Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2012
Publication Date: 1/4/2013
Citation: Spiehs, M.J., Brown Brandl, T.M., Parker, D.B., Miller, D.N., Berry, E.D., Wells, J.E. 2013. Effect of bedding materials on concentration of odorous compounds and Escherichia coli in beef cattle bedded manure packs. Journal of Environmental Quality. 42(1):65-75. 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 (VFAs) and aromatic compounds (phenol, indole, skatole, 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. 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 six weeks. Corn stover, soy bean stover, wheat straw, switch grass, pine wood chips, pine wood shavings, ground corn cobs, and shredded paper were evaluated as bedding materials. Once weekly, grab samples were collected from each bedded pack and analyzed for composition of VFAs and aromatic compounds, level, growth and survival of total E. coli. Concentrations of the odorous volatile organic compounds were used to calculate an odor activity value, which is a relative measurement of the odor potential of the bedding material. The concentration of volatile organic compounds and odor activity values were highest in bedded packs containing corn cobs and shredded paper and lowest in packs containing pine wood shavings. E. coli was lower for bedded packs containing wood shavings, but all other bedding materials had similar levels of E. coli. Results of this study indicate that use of corn cobs or shredded paper may increase odor from livestock facilities, while pine wood shavings may decrease odor and E. coli in deep-bedded cattle facilities.
Technical Abstract: The objectives of this study were to determine the effect of bedding material (corn stover, soybean stover, wheat straw, switchgrass, wood chips, wood shavings, corn cobs, and shredded paper) on concentration of odorous volatile organic compounds (VOC) in bedded pack material, and to determine the effect of bedding material on the levels of total Escherichia coli in laboratory-scaled bedded manure packs. Four bedded packs of each bedding material were maintained for two six-wk periods (N = 64). Straight- and branched -chained fatty acids and aromatic compounds were measured. Corn cob bedding had the highest concentration of odorous VOC, and wood shavings had the lowest (P < 0.01). Calculated odor activity values were highest for corn cob bedding and shredded paper, and lowest for wood shavings (P < 0.01). Escherichia coli concentrations decreased from week to week for all treatments from Week 2 to Week 6. At Week 6, E. coli levels in bedded packs with shredded paper were higher (P < 0.05) than bedded packs containing wood shavings, wood chips, or switchgrass (P < 0.05). At Weeks 4, 5 and 6, E. coli concentrations in bedded packs with wood shavings were lower (P < 0.05) than bedded packs of all treatments except wood chips. Results of this study indicate that ground corn cobs or shredded paper may increase odor production and shredded paper may increase E. coli when used in deep-bedded livestock facilities, whereas wood shavings may have the least impact on air quality and E. coli.