Equine asthma and respiratory disease affect a significant proportion of stabled horses, caused by exposure to dust, mold spores, and ammonia in conventional stable environments — largely preventable through environmental management.
Equine respiratory disease welfare is significantly linked to the artificial environment of the stable. Wild horses living in open environments are not exposed to the concentrated dust, mold, and ammonia of conventional stable keeping. The respiratory irritation from months or years of hay dust and ammonia exposure causes chronic inflammation, airway hypersensitivity, and eventual structural airway damage. Affected horses experience breathlessness during exercise that compounds welfare harm with physical limitation. The management solutions are effective: hay steaming, improved ventilation, wood pellet or rubber mat bedding, and turnout time all reduce respiratory particle exposure. The preventive welfare case is strong — horses managed with attention to respiratory health from the beginning of stable keeping avoid the progressive disease that results from chronic exposure.