Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Determinants of culturable bioaerosol concentrations in dairy barns.

Authors
Lange-JL; Thorne-PS; Kullman-GJ
Source
Ann Agric Environ Med 1997 Jan; 4(2):187-194
NIOSHTIC No.
00240443
Abstract
Environmental and other factors contributing to bioaerosol exposures in dairy barns were analyzed. Three hour ambient air samples were collected from 23 dairy barns in the Midwest USA that used fodder prepared from crops grown in 1991, a season of normal rainfall, rainfall averaging 25.5 centimeters (cm) (dry barns) and from 24 barns in the region that used fodder prepared from crops grown in 1993, a season of heavy rainfall and flooding, rainfall averaging 63.0cm (wet barns). Samples were analyzed for yeasts, molds, mesophilic and thermophilic bacteria, total dust, and carbon-dioxide (124389). Dairy management practices such as type of ventilation, bulk food and bedding used and estimates of moisture content, distribution of lime for dewetting and disinfection, and animal density were determined. Time weighted geometric mean yeast, mold, mesophilic and thermophylic bacteria exposures across all barns were 1.8x10(4), 0.8x10(4), 81.1x10(4), and 0.4x10(4) colony forming units per cubic meter, respectively. Among individual barns, microorganism concentrations varied by two to three orders of magnitude, but did not vary between dry and wet barns. Barns with mixing ventilation had three to eight fold higher thermophilic concentrations than other barns. Tunnel ventilation reduced carbon- dioxide concentrations by 50%. Barns where hay was bulk feed had mold concentrations five times higher than silage use or no bulk feed. Fresh straw used as bedding, with highest moisture, produced highest mean concentrations of yeasts, molds, mesophilic bacteria, and total dust were compared to day old straw or no straw. Use of lime was highly correlated with use of fresh straw. Multiple regression analysis showed that number of cows in the barn, temperature during sampling, and use of a supply ventilation system were significant determinants of airborne yeast concentrations. Feeding dry grain and hay were associated with mold concentrations. Feeding moist grain was associated with mesophilic bacteria concentrations, and feeding silage was associated with thermophilic bacteria concentrations. The authors conclude that efforts to reduce bioaerosol exposures in dairy barns should focus on ventilation and storage moisture of feed grains.
Keywords
NIOSH-Publication; NIOSH-Cooperative-Agreement; Pulmonary-system-disorders; Organic-dusts; Aerosol-particles; Occupational-exposure; Livestock; Agricultural-industry; Pathogens; Microbiology; Ventilation-systems; Air-sampling
CODEN
AAAEFJ
CAS No.
124-38-9
Publication Date
19970101
Document Type
Journal Article
Funding Amount
1020020
Funding Type
Cooperative Agreement
Fiscal Year
1997
NTIS Accession No.
NTIS Price
Identifying No.
Cooperative-Agreement-Number-U07-CCU-706145
Issue of Publication
2
ISSN
1232-1966
Priority Area
Pulmonary-system-disorders
Source Name
Annals of Agricultural and Environmental Medicine
State
IA
Performing Organization
University of Iowa, Iowa City, Iowa
TOP