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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Publications at this Location » Publication #132985
Title: THE AIRBORNE CULTURABLE MICROBIAL ECOLOGY OF SEVEN FEEDYARDS IN THE HIGH PLAINS OF TEXAS

Author
item Purdy, Charles
item Rice, William
item STRAUS, DAVID - UNIV. HSC - LUBBOCK
item WILSON, STEPHEN - UNIV. HSC - LUBBOCK
item PARKER, DAVID - TX A&M - CANYON, TX

Submitted to: American Association for Aerosol Research
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/2002
Publication Date: 10/7/2002
Citation: Purdy, C. W., Rice, W. C., Straus, D. C., Wilson, S. C., Parker, D. P. The airborne culturable microbial ecology of seven feedyards in the High Plains of Texas. Abstracts of the 21st Annual AAAR Conference. The American Association for Aerosol Research. 2002. Abstract p. 26.

Interpretive Summary:

Technical Abstract: Concentrated animal feeding operations (CAFO) produce a large amount of manure that can impact the environment if not managed properly. Environmental issues at CAFO include odor, pathogens, endotoxins (ET), and dust. The role of ET and pathogens with dust emissions was investigated. Airborne microbial concentrations of 7 CAFOs in the High Plains of Texas were determined by using 2- and 6-stage Andersen biological cascade impactors placed at 1 m height above the ground and calibrated to 28.3 L/min airflow. The impactors were positioned upwind, on-site, and downwind of each feedyard. All bacteria were collected for a 5 min interval on brain heart infusion agar (BHI) with antifungal inhibitors. Fungi were collected for 15 min on malt agar with antibiotic inhibitors. Each culture collection was replicated twice in both impactors. The colony forming units (CFU) were counted and recorded per stage, and all counts were converted to m**3 of air. Passive gravity BHI and MacConkeys plus Brilliant Green plates mounted vertically at 1 m height were replicated 6 times upwind and downwind, and exposed for 3 and 15 min respectively. ET was collected for 30 min using 2-stage impactors (glass Petri dishes containing 20 ml of pyrogen free sterile water at each stage plus 3 additional water traps). ET levels of the exposed water samples were determined by the kinetic limulus lysate assay. Microbial counts from collapsed 6-stage impactors were reported. Aerobic bacterial counts, (1441 CFU/m**3) were significantly higher than anaerobic bacterial counts (751 CFU/m**3, P = 0.004). Mesophilic bacterial counts (1441 CFU/m**3) exceeded thermophilic bacterial counts (54 CFU/m**3, P = 0.0001). Thermophilic bacterial concentrations (55 CFU/m3) were significantly higher than thermophilic fungi (2 CFU/m**3, P = 0.0001) as were mesophilic bacterial counts (1441 CFU/m**3) versus mesophilic fungi (78 CFU/m**3, P = 0.0001). No culturable gram negative enteric bacteria were recovered from the feedyard air. ET aerosol concentrations were significantly higher in winter (318 ng/m**3 ) than they were in the summer (108 ng/m**3 ).