Funk, Sara, authorReynolds, Stephen J., advisorRoman-Muniz, Noa, committee memberVolckens, John, committee member2007-01-032007-01-032011http://hdl.handle.net/10217/47272This pilot study measured the impact of seasonal ventilation changes on concentrations of organic dust, endotoxin and bacteria in one modern dairy milking parlor. Pyrosequencing, a new non-target specific molecular methodology was used to characterize airborne bioaerosols. Area samples for inhalable dust, respirable dust, endotoxin, and bacteria were collected in one modern dairy parlor during both summer and winter seasons. Five sampling sessions were performed at approximately weekly intervals during each season. The summer season included an open facility with fresh mechanical air ventilation. The winter season consisted of a closed facility with no fresh air ventilation and forced heat. Aerosol size distributions, air velocity inside the parlor, humidity, temperature, and CO2 were also sampled on each trip. Two-way ANOVA was performed to test statistically significant differences between variables. No significant differences between mean concentrations of inhalable dust, respirable dust, or bacteria were seen by season. Endotoxin showed a near significant difference (p=0.06). CO2 concentration doubled during the winter season as compared to the summer (p<0.001) due to reduced ventilation. The aerosol size distribution did not vary between seasons (MMOD=12µm) indicating that seasonal ventilation changes do not affect the particle size distribution. The most common bacterial genera in both seasons were Clostridium (anaerobic), Oscillibacter and Staphylococcus - all Gram positive bacteria. Gram-positive bacterial genera occurred more frequently during the summer than winter seasons. Gram-negative bacteria cell counts increased in the winter season. Average concentrations of total bacteria in the facility during summer and winter were 2839 and 7008 counts/m3, respectively. This study was the first to apply Pyrosequencing to measure bioaerosols in a dairy environment. The diversity of bacteria and predominance of Gram-positive bacteria is consistent with studies in swine and poultry facilities. Concentrations of dust, endotoxin, and bacteria were low during both seasons in this milking parlor, most likely due to the new construction of the facility. These study results will inform the design of future comprehensive studies of aerosol exposure interventions in dairy operations. Understanding these aerosol exposures and potential interventions is important for reducing respiratory disease among workers in the dairy industry.born digitalmasters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.bacteriapyrosequencingendotoxindustdairyText