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Airborne particulates ( PM 10) and tracheal mucus: A case–control study at an A merican Thoroughbred racetrack
Author(s) -
MillerickMay M. L.,
Karmaus W.,
Derksen F. J.,
Berthold B.,
Robinson N. E.
Publication year - 2015
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12303
Subject(s) - mucus , food science , chemistry , microbiology and biotechnology , biology , ecology
Summary Reasons for performing study Particle mapping within stalls has demonstrated a relationship between particulate concentrations and visible accumulations of tracheal mucus. However, measurement of breathing zone particulate concentrations, which is the most accurate way to measure exposure, has not been performed to determine the relationship between exposures and accumulations of tracheal mucus sufficient to affect performance. Objectives To compare breathing zone particulate exposures between horses with tracheal mucus scores ( MS ) previously demonstrated to affect performance ( MS ≥2) and those without ( MS = 0) visible tracheal mucus. Study design Case–control study. Methods We endoscopically examined 649 Thoroughbred racehorses over 7 months and selected 113 age‐matched cases and controls based on the presence ( MS ≥2) or absence ( MS = 0) of tracheal mucus, respectively. Inflammatory cell numbers in tracheal lavage were also determined. Breathing zone monitors recorded particulate exposure during 3 time periods (mid‐day, evening and overnight). Total recording time averaged 17.5 h/horse. Results The overall prevalence of MS ≥2 in the observed stables was 23%. Breathing zone particular matter ( PM 10) concentrations were very similar to previously reported ambient concentrations. During the evening and overnight, cases had significantly higher breathing zone PM 10 concentrations and neutrophil counts than controls. Inflammatory cell counts were associated with average PM 10 concentrations throughout the day. Conclusions Breathing zone particulate concentrations are associated with MS ≥2 and inflammatory cell numbers. If breathing zone particulate exposures are predominantly influenced by ambient PM concentrations, racing stable management practices to reduce particle exposures should greatly reduce the prevalence of tracheal mucus.