Review ArticleParticulate Matter in Equestrian Stables and Riding Arenas

- Concentrate type influences the airborne particulate matter generation (APM).
- Harvesting time and conditions influences the APM generation through forage.
- Airborne particulate matter concentration of riding arenas is dependent on the footing material.
- Depending on the bedding material, different APM concentrations are set free.

Equine respiratory disorders in horses have shown a marked increase in incidence and severity during the last years. This is mainly because of the widespread practice of keeping horses in individual stalls in enclosed stables and riding them in enclosed riding arenas, leading to continuous exposure to high concentrations of airborne particulate matter (APM). Correct management and treatment of horses suffering from airway diseases are of vital importance. However, the prevention of airway diseases is also becoming increasingly important. Apart from the living environment (pasture, open stables, stalls with close-by paddocks, and stalls with exterior and interior windows), special attention has to be given to the quality of forage, concentrated feed, and bedding materials as well as maintenance of the surfaces in riding arenas to protect horses from high concentrations of APM. Since most horses are kept in stables, it is of cardinal importance to ensure that activities causing high levels of APM such as mucking out, cleaning the stable corridors, etc. are only carried out when the horses are not present in the stables. Because of the significantly lower sedimentation rate of fine particles (which are a major factor fostering the occurrence of airway diseases), they can still be found in high concentrations in the stalls hours after these activities. To reduce APM in stables, it is possible to use bedding material and forage with low contents of particulate matter such as straw pellets, wood shavings, haylage, and silage. These are (without requiring prior treatment) especially suitable for horses suffering from chronic and allergic equine respiratory disorders. Alternatively, specific treatments may be applied. Beside the use of fluid additives to concentrated feeds, it is possible to treat forage by steaming or soaking. The concentration of APM in the air of a riding arena is mainly dependent on the location (free standing or attached to the stables), the type of footing material, the humidity of the footing material, and the number of horses being trained at the same time. Because the riding arena is an important location for equestrian sports, its relevance for respiratory health of horses is very high.