Submitted to: Extension Fact Sheets
Publication Type: Other
Publication Acceptance Date: 11/15/2013
Publication Date: 11/18/2013
Citation: Doran, B., Kohl, K., Rieck-Hinz, A., Cortus, E., Spiehs, M.J. 2013. Air quality in bedded mono-slope beef barns. Iowa State University Extension Fact Sheet. PM 3062, November, 2013. Interpretive Summary:
Technical Abstract: Bedded mono-slope barns are becoming more common in the upper Midwest. Because these are new facilities, little research has been published regarding environmental quality, building management and animal performance in these facilities. A team of researchers from South Dakota State University, USDA ARS U.S. Meat Animal Research Center, Iowa State University, and University of Nebraska – Lincoln investigated air quality in these barns. The objectives of the study were 1) to gather baseline data for the levels of gas emissions and particulate matter (PM) from bedded mono-slope beef barns, 2) to evaluate the effect of two different manure handling systems (Pack and Scrape) on air quality, and 3) to provide information about building and management practices that may reduce gas emissions. The study measured gases and PM from four mono-slope beef finishing barns – two used a Scrape systems in which all bedding material and manure was removed weekly, and two used a Pack system in which bedding and manure was allowed to remain in the pen until the cattle were marketed with only the bunk aprons and the area around the pack scraped weekly for manure removal. Ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4) were measured for month-long periods in each barn during each season over a two-year time span. Environmental conditions (temperature, relative humidity, and air speed) were also monitored. Particulate matter was measured over two five-day periods in one Pack barn to compare PM concentration during hours of routine operation and PM concentration during a bedding event. In the Scrape barns, 24-hour collections of PM occurred at least twice during each monitoring period. Average gas concentrations ranged from 23 – 103 ppb for H2S, 2100 – 3800 ppb for NH3, and 6200 to 9200 ppb for CH4. As airflow through the barn decreased, gas concentrations in the barn increased. Concentration of H2S increased with increasing temperature for both Pack and Scrape barns, but the increase was greater and more variable for Pack barns. In the Pack barn, overall concentration of total suspended particulates (TSP) were 59 and 702 µg/m3 for hours of routine operation and a bedding event, respectively. The PM concentration in Scrape and Pack barns during routine operation are lower that reported values for open feedlots. The PM concentrations in Pack barns during a bedding event are slightly higher than open feedlots, but these bedding events are short-lived and PM concentrations quickly return to baseline levels. Building orientation, pen density, type of bedding material, ventilation and curtain openings, and manure handling systems may all influence air quality in beef mono-slope facility and should be considered to improve air quality and animal comfort.