Dust-generating activities in stables such as mucking out and cleaning the walkways should be carried out only when the horses are not present, the authors of a scientific review urge.
Such strategies are vital to minimize the effects of dust on the health of horses, according to German researchers Gesche Claussen and Engel Hessel.
The pair, from the Georg-August University of Göttingen, conducted a review into airborne particulate matter in stables and riding arenas.
While horse owners might call it dust, scientists prefer to use the term airborne particulate matter. They categorize it based on a range of factors, including whether it is inorganic or organic in origin, and whether it comes from microbial, plant or animal sources.
The scientists, writing in the Journal of Equine Veterinary Science, traversed the range of airway diseases that can affect horses, now largely under the umbrella of “equine asthma“.
Equine airway disorders were behind significant economic losses due to performance issues, veterinary and management costs, and restrictions in use, the pair said.
They noted a rise in recent years in the incidence and severity of respiratory disorders in horses, mainly due to keeping the animals in enclosed stables and riding them in indoor arenas.
This led to continuous exposure to high concentrations of airborne particulate matter, they said, which highlighted the growing importance of preventing airway diseases in horses.
Claussen and Engel outlined a series of strategies to help minimize the impact of dust, including greater use of pasture in the keeping of horses, and more open stable and stall designs with windows for ventilation. High and airy stable buildings clearly had advantages in reducing dust concentrations, they said.
Special attention should be given to the quality of forage and concentrated feeds, as well as bedding materials.
“For forage and bedding, special care should be taken in regard to quality as well as to the production methods used,” they said.
Airborne particulate matter concentrations in both can vary widely, depending on the type and manufacturing process.
“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 were, without needing treatment, especially suitable for horses with chronic and allergic equine respiratory disorders.
Fluids, such as oil, molasses or water, can be added to concentrated feeds to minimize dust, and it is possible to treat forage by steaming or soaking.
Such measure were especially warranted to reduce dust levels in the case of poor quality fodder, concentrated feed, or bedding.
“Since most horses are kept in stables, it is of cardinal importance to ensure that activities causing high levels of airborne particulate matter such as mucking out, cleaning the stable corridors, etc, are only carried out when the horses are not present in the stables.”
The finest dust particles – a major factor in fostering airway diseases – can still be found in high concentrations in stalls hours after these activities, they warned.
Studies have shown that stable air contained considerable amounts of inorganic dust and organic particles, including bacterial endotoxins, plant debris, more than 50 species of molds, and large numbers of forage mites.
“These stable airborne particles are potential airway allergens and irritants.
“Depending on the concentration and the biological, chemical, and physical properties of the respirable airborne particulate matter, it shows different potential degrees of harmfulness for human and equine health.”
Constructive measures in regard to air flow and air exchange as well as the orientation of the stable building were important, they said.
The proper maintenance of riding-arena surfaces was also crucial in protecting horses from high dust levels.
Dust concentrations in the air around riding arenas was mainly dependent on the location, the type of footing material, the dampness of the footing, and the number of horses being trained at the same time.
For riding arenas, maintaining optimum moisture content of the footing material was important in controlling dust exposure.
“Horses suffering from ailments of the airways should only be taken into riding arenas after these have been unused for the duration of the night and only if the number of other horses is low.”
Claussen and Hessel referenced 56 scientific papers in their review.
Particulate Matter in Equestrian Stables and Riding Arenas
Gesche Claussen and Engel F. Hessel
The abstract can be read here.