|DORAN, BETH - Iowa State University|
|KOHL, KRIS - Iowa State University|
|Wells, James - Jim|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2011
Publication Date: 3/1/2011
Citation: Spiehs, M.J., Woodbury, B.L., Doran, B.E., Eigenberg, R.A., Kohl, K.D., Varel, V.H., Berry, E.D., Wells, J. 2011. Environmental conditions in beef deep-bedded monoslope facilities: a descriptive study. Transactions of the ASABE. 54(2):663-673.
Interpretive Summary: Comprehensive manure management in livestock feeding operations needs to address nutrients, pathogens, and odors associated with the livestock waste. There is a growing interest in construction of deep-bedded confinement barns in the cattle feeding industry. Feedlot producers are using deep-bedded cattle confinement barns for a variety of reasons including ease of manure management. However, little is known about the nutrients, pathogens, or odorous compounds in the manure/bedding material that is generated in beef deep-bedded confinement barns. This study was conducted to characterize the factors impacting manure management in beef deep-bedded confinement barns as a first step towards developing recommendations for the management of these facilities to reduce odor and gas emissions and pathogens. There was no consistent spatial pattern of steady-state ammonia concentration on the pen surface of cattle deep-bedded confinement barns. Areas with a high ammonia concentration appeared to result from recent urination of cattle and occurred randomly throughout the pen. Therefore, location-specific mitigation (i.e., use of site-specific urease inhibitors or increased frequency of cleaning in a particular area of the pen) would not effectively lower ammonia concentration in the facility. Other odorous compounds were found in highest concentration on the concrete area around the bedded pack. Increased frequency of cleaning this area of the pen may reduce odor in the cattle deep-bedded facilities. Ammonia concentration was higher when the pack and ambient air temperature increased and was consistently lower in the cold months compared to moderate and hot seasons. Both E. coli O157:H7 prevalence and generic E. coli concentrations can occur at high levels in the manure/bedding material of deep-bedded cattle facilities, and may vary with differences in ambient seasonal temperatures. Therefore priority should be given to ammonia and E. coli mitigation strategies in cattle deep-bedded confinement facilities during the hot months.
Technical Abstract: There has been increased interest in feeding cattle in enclosed beef deep-bedded mono-slope facilities (BDMF). Characterization of environmental factors impacting odor and gas emissions, nutrient excretion, and pathogens is needed to develop recommendations for management of BDMF. The objectives of this study were to determine spatial variability of ammonia (NH3) concentration and odorous volatile organic compounds (VOC) in the bedded pack and quantify environmental factors during various seasons. The effects of environmental factors on concentration of NH3 and VOC were determined, as well as the nutrient content and E. coli O157:H7 occurrence and generic E. coli concentrations in bedded pack material from BDMF. Ammonia, temperature, moisture content, pH, pack depth, nutrient composition and concentration of VOC were measured at 56 locations in four pens. Areas of high NH3 concentration occurred randomly throughout pens. Ammonia concentration increased as pack and ambient air temperature increased (P < 0.01). Concentration of VOC was highest in transition areas between the bedded pack and the concrete floor. Depth, moisture content, and pH of bedded pack were poorly correlated to concentration of NH3 and VOC (r2 = 0.09). Manure from BDMF contains 80% volatile solids. E. coli O157:H7 prevalence and generic E. coli concentrations can occur at high levels in BDMF, and vary with differences in ambient temperatures. Priority should be given to NH3 and E. coli mitigation during hot months but location-specific NH3 mitigation will not be effective due to random distribution in pen. Frequent cleaning of area surrounding bedded pack should reduce VOC concentration.