Hammermill screen selection for soybean processing: soybean meal particle size and pullet performance effects

Reducing the particle size (PS) of feed ingredients is necessary and requires substantial energy expenditure. A majority of research on ingredient PS has considered the effects of corn and wheat PS on poultry performance. However, there is limited research investigating the effects of soybean meal (SBM) PS. Two experiments were conducted using expeller extruded SBM to measure the energy required to reduce soybean meal cake PS at the processor (experiment 1) and to determine the effects of various SBM PS on pullet performance from 0 to 17 weeks of age (experiment 2). The PS of SBM used in the current study was reduced using a hammermill fitted with one of three screens (2.4 mm, 5.6 mm, 7.9 mm) which represent the three treatments used in experiments 1 and 2. In experiment 1, hammermill screen size influenced motor load and power usage of the hammermill motor. The 2.4 mm screen required more energy and power to reduce the PS of SBM cake compared to all other screen sizes (P < 0.001). Experiment 2 used three identical diets that varied only in SBM PS. Overall, mash diets varying in SBM PS did not influence the measured pullet performance parameters which included FI, BWG, and FCR (P > 0.05). These data indicate that SBM may be manufactured using larger screen sizes to reduce energy usage at soybean processing facilities with no impact on ready-to-lay pullet development.