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Respiratory Health and Exposures on Large Californian Dairies

California ranks first in the USA for milk production. In the San Joaquin valley and especially the two main production counties of Merced and Tulare, herd size is dramatically increasing. Indoor confinement barns are not used, but the dry, hot conditions allow for outdoor housing of cows. The large operational size of the dairies and some management practices may pose a respiratory health hazard for workers. This proposal aims to define the concentrations of airborne pollutants highly associated with respiratory problems, and study the respiratory health of the dairy workers compared to a control group of creamery employees and grain storage workers in a collaborator's study in Colorado.

This cross-sectional study will monitor personal exposure to particuate matter, endotoxins, and ammonia over a work shift in 200 dairy workers (from dairies with over 1,000 lactating cows) and 50 creamery workers. We will conduct a questionnaire to collect data on health including symptoms, personal characteristics, and allergic status. We will also conduct both pre- and post-shift measure of pulmonary function.

The hypotheses to be tested are:

California Cows!
  • Exposure to elevated concentrations of airborne pollutants will result in increased respiratory symptoms and changes in pulmonary function over the work shift; specific dairy tasks will be associated with different pollutant concentrations.

  • Long-term exposure to elevated pollutants will result in incresaed prevalence of respiratory symptoms, reduced lung function and more respiratory problems in dairies than in creamery workers.

  • Endotoxin composition will vary between dairy workers in the San Joaquin Valley and those in smaller facilities in Colorado, resulting in differences in respiratory response.

  • Diary air samples will activate macrophage cultures designed to assess inflammatory potency.

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