Is it normal for a horse to cough?
The short answer is no! It is not normal for a horse to cough at rest, or at the beginning of a riding session. If your horse does cough occasionally or regularly, it suggests some degree of lung disease, and further steps need to be taken to ensure it doesn’t escalate further.
Is it normal for a horse to have a runny nose?
A small amount (few drops) of a clear, watery nasal discharge is normal. Increased volumes of watery discharge of any colour (white, yellow, green, red) are abnormal.
What do I need to do about it?
In the first instance, it is worth asking a vet to examine your horse. Equine asthma (previously RAO, COPD) is very common, but there are other causes of coughing and runny noses that must be ruled out first. In every case, acting sooner rather than later is highly likely to improve the chances of a positive response to treatment.
What is equine asthma?
Equine asthma is the most common respiratory disease in older horses (7+yrs). Equine asthma is classified as either mild, moderate or severe based on the clinical signs seen at rest. These can range from none, and the only sign seen is exercise intolerance, through to obviously laboured breathing.
Severe equine asthma is believed to be caused by an allergy to airborne particles (allergens) in the environment. Typically, clinical signs are linked to the stable environment, which is why signs of equine asthma are more common in the winter. That said, some asthmatic horses have allergies to pollens, making the summer months more challenging.
The horse’s respiratory tract is exposed to countless airborne allergens and dust particles in a stable. It is worth noting that even a completely healthy horse (or horse owner!) can develop airway inflammation if exposed to a very dusty environment. Airway inflammation progresses to equine asthma when a susceptible horse breathes in an allergen. Most evidence points towards fungal spores in hay and straw being the principle allergens.
The respiratory system of horses with equine asthma overreacts to allergens and the small airways go into spasm and narrow. The airways also become inflamed and produce increased amounts of mucus and inflammatory cells. Once this occurs, the horse’s lungs become hyperreactive to other irritants such as dust, ammonia from urine, and even cold air. However, the disease is reversible and, if the allergen(s) is removed, the airway will return to normal and clinical signs will resolve.
What is the treatment?
Steroids are the mainstay of treatment for horses with equine asthma, and while medical therapy is essential initially for the majority of horses, we aim to be able to maintain horses on a longer-term basis with minimal medication. For this to be successful, significant modifications to management and diet are required in order to avoid contact with the principle allergens and other irritants.
What needs changing?
With suitable medical therapy alongside allergen avoidance, the large majority of negative changes within the lungs can be reversed over a twelve-month period. While correct medical therapy is the responsibility of your vet, modifying the environment, management and diet for your horse order to avoid allergens and irritants comes down to the owner.
Good Environmental Hygiene
Many studies have shown that a major contributing factor in equine respiratory disease is the poor air quality in the stable. The main factors that relate to air quality in the stable are the quality of forage, bedding, the flooring and the ventilation.
Forage: The ideal forage will have a low level of dust and mould spores. To a degree, we can detect the dust in hay, whereas mould spores are invisible. Haylage or steamed hay are best as they contain minimal dust and mould spores. However, soaking hay is still worthwhile if steaming and haylage are not options. Full immersion in a bucket and immediate feeding can reduce inhaled dust by 60-70%.
Bedding: The ideal bedding is dust free, absorbent, inexpensive and will encourage the horse to lie down. In the past 25 years in professional racing and sport horse yards, large-chip shavings have essentially replaced straw as the first-choice bedding. However, it is worth acknowledging that low-quality shavings may contain more fungal spores and bacterial toxins than good quality straw. For horses with severe equine asthma, as little time as necessary should be spent in a stable. For these horses paper or cupboard bedding is often necessary.
Flooring: The ideal flooring is a sealed rubber floor with a built-in slope towards a drain or the stable door that is easy to clean, and reduces the amount of bedding and therefore dust in the stable. Any detectable smell of urine indicates the ammonia (respiratory irritant) levels in the stable are too high, this can be caused by poor hygiene (unsealed rubber mats, infrequent removal of soiled bedding), or insufficient/ poorly absorbent bedding.
Ventilation: Many traditional stables have poor ventilation and this can be made worse when owners shut windows and stable top-doors during poor weather. Cobwebs or dust settling in stables is a key sign of unsatisfactory ventilation. Adequate ventilation requires two openings for airflow, e.g. the top stable door being open and an open vent in the back wall. Horses with rugs on are perfectly able to cope with draughty, well-ventilated stables.
Mucking Out: Remove your horse from the stable whilst you muck-out or sweep as this generates a tremendous amount of respirable dust which will remain in the air for at least 30 minutes. Try to make sure all windows and doors are open when you muck-out and wait at least 30 minutes before putting your horse back in the stable.
Feeding: Feeding forage and hard-feed (wetted) from the floor will encourage head lowering. This allows any respiratory secretions to drain out of the windpipe and nose. Not only will this allow you to become aware of any secretions, it also avoids pooling of the secretion in the lower windpipe which increases the risk of secondary bacterial infection.
Numerous studies have displayed that horses with equine asthma experience oxidative stress in their lungs. Levels of vitamin C (a water soluble antioxidant) were measured in the lung secretions of healthy horses and those with asthma, and found to be lower in horses with asthma1. Supplementation with an absorbable form of vitamin C could support asthmatic horses experiencing oxidative stress. More recently, a study found that supplementing omega 3 fatty acids DHA and EPA reduced the signs of lower airway inflammation in effected horses2. Both vitamin C and omega 3 fatty acids DHA and EPA are included in RespirAid DHA.
1. Deaton, C. M., Marlin, D. J., Smith, N. C., Roberts, C. A., Harris, P. A., Schroter, R. C., & Kelly, F. J. (2005). Antioxidant and inflammatory responses of healthy horses and horses affected by recurrent airway obstruction to inhaled ozone. Equine veterinary journal, 37(3), 243–249.
2. Nogradi, N., Couetil, L. L., Messick, J., Stochelski, M. A., & Burgess, J. R. (2015). Omega-3 fatty acid supplementation provides an additional benefit to a low-dust diet in the management of horses with chronic lower airway inflammatory disease. Journal of veterinary internal medicine, 29(1), 299–306.