Title: Use of wood-based materials in beef bedded manure packs Part 2: Effect on odorous volatile organic compounds, odor activity value, Escherichia coli, and nutrient concentrations Authors
|Brown Brandl, Tami|
|Parker, David -|
|Jaderborg, Jeffrey -|
|Dicostanzo, Alfredo -|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2013
Publication Date: N/A
Interpretive Summary: Livestock producers are faced with increasing pressure to reduce or eliminate odors and pathogens from their facilities. Volatile organic compounds such as volatile fatty acids and aromatic compounds (phenol, indole, skatole, and p-cresol) are targeted for reduction due to their unpleasant odors and low odor threshold. Enteric bacteria in the manure/bedding from confined livestock facilities can provide a source of pathogens for contamination of additional cattle in the barn, of ground or surface waters by runoff from the manure storage area, or of soil or food/feed crops when the manure/bedding mixture is applied to cropland. Bedding material may be one management tool that can reduce odors or pathogens in livestock facilities. Many different types of bedding material are used by livestock producers. Differences in chemical and physical characteristics of the bedding materials will influence how well the bedding absorbs urine and feces, how quickly the bedding is decomposed, and ultimately, how the bedding material will affect odors and pathogens in livestock facilities. Previous studies have shown that bedded packs containing wood-based bedding materials had lower concentrations of odorous compounds and E. coli compared to corn stover. The objectives of this study were to determine the effect of bedding material on concentration of odorous volatile organic compounds in bedded pack material, and to determine the effects of different bedding materials on the levels, growth, or survival of total E. coli in simulated manure bedded packs. Lab-scaled bedded manure packs were established and housed in environmentally controlled rooms for 42 days. Corn stover and three types of wood-based bedding materials (kiln-dried pine chips, dry cedar chips, and green cedar chips) were evaluated as bedding materials. Once weekly, grab samples were collected from each bedded pack and analyzed for level, growth and survival of total E. coli. Concentrations of the odorous volatile organic compounds were collected at days 0, 21, and 42 and were used to calculate an odor activity value, which is a relative measurement of the odor potential of the bedding material. As the bedded packs aged, the concentration of odorous volatile organic compounds increased, particularly in the bedded packs containing green cedar chips and dry cedar chips. Over the 42-day period, concentration of volatile organic compounds and odor activity values were highest in bedded packs containing green cedar chips and lowest in bedded packs containing pine chips. Total E. Coli concentrations increased from day 0 to 21, and then began to decline, and were similar among all bedding materials. Results of this study indicate that producers using a long-term bedded pack management in their facility may benefit from using pine chips as they do not appear to increase odor over time. Cedar-based bedding materials and corn stover may be better suited management systems where the bedded pack is removed after one or two weeks. Total E. coli concentrations did not differ between any of the four bedding materials over time.
Technical Abstract: The objectives of this study were to determine the effects of three types of wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, and green cedar chips) and corn stover on concentration of odorous volatile organic compounds (VOC) and total Escherichia coli in bedded pack material. Four bedded packs of each bedding material were maintained for two 42-day periods (N = 32; 8 replicates/bedding material). Straight- and branched-chained fatty acids, aromatic compounds, and sulfide compounds were measured from the headspace above each bedded pack. Green cedar bedding had the highest concentration of odorous VOC and pine chip bedding had the lowest (P < 0.01). Calculated odor activity values were highest for green cedar bedding, followed by dry cedar, corn stover, and pine chip bedding. As the bedded packs aged, the concentration of odorous VOC increased, particularly in the bedded packs containing green cedar chips and dry cedar chips. Total E.coli concentrations increased from Day 0 to 21, then began to decline, and were similar among all bedding materials (P < 0.10). Results of this study indicate that producers using a long-term bedded pack management in their facility may benefit from using pine chips as they do not appear to increase odor over time. Cedar-based bedding materials and corn stover may be better suited for a scrape-and-haul system, where the bedded pack is removed after one or two weeks. Total E. coli concentrations did not differ between any of the four bedding materials over time.