This is a simple question with a complex answer. First, you have to remember that a healthy horse rarely coughs. So if you notice a consistent cough, there is reason for concern. The most likely causes of a cough in an adult horse are viral respiratory tract infection, pharyngitis, an allergic respiratory disease (RAO or SPAOPD), pneumonia, IAD, and EIPH. With the threat of all of these illnesses, you should always consult your veterinarian if your horse develops a cough. It’s also beneficial to record when your horse coughs (e.g., during exercise, after feeding, etc.), as this can help direct the proper diagnosis.
If your horse coughs, but does not have a fever or nasal discharge, and the cough persists no matter what the level of exertion, you may be dealing with some level of an allergic respiratory disease. This is brought on by chronic exposure to allergens, most likely dust and/or mould spores. Unfortunately, just by the nature of how we stable horses, their exposure to dust and mould spores is inevitable. Reducing this exposure is essential for alleviating allergy symptoms.
The mainstay treatment for horses with RAO, SPAOPD, and IAD has always been to control the horse’s environment. This can be done by providing adequate turnout if the horse cannot continually be at pasture, using a low-dust bedding for the stall, and maintaining proper ventilation when the horse is stabled. Another effective way to control the quality of your horses’ environment is to steam their hay. While there are many advantages to steaming hay, the most important in terms of staving off allergies is that steaming kills mold spores and eliminates dust in the hay, clearing the breathing zone during feeding of the dust and allergens that can cause serious respiratory disease.
Some recommend soaking hay as a way of reducing the environmental dust. However, practically speaking, soaking hay is messy and particularly frustrating to do during the winter. Plus, many horses will not eat soaked hay very well. Alternatively, steaming hay is simple and neat, and it actually increases the palatability of the hay, resulting in less waste. Best of all, you eliminate the allergens that could be inflaming the horse’s airway and contributing to the cough.
If you find that your horse is dealing with a cough and your veterinarian diagnoses some level of allergic airway disease, ask them about steaming your hay. It is a simple solution to a common problem, and your horse will thank you for it.
RAO - Recurrent Airway Obstruction
SPAOPD - Summer Pasture Associated Obstructive Pulmonary Disease
EIPH - Exercise Induced Pulmonary Hemorrhage
IAD - Inflammatory Airway Disease