396
Digestibility in steers fed modified distiller grains with solubles and corn silage to partially replace corn in finishing diets

Monday, March 16, 2015: 1:00 PM
312-313 (Community Choice Credit Union Convention Center)
Shelby E Gardine , University of Nebraska-Lincoln, Lincoln, NE
Dirk B. Burken , University of Nebraska-Lincoln, Lincoln, NE
Jana L. Harding , University of Nebraska-Lincoln, Lincoln, NE
Melissa J. Jolly-Briethaupt , University of Nebraska-Lincoln, Lincoln, NE
Terry J. Klopfenstein , University of Nebraska, Lincoln, NE
Galen E. Erickson , University of Nebraska, Lincoln, NE
J. C. MacDonald , University of Nebraska, Lincoln, NE
Brandon L Nuttelman , University of Nebraska-Lincoln, Lincoln, NE
Abstract Text:

A digestibility experiment evaluated partially replacing corn with corn silage and modified distiller grains with solubles (MDGS) in finishing diets. Six ruminally fistulated steers were used in a 5 x 6 Latin rectangle design. Treatments were organized in a 2×2+1 factorial arrangement. Factors included 15 or 45% corn silage and 20 or 40% MDGS, plus a 95% corn silage diet. Steers were assigned randomly to dietary treatment using 21-d periods with 15-d adaptation and 6-d collection. Steers were dosed twice daily with titanium dioxide 7 days before and during the collection period. Fecal grab samples were collected thrice daily, composited by day, freeze dried, and composited by steer within period. Fecal samples were analyzed for NDF, OM, and titanium concentration. Ruminal pH was recorded every minute using wireless pH probes. Rumen fluid samples were collected five times throughout day 21 of each period and were analyzed for volatile fatty acids (VFA). In situ bags containing corn bran, corn (ground to 6 mm), or corn silage, with four replicates of each ingredient, were incubated in each of the six steers for 24 or 36 h to determine impact of dietary treatment on ruminal fiber digestion. Corn bran and corn silage were evaluated for in situ NDF disappearance while corn was evaluated for DM disappearance. Total tract digestibility, ruminal VFA, and in-situ data were analyzed using the mixed procedure of SAS. Ruminal pH data were analyzed as a repeated measure using the GLIMMIX procedure. No silage x MDGS interactions were observed for DMI, total tract digestibility, ruminal pH measurements, acetate:propionate ratio (A:P), or in-situ disappearance data (P > 0.31). Greater corn silage inclusion increased DMI, NDF intake, ruminal pH, A:P, NDF disappearance of corn bran, and DM disappearance of corn (P < 0.09) and decreased DM and OM digestibility (P < 0.03). As MDGS increased in the diet, NDF intake, total VFA concentrations, and NDF disappearance of corn bran (P < 0.03) increased, with no differences in any other tested variables (P > 0.13). The 95% corn silage diet had the lowest DMI and digestibility, and total VFA concentration (P < 0.03), while ruminal pH was the greatest (P < 0.01) compared to all other treatments. These results indicate that increased inclusion of corn silage in distillers grains diets can increase ruminal pH and improve ruminal fiber digestion.

Keywords: Corn silage, Digestion, Distillers grains plus solubles