Equine Asthma

 Horses can develop equine asthma when theyre exposed to airborne organic dust that can be found anywhere in a dirt paddock on a gravel road or in an indoor arena. But the most common culprit is dusty moldy hay. Round bales can be particularly problematic as horses tend to tunnel their muzzles into the bales and inhale dust and mold.
The disease affects horses of any breed typically when they are middleaged and older.
Experts now suggest that veterinarians use the term equine asthma instead of RAO to describe this disease. RAO will be considered severe equine asthma. Less chronic airway inflammation such as inflammatory airway disease that is commonly found in young race horses will be termed mild to moderate equine asthma. 

1 What are the clinical signs of equine asthma?
Affected horses usually have a chronic cough that may occur randomly or while eating or exercising. In addition theyre often intolerant of exercise have nasal discharge and have more laboured breathing. More severely affected horses may have a heave line a ridge of muscle along the abdomen that develops because of the overuse of respiratory muscles.
2 How is equine asthma diagnosed?
The veterinarian listens to the horses lungs using a stethoscope and a rebreathing bag a plastic bag placed over the horses muzzle. Some abnormal sounds that may be present in the lungs of a horse with equine asthma include harsher louder lung sounds wheezes crackles and a tracheal rattle. To accentuate these abnormal sounds your veterinarian may place a rebreathing bag over the horses muzzle and allow it to breathe into the bag for a minute or two. Rebreathing the expired air encourages the horse to breathe deeper.
In some cases the history of the horses problem and physical exam can be enough for the veterinarian to start treating the horse for equine asthma. However to make a definitive diagnosis its necessary to perform a bronchoalveolar lavage BAL. The BAL procedure which is very safe for the horse allows the veterinarian to determine the severity of the inflammation in the lungs. It also provides baseline information that can help clinicians determine if your horse is improving with treatment. It may also be necessary to perform a tracheal wash to rule out pneumonia an infection in the lungs.
3 How important is an early diagnosis?
If the disease is identified before any permanent damage is done to the lungs your horse can continue to breathe