Extrusion results in increased digestibility of energy, which is primarily due to increased gelatinization of starch. Because this process improves flavor of cereal grains, it is known that extrusion improves palatability in pig diets. Particle size reduction in cereal grains results in an improved digestibility of nutrients due to increased surface area of grains, which subsequently increases the interaction with digestive enzymes. However, because grinding changes the textural traits of grains, the palatability of feeds is low and thus feed intake of pigs is often reduced.

The feed preference of pigs may be influenced by the characteristics of feed ingredients included in diets, but it is not known if different particle size of extruded corn affects the feed preference of weanling pigs. Therefore, the objective was to test the null hypothesis that there were no effects of reducing particle size of extruded corn on feed preference by weanling pigs.