Effect of Corn Grain Processing and Reconstitution on the Utilization of High Grain Diets for Cattle

Twelve steers (BW 433 kg ±17) were allotted to a 4 X 4 Latin square design digestion trial to examine the effects of corn processing and reconstitution on diet utilization. Diets were 84.5% corn, 7.0% ground grass hay, 4.9% soybean meal and 3.6% liquid supplement. The grain component of the diet was either dry whole corn (WC), dry rolled corn (RC), corn reconstituted with water 12 h before rolling (RRC) or corn reconstituted with water and a commercial surfactant 12 h before rolling (CRC). Reconstituted diets contained approximately 5% less DM than dry diets. Monensin and tylosin were included at 29.5 and 12.1 g/1000 kg respectively. Treatment had no effect on the digestibilities of DM (71.00% ±1.57), OM (72.22% ±1.53), CP (57.54% ±1.66), NDF (46.62% ±3.51) or starch (85.67 ±.98). To quantify differences in particle size, processed grain samples were separated with #5, 7, 10 and 18 mesh sieves. Mean percentages retained on a #5 mesh sieve were 85.26, 58.74, 84.27 and 83.57% for we, RC, RRC and CRC respectively. Subsequent fractions of WC and the reconstituted treatments were similar. In situ DMD was lower (