As the number of grinding treatments increased,the mass median particle diameters of fine-ground millfeeds declined. For HRS, the median particle diameters were 307, 260,225, and 178 mm, respectively, from the 1st grinding to the 4th grinding treatment; while for HRW, they were 319, 274, 235, and 185 mm, respectively, from the 1st grinding to the 4th grinding
treatment.