Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract only
Publication Acceptance Date: 3/3/2010
Publication Date: 5/1/2010
Citation: Varel, V.H., Wells, J., Berry, E.D., Miller, D.N. 2010. Odor Production and Escherichia coli Concentrations in Manure Slurries of Feedlot Steers Fed 0 or 40% Corn Wet Distillers Grains with Solubles. In: Proceedings of the 110th General Meeting of the American Society for Microbiology, May 23-27, 2010, San Diego, CA. 2010 CDROM. Interpretive Summary:
Technical Abstract: This study evaluated feeding 0 and 40% wet distillers grains with solubles (WDGS) diets to cattle and effects on feedlot manure collected from soil-based pens and incubated for 28 d. Steers (n = 603; 261 ± 32 kg) were fed in eight pens (15 x 150 m) of 75 to 77 steers per pen. Two experiments were conducted with WDGS; one in which the corn source fed with WDGS was high-moisture, and the second experiment in which WDGS was fed with dry-rolled corn. The objectives of this study were to compare odorants (volatile fatty acids-VFA, aromatic compounds, NH3, H2S) and persistence of Escherichia coli in feedlot manure slurries stored from 0 to 28 d. Manure collected from cattle fed 40% WDGS had lower (P < 0.05) total VFA, including acetate, propionate, and butyrate, all of which continued to be lower after 28 d. However, these slurries had greater concentrations (P < 0.05) of branched-chained VFA (isobutyrate and isovalerate), especially after d 14 of incubations. Similarly, cresol and skatole concentrations tended to be greater in slurries originating from 40% WDGS diets, and increased with incubation time. Indole was initially greater in the slurries from 40% WDGS diets; however, it was metabolized by microbes during incubation. Manure slurries from the 40% WDGS diets had greater quantities of H2S, NH3, and P (P < 0.05). Levels of E. coli in 0 and 40% WDGS manure slurries were similar when high-moisture corn was the corn source in the diets. However, when dry-rolled corn was used, E. coli persisted longer in 40% WDGS manure slurries in comparison to 0% WDGS. Results here support earlier studies that suggest feeding WDGS increases odor emissions, N loss, E. coli survival, and surface water contamination due to greater potential P run-off.