, the molding rate of pelletized feed was significantly （P<0.05） higher than when it was 16% or 19%. The extreme differences of die hole diameter, corn particle size and moisture content affecting the comprehensive weighted average score of orthogonal test were 18.76, 1.64 and 3.47, respectively. [Conclusion] The optimal parameters of the JB-300 type concentrate blender for feed mixing were loading at 80% and mixing for 10 minutes. The die hole diameter of 4 mm （compression ratio of 6）, corn particle size of 4 mm, and moisture content of 13% were the best specifications of the 300 type flat die granulator for preparing pelletized supplementary concentrate.

Key words: flat die granulator, concentrate blender, pelletized feed, process parameters