ARS | Publication request: Characterizing odors from cattle feedlots with different odor techniques

Submitted to: Air and Waste Management Annual Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 14, 2011
Publication Date: June 21, 2011
Citation: Trabue, S.L., Maghirang, R., Mcconnell, L.L. 2011. Characterizing odors from cattle feedlots with different odor techniques. Air and Waste Management Annual Conference Proceedings. Paper No. 634.

Interpretive Summary: Odors from cattle feedlots negatively affect local communities in which they operate. The purpose of this study was to characterize how odors from cattle feedlots move downwind using different odor sampling techniques. Odor determined by either human panels or chemical analysis gave similar results for samples taken onsite and downwind. At the feedlot, odors increased throughout the day and peaked in the early evening, whereas, odors measured far downwind had peaked both in the early morning and evening hours. Odors were greater in the summer than early fall. Chemical analysis showed different compounds were associated with odor depending on temperature. Research results described in this report provides needed information for growers, air quality scientist, engineers, and regulatory officials measuring odor from animal feeding operations.

Technical Abstract: Odors from cattle feedlots negatively affect local communities. The purpose of this study was to characterize odors and odorants using different odor sampling techniques. Odors were characterized with field olfactometers (Nasal Ranger®), sensory techniques (GC-O) and analytical techniques (sorbent tubes and acid traps). Odor was characterized by both dilution thresholds and odor activity values (OAV). Samples were taken off-site (upwind), on-site, and 250 m and 6.1 km downwind from large cattle feedlot. Odor intensity varied with season higher in the summer and lowest in the late fall. Odor intensity was diurnal with peak concentrations measured in late evening and early morning hours. Key odorants detected at the source included volatile fatty acids (VFA), phenol compounds, and indole compounds. Odor profile also changed with temperature with VFAs being the only key odorant late fall, but the less volatile odorants such as phenols and indole compounds being more predominate in the summer months.