Feedlot Odor Emissions Following Heavy Rainfall

Abstract

There is a need to develop predictive models for odor emissions from cattle feedlots. Surface emissions of odor from a feedlot pen were sampled under standardized aerodynamic conditions using a portable wind tunnel and tested with a forced-choice, dynamic-dilution olfactometer over a five-day period following 64 mm of rain. Pad moisture contents were monitored. No relationship between odor emission and pad moisture content alone was found even though the emission from the pad was up to 60 times greater under wet than dry conditions. A diurnal variation in emission rates was observed on some days. A hypothesis explaining the pattern of odor emission over time is proposed using an understanding of the kinetics of anaerobic fermentation. If shown correct by further research, the hypothesis will provide the basis for a model for the prediction of odor generation.