16/08/2026
Ive had the worst flu of my life this past month, and it reminded me of our horses suffering with respiratory conditions:
🌬️ Is your horse coughing, struggling to breathe or just not performing like they used to?
Respiratory disease in horses can be subtle — and sometimes the first sign is simply that your horse is not quite themselves under saddle.
What we now commonly refer to as Equine Asthma Syndrome includes conditions such as Inflammatory Airway Disease (IAD), Recurrent Airway Obstruction (RAO) and Summer Pasture-Associated Obstructive Pulmonary Disease (SPAOPD).
These are chronic inflammatory conditions affecting the horse's airways and can lead to:
🐴 Recurrent coughing
🐴 Excess mucus production
🐴 Reduced performance
🐴 Exercise intolerance
🐴 Increased respiratory effort
🐴 Wheezing
🐴 In more severe cases, laboured breathing and weight loss
🌿 What causes it?
The horse's respiratory system is constantly exposed to what is in its environment.
Dust, mould, fungi, pollen, spores, bacteria, endotoxins and ammonia can all contribute to airway irritation and inflammation.
And it's not just the stable environment.
Some horses can react to environmental pollens, including grass, weeds, trees and other plants.
In my work as an equine nutrition advisor, I commonly see horses where respiratory problems appear to be associated with environmental pollen exposure, including exposure around pine trees.
🐴 Why are horses so susceptible?
Horses are obligate nasal breathers, meaning they breathe through their nose rather than their mouth.
Their upper respiratory tract normally filters much of what they inhale, but very small particles can travel deep into the lower airways.
In susceptible horses, exposure can trigger an exaggerated inflammatory response.
The airways can then become narrowed because of:
• Inflammation and thickening of the airway walls
• Constriction of the bronchial muscles
• Excess mucus production
• Accumulation of inflammatory cells within the airways
The result? ➡️ Less room for air to move.
🏠 Stable management matters!
One of the biggest risk factors is exposure to dust and airborne particles.
Hay can be a major source of respirable dust, particularly when it is dusty, mouldy or poorly stored.
Round-bale hay and poor feed hygiene can also increase respiratory exposure.
Practical steps that can help include:
✅ Maximise turnout where appropriate
✅ Keep stables well ventilated
✅ Open doors and windows to encourage airflow
✅ Remove dusty or mouldy feed
✅ Keep bedding clean and low-dust
✅ Avoid sweeping while horses are inside
✅ Feed good-quality, hygienic forage
✅ Consider soaking or steaming hay where appropriate
✅ Feed forage off the ground where practical
✅ Provide fresh, clean water at all times
Hay steaming can dramatically reduce mould and microbial contamination, making forage much more hygienic for horses with respiratory sensitivities.
🌾 But what about pasture?
Pasture doesn't automatically mean "dust-free."
Some horses can develop respiratory reactions to environmental allergens, including pollen.
SPAOPD is particularly interesting because affected horses are often kept at pasture and may experience worsening signs during periods of high temperature and humidity.
So if your horse is coughing or struggling to breathe during certain seasons, don't automatically assume it's "just a bit of dust."
🚨 Know the warning signs
Respiratory disease can be subtle.
A horse with IAD may have:
• Occasional or chronic coughing
• Reduced performance
• Less willingness to work
• Excess tracheal mucus
A horse with more severe airway obstruction may develop:
• Frequent coughing
• Increased respiratory effort
• Laboured breathing
• Wheezing
• Exercise intolerance
• Weight loss
And if your horse develops severe difficulty breathing, marked nostril flaring or open-mouth breathing, this is an emergency requiring immediate veterinary attention.
🔬 Diagnosis matters
Respiratory problems can have many causes, and coughing alone doesn't tell us exactly what is happening.
Your veterinarian may use history, clinical examination, endoscopy and respiratory tract sampling to investigate the problem.
🥕 What about nutrition?
The following specific nutrients can further support healthy toxic processing and elimination to provide support for the detoxification systems, support the respiration and lung function.
A balanced diet providing adequate vitamins, minerals, antioxidants and essential amino acids can support normal immune function, antioxidant defences, liver and respiratory health.
Key nutrients include vitamin E, vitamin C, selenium, zinc, copper, magnesium, B vitamins and methionine, while compounds such as MSM, acetyl-L-carnitine and CoQ10 may provide additional antioxidant and cellular support.
Herbal and nutraceutical support:
Some herbal ingredients, including echinacea, liquorice, chamomile, thyme, elecampane, ginkgo, jiaogulan and spirulina, have traditionally been used to support immune and respiratory function. Other antioxidants such as grape seed extract, citrus bioflavonoids and CoQ10 may also help support antioxidant protection.
For horses with ongoing respiratory problems, supplementation should be considered alongside veterinary diagnosis, environmental management and an appropriate diet, rather than as a replacement for treatment.
That means looking at the whole environment:
🌿 Pasture
🌾 Hay
🏠 Stable
🛏️ Bedding
🌬️ Ventilation
🌳 Environmental pollen
💨 Dust and airborne particles
And remember — "it's just a cough" isn't always just a cough.
If your horse is coughing, has unexplained poor performance or seems to be working harder to breathe, it's worth investigating.
💚 Healthy airways are essential for a healthy, happy and performing horse.
