Abstract: Four Holstein steers (142±9.3 kg) with cannulas in the rumen and p>roximal duodenum were used in a 4x4 Latin square experiment to evaluate the influence of corn processing on digestive function. Four dietary treatments were compared: 1) SFC (density = 0.31 kg L-1); 2) coarsely-ground corn (DRC-CG, density = 0.55 kg L-1); 3) Medium-coarsely Ground-corn (DRC-MG, density = 0.50 kg L-1) and 4) Fine-ground corn (DRC-FG, density = 0.45 kg L-1).The basal diet contained 73.25 corn and 9.8 % forage. Method of corn processing had no effect (p>0.10) on ruminal pH, VFA or methane production. There were no treatment effects (p>0.10) on ruminal digestion of feed N and ruminal microbial efficiency. Ruminal and total tract digestion of ADF was not affected (p>0.10) by corn processing. Ruminal digestibility of OM and starch was greater (12.6 and 14%, respectively; p>0.10) for SFC than for DRC-CG, DRC-MG and DRC-FG. Total-tract digestibilities of OM, starch, N and DE were greater (6.1, 3.9, 8.4 and 7.3% respectively, p>0.10) for SFC than for DRC treatments. Total tract digestibility of starch tended to increase (linear component, p>0.10) with degree of dry processing, although total tract digestibility of OM and GE was not improved (p>0.10). Given that the DE value of SFC was 4.10 Mcal kg-1, the DE values for DRC-CG, DRC-MG and DRC-FG were 3.88, 3.71 and 3.60 Mcal kg-1, respectively. It is concluded that the feeding value of dry-processed corn is not enhanced by reducing the particle size of the kernels beyond to that obtained following coarse rolling.
Alejandro Plascencia and A.V. Jose Maria , 2007. Influence of Cracked, Coarse Grind, or Fine Grind of Corn on Digestion and Rumen Function in Steers Fed a 73% Corn-Based Diet. Journal of Animal and Veterinary Advances, 6: 118-122.