The overall objective of this research is to help producers decide whether they should invest in a 2-High, 3-High, or 4-High roller mill when considering technology to reduce particle size to maximize performance of nursery pigs, finishing pigs, as well as feedmill efficiency. In order to accomplish the overall objective, three experiments were conducted to evaluate the effects of various roller mill configurations on feed preference of nursery pigs, growth performance of nursery and finishing pigs, carcass characteristics of finishing pigs, and feedmill throughput and economic implications. In Exp. 1, diets were fed with the corn fraction ground using two, three, or four sets of grinding rolls in various configurations to determine growth performance of nursery pigs. In Exp. 2, diets were fed with the corn fraction ground using the same roller mill configurations to Exp. 1 to determine feed preference in nursery pigs. In Exp. 3, diets were fed to finishing pigs with the corn fraction ground using identical roller mill configurations to determine growth performance, carcass characteristics, and throughput and electricity consumption of the roller mill.
In nursery pigs, there were no observed differences in gain, feed consumption, feed efficiency, or economics for the roller mill configurations. However, there was a clear impact of roller mill configuration on feed preference, due to the particle size of the respective diets. In finishing pigs, ADFI and ADG were reduced when the particle size was reduced from 685 µ to 360 µ, with no observed improvement in feed efficiency. Although roller mill configuration had a substantial impact on the electricity cost and throughput, results did not indicate any benefit in feed efficiency or economic return when particle size was reduced below 685 µ by grinding through a roller mill when fed to finishing pigs.

Producer bottom line;
• Earlier research has shown a decrease in gain and feed intake when corn particle size is reduced below approximately 600 µ and fed in meal diets; however, the appreciable benefit in feed efficiency normally found with particle size reduction was not observed in these studies.
• Lowering particle size by increasing the number of grinding rolls increased electricity cost and decreased throughput.
• No benefit in performance or economics was observed when corn particle size was reduced below 650 µ and fed in meal diets to nursery or finishing pigs.
• Field experience indicates that a 3-high roller mill allows producers to more easily reach their particle size targets; however, these trials indicate no advantage to use of a 4-high roller mill.

Dr. Mike Tokach                                                    Jordan Gebhardt
Kansas State University                                        Kansas State University
Department of Animal Sciences & Industry          Department of Animal Sciences & Industry
222 Weber Hall                                                      217 Weber Hall
Manhattan, KS 66506                                           Manhattan, KS 66506
785-532-2032""                                                    785-532-1270""
[email protected]                                                 [email protected]