The objective of this study was to measure the exposure of Irish dairy farmers to inhalable dust, endotoxin and total volatile organic compounds (TVOCs) and to explore whether levels of exposure to these agents depend on the applied feeding system in the farms.
Personal exposure measurements were collected on dairy farms using manual, loft or semi-automated feeding systems. Exposure concentrations had a geometric mean (GSD) of 1.5 mg m-3 (1.8) for inhalable dust and 128 EU m-3 (2.5) for endotoxin. Stationary measurements of VOC and CO2 concentrations inside the dairy parlours had a geometric mean of 180 ppb (1.9) and 589 ppb (1.3) respectively.
More than 50% of the exposure measurements for endotoxin, and organic dust exceeded recommended health based occupational exposure limits. Semi-automatic feeding was associated with lower levels (β=-1.04, P=0.04) of dust exposure compared to manual feeding. Handling and spreading of hay or straw was by far the strongest determinant for both inhalable dust and endotoxin exposure (β=0.55, P=0.004; β=0.72, P=0.02, respectively). The use of cow teat disinfectants was a strong predictors of TVOC concentrations within parlours.
Study results demonstrate that dairy farm workers could be exposed to high and variable levels of inhalable dust and endotoxin and may be at risk of respiratory disease.