Effect of Particle Size of Sorghum Grains on Feed Intake and Performance of Young Broilers

Sorghum grains were ground with a hammer mill (HM) or a roller mill (RM) into three different particle sizes: fine, medium, or coarse. The ground sorghum samples were similar in their mean particle diameter and in specific surface within the three types of grinding. Six broiler starter diets (a complete factorial of two methods of preparation and three particle sizes) were fed to chicks in three experiments. In all studies, feed intake was inversely related to the calculated surface area of the ground sorghum, independent of the method of grinding. In one experiment feed intake was recorded daily during 10 days starting at 4 days of age, in a choice situation. The chicks consumed feed in accordance to its coarseness. In a short-term experiment, chicks 7 days of age were kept in individual cages (two per cage) and fed the diets following an overnight fast. Feed consumption was determined 2 and 4 h after feeding. When compared with intake of the fine diet, feed intake of the medium ground diet was 19 and 13% greater, and intake from the coarse diet was 26 and 17% greater at 2 and 4 h respectively, after feeding the two diets. Feed intake, body weight gain, and feed:gain ratio were determined in chicks kept in individual cages (two per cage) from 7 to 21 days of age. Feed intake and body weight gain were positively related to the coarseness of the feed. Feed:gain ratio did not differ among treatment groups.