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Airborne microbial flora in a cattle feedlot
S C Wilson1, J Morrow-Tesch, D C Straus
1Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA. stewilso@ttacs.ttu.edu
Applied and Environmental Microbiology
|June 29, 2002
Summary
Two feeding patterns were studied in cattle feedlots to assess airborne microorganisms and dust. While one pattern reduced dust, neither feeding strategy significantly altered microbial numbers or diversity in the air.
Area of Science:
- Environmental microbiology
- Animal science
- Agricultural engineering
Background:
- Cattle feedlots generate airborne dust and microorganisms, impacting air quality and animal health.
- Understanding microbial populations in feedlot air is crucial for environmental and occupational health assessments.
Purpose of the Study:
- To quantify and identify microorganisms in cattle feedlot air.
- To evaluate the impact of two feeding patterns on airborne dust generation and microbial load.
Main Methods:
- Utilized Dustrak monitors to measure fine dust particles (≤2.5 µm).
- Employed Andersen biological cascade samplers for bacteria and fungi capture and identification.
- Collected microbial and dust samples over 4 days at upwind and downwind sites.
Main Results:
- Only nonpathogenic gram-positive bacteria were cultured; gram-negative bacteria may exist in a viable but nonculturable state.
- Fungal populations were lower than bacterial populations, and all isolated fungi were nonpathogenic.
- One feeding pattern significantly reduced downwind dust levels (P=0.04), but no feeding pattern affected total microbial numbers or diversity.
Conclusions:
- Feeding patterns can influence dust generation in feedlots, but not necessarily the overall microbial air content.
- Discrepancies between dust and microbial sampling suggest different system operating principles.
- Microbial loads in this study were lower than those reported for other intensively housed livestock.