Title: Environmental conditions in beef deep-bedded mono-slope facilities Authors
Submitted to: Iowa State University Animal Industry Report
Publication Type: Popular Publication
Publication Acceptance Date: December 6, 2010
Publication Date: December 22, 2010
Citation: Spiehs, M.J., Woodbury, B.L., Doran, B., Eigenberg, R.A., Kohl, K., Varel, V.H., Berry, E.D., Wells, J. 2010. Environmental conditions in beef deep-bedded mono-slope facilities. Iowa State University Animal Industry Report. Leaflet Number R2582. 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 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 urease inhibitors or increased frequency of cleaning in a particular area of the pen) would not effectively lower ammonia concentration in the facility. 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. Therefore, priority should be given to ammonia mitigation strategies in cattle deep-bedded confinement facilities during the hot months. 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.
Technical Abstract: The objectives of this study were as follows: 1) determine spatial variability of steady-state ammonia concentration on the pen surface in deep-bedded cattle confinement barns, 2) quantify temperature, moisture, pH, and depth of the bedding pack and relative humidity and temperature of the ambient air in the barn during various season, and determine the effect of these environmental factors on steady-state ammonia concentration, 3) determine the nutrient composition of the manure/bedding material on the pen surface, 4) determine the concentration of odorous compounds in manure/bedding material on the pen surface, and 5) determine E. coli O157:H7 occurrence and generic E. coli concentrations in manure/bedding material from beef deep-bedded monoslope facilities. Four pens (27.5 x 30.5 m) in two commercial beef deep-bedded, monoslope facilities were studied. In each pen, ammonia was collected in acid traps at 56 locations using 640 cm2 flux chambers. Moisture, pH, pack depth, nutrient composition and concentration of odorous compounds were measured at each sample location. Ammonia samples were collected at 6-week intervals for 10 months, E. coli samples for 7 months, and all other samples for 18 months. There was no consistent spatial pattern of ammonia concentration. Areas of high ammonia concentration resulted from recent urination of cattle. Ammonia concentration on the surface decreased rapidly after cattle were removed from pens, reaching an apparent baseline after 4 hours. Ammonia concentration increased as pack and ambient air temperature increased (P < 0.01) and was lower in the cold months compared to moderate and hot months (P < 0.01). Depth, moisture, and pH of bedded pack were affected by seasonal changes but were poorly correlated to the ammonia concentration of the feedlot surface of monoslope facilities (R2 = 0.07). Concentration of total volatile fatty acids (VFA), straight-chain VFA, and branch-chain VFA in manure were highest in the cold and moderate months and lowest during the hot months. The concentration of aromatic compounds in the manure was not affected by season.