#11-170

Complete

Date Full Report Received

04/01/2013

Date Abstract Report Received

04/01/2013

Investigation

Institution:
Primary Investigator:

The objective of this research was to measure the effects of different particle sizes of corn on energy and nutrient digestibility and to test the hypothesis that diets containing corn with reduced particle size can be formulated with less fat than diets containing corn ground to a greater particle size. Two digestibility experiments were conducted to determine effects of corn particle size on digestibility of energy, amino acids, and phosphorus in corn. Results of these experiments indicated that whereas the digestibility of amino acids and phosphorus is not influenced by the particle size of corn, the digestibility of energy is linearly increased if the particle size of corn is reduced from 865 to 339 microns. As a consequence of the greater digestibility of energy in corn ground to the smaller particle size, the concentration of metabolizable energy in corn ground to 339 microns is approximately 3.6% greater than if corn is ground to 865 microns (3,964 vs. 3,868 kcal ME per kg DM). Because of this increase in ME, it is possible to reduce the amount of added fat in diets containing corn ground to a smaller particle size compared with diets containing corn ground to a greater particle size withoutchanging the ME of the diet. Therefore, in the third experiment, diets that contained corn ground to 865, 677, 485, or 339 microns were formulated and fed to pigs from approximately 32 to 130 kg in a 3-phase feeding strategy. Within each phase, all diets were formulated to contain equal quantities of ME per kg, but diets formulated with the corn ground to 865 microns contained 1.60, 1.74, and 1.87% more soybean oil than diets containing corn ground to 339 microns for phase 1, phase 2, and phase 3, respectively. Results of this experiment indicated that final body weight, ADG, ADFI, G:F ratio, hot carcass weight, and dressing percentage were not different among pigs fed experimental diets. This observation confirms that the ME of corn ground to smaller particle size is indeed greater than if corn is ground to a greater particle size. The practical consequence of this is that less fat is needed in diets containing corn ground to a smaller particle size compared with diets containing corn ground to a greater particle size. Diets containing corn ground to the smaller particle size are, therefore, less expensive to produce than diets containing corn ground to a greater particle size, and the savings in feed cost will not have any impacts on pig growth performance or carcass composition. The net result, therefore, will be an increase in profits from pigs fed diets containing corn ground to a smaller particle size. Pork producers can take advantage of the results from this research by grinding corn to a reduced particle size.
For more information, please contact Dr. Hans H. Stein (email: hstein@illinois.edu)