Abstract
A 4 × 4 latin square design was employed to study the site and extent of starch digestion in steers fed processed corn grain. Steers fitted with permanent rumen and abomasal cannulae were fed a 78% corn ration (DM basis). Corn was processed by 1) dry rolling (DR), 2) steam flaking (SF), 3) high moisture harvesting-ground prior to ensiling (GHM) and 4) high moisture harvesting-whole corn treated with propionic acid prior to storage (AHM). Digestion of dry matter, organic matter and starch, ruminally and post ruminally, was determined by the lignin ratio technique. Ruminal starch digestibilities were 89.3, 82.9, 77.8 and 62.8% for GHM, SF, DR and AHM, respectively, with DR being lower (Pin vitro gas production (P<.05) upon incubation with yeast and amyloglucosidase, indicating greater disruption of starch granules. In vitro ruminal dry matter disappearance was greatest (P<.05) after 3, 6, 9 and 12 hr for GHM corn due possibly to increased protein solubilization and higher soluble nonprotein nitrogen levels in the in vitro culture. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science