UC Davis     UC Davis Health System     Department of Public Health Sciences   



Study Description

  • We set out to monitor dairy air exposures and the respiratory health of 200 workers on 10 to 12 dairies located in the San Joaquin Valley in California. The dairy workers were to be compared to 50 others who have no occupational exposure to cows or dairies. The dairies all housed at least 1000 lactating cows to reflect the industry trend.

  • Each of the 250 workers (200 dairy plus 50 control) carried personal air samplers over the course of a working shift, in order to measure the concentration of dust, or specifically particulate matter in the air they were breathing. Additionally, endotoxins (cell wall fragments of gram-negative bacteria which are suspected of causing inflammation), and ammonia were monitored. Respiratory health status was assessed by comparing the pre-shift and post-shift pulmonary function tests (breathing tests using a small portable machine), and respiratory symptoms (using a questionnaire).

  • This cross-sectional design allows modeling of air pollutant concentrations and respiratory health status, and accounts for other factors such as smoking history, age, within and between-dairy location, etc. at the same time.

  • The data collected will also allow us to estimate long-term exposure to dairy dusts and its effects on respiratory health.

  • A comparison of any dose-response effects of the particles and endotoxin will be made between this study and a second NIOSH study of dairy workers in Colorado.

  • We will also investigate cellular toxicity in response to particulate matter exposure on dairies. Specifically, we will investigate the inflammation responses produced in cultured macrophages to a suspension of samples of dairy air pollutants.

  • Finally, all results of our exposure measurements and their effects on pulmonary function will be shared with dairymen and workers, with recommendations on how to reduce exposures associated with adverse effects.


The Cal-Dehri Study is a collaboration between University of California, Davis departments of Animal Science and Public Health Science, and Colorado State University and is funded by a grant from the National Institute of Occupational Safety and Health (2006-2011) Reproduction of material on this web site is hereby granted solely for personal use. No other use of this material is authorized without prior written approval ofthe UC Regents.

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