Effects of Rolling on the Composition and Utilization by Growing Steers of Whole-Plant Corn Silage

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Abstract
Whole-plant corn forage chopped at .95 cm was either not further processed (control) or rolled before ensiling in trench silos. Composition and nutritive values of the resulting silages were compared in digestion and growth trials. Rolled silage had a lower proportion of kernels that were not damaged during harvest and a higher (P<.05) concentration of lactic acid than did control silage. In the digestion trial, control or rolled silages were fed as 90% of the diet dry matter (DM) in a crossover experiment to five steers (454 kg) fitted with ruminal, duodenal and ileal cannulae. Rolling of corn silage during harvest did not affect site or extent of digestion of DM, organic matter or gross energy of the diet. However, ruminal and total digestion of total alpha-glucosides were higher (P<.01), and total digestion of cell-wall constituents tended to be lower for rolled silage. Feeding rolled silage lowered (P<.05) pH and the molar proportion of propionic acid in ruminal fluid compared to feeding control silage. Feeding rolled silage did not significantly affect the ruminal retention times of either the solid or liquid digesta phases. In the growth trial, the two silages were fed as either 65% of the DM with mature alfalfa-bromegrass hay and corn grain (low energy), 90% of the DM with corn grain (medium energy) or 60% of the DM with corn grain (high energy) to 146 steers (mean weight, 237 kg) allotted to 24 pens. Steers fed the high-energy diets had greater (P<.01) DM intakes and daily gains and lower (P<.01) feed-to-gain ratios than did those fed either the low- or medium-energy diets. However, feeding rolled silage did not significantly affect any of these feedlot performance characteristics. Copyright © 1987. American Society of Animal Science . Copyright 1987 by American Society of Animal Science