Total and respirable airborne dust endotoxin concentrations in three equine management systems

Abstract

The concentrations of total and respirable airborne endotoxin in the breathing zone of a pony in 3 different management systems, on 8 occasions, are reported. Airborne endotoxin concentrations in all 3 systems were lower than those reported for many other agricultural environments. However, total airborne endotoxin concentrations in many of the conventional stables exceeded those which can induce puImonary inflammation and bronchial hyper-responsiveness in normal human subjects, and exceeded those which can induce bronchoconstriction in humans with pre-existing pulmonary inflammation. Therefore, airborne endotoxin may contribute to the development of airway inflammation and dysfunction in conventionally stabled horses. Potentially detrimental effects of airborne endotoxins on the welfare and exercise performance of stabled horses can be reduced by maintaining horses in 'low dust' stables or at pasture, since these environments had significantly lower airborne dust and endotoxin concentrations.

Elevated amount of Toll-like receptor 4 mRNA in bronchial epithelial cells is associated with airway inflammation in horses with recurrent airway obstruction

“…These observations confirm that attenuation of airway inflammation is due specifically to endotoxin. In conventional horse stables, airborne endotoxin concentrations exceed those on pasture (28) and those that can induce airway inflammation in human subjects (46,47). In our own stables, we observed that the endotoxin concentrations in the breathing zone of stabled horses are at least 10-fold higher than concentrations on pasture (unpublished data).…”

Air Quality in Horse Stables

“…Furthermore, exposure to organic dust may cause rhinitis, asthma, bronchitis, or intrinsic lung disorders such as farmer's lung/allergic alveolitis. There are several studies now showing that working in a stable can have adverse health effects on the respiratory function similar to those experienced by farmers (Kristiansen & Lahoz, 1991;Mackiewicz et al, 1996;McGorum et al, 1998;Tutluoglu et al, 2002;Elfman et al, 2009). A majority of the personnel in the race horse stable had higher levels of lysozyme and MPO in nasal lavage than white collar workers.…”

Pulmonary intravascular macrophages as proinflammatory cells in heaves, an asthma-like equine disease

“…The moldy hay environment in the present experiment contained slightly lower levels of airborne dust and airborne endotoxin compared with what has been reported for conventional stables (0.94 vs. 2.74 mg/m 3 , 18.2 vs. 19.76 ng/m 3 , respectively) but had a higher endotoxin concentration in the dust (19.4 vs. 7.57 ng/mg) (28). The alfalfa cubes environment in our study contained less endotoxin in dust than was reported for a pasture environment (2.8 vs. 4.85 ng/mg) (28), which is considered, to date, the ideal environment to achieve remission from heaves.…”