You’ve heard of “winter cough” or “stable cough”. You wonder if it’s caused by a draft or a virus. Winter has special respiratory challenges.
◆︎ Outdoor housing:
Although you may have heard that outdoors is best for your horse’s respiratory health, it still has its challenges.
➡ Cold dry air: When a horse inhales, the respiratory mucosa warms the air and adds humidity. This can cause drying out of the mucosa, with the cilia unable to remove the debris effectively. This allows particles to become trapped in the lower airway.
➡ Bronchoconstriction: Cold air can also cause bronchoconstriction of the airways.
◆︎ Indoor housing:
To combat the cold, many people have enclosed barns. While this can reduce the heat loss in the horse, it exposes the horse to contaminants in the barn.
➡ Ammonia: This is a common problem in barns. It is a respiratory irritant. One of the problems is that ammonia gas is heavier than air. While you may not detect a strong odor while standing, the concentration is much higher at ground level. This affects horses when they lay down to rest.
Ammonia negatively affects the lining of the lungs. It damages the lung epithelium and the cilia to become less effective in removing debris. Additionally, it causes swelling of the airways and inflammation of the mucous membranes.
➡ Dust: We all know that hay and dust is common in barns. This is also a respiratory irritant.
◆︎ The particles we don’t see
Dust particles are usually larger than 10 microns. We can see the dust. These particles are usually heavy enough that they are trapped by the mucosa in the nose and throat.
➡ The danger lies in the smaller particles that we can’t see. These are particles usually under 5 microns. Because they are small and light weight, they frequently get inhaled deeply into the lungs. There, they cause tissue inflammation.
◆︎ Supplements to support your horse
N-Acetyl Cysteine: has a dual mechanism of action. It is a mucolytic, thinning the mucus, so that particles are more easily expelled. It is also an anti-oxidant, helping to replenish glutathione. This helps protect the lungs from oxidative stress caused by dust inhalation.
Spirulina: This supplement has been shown to be an antihistamine. Ordinarily, in response to dust and allergens, histamine is released from mast cells. Spirulina helps inhibit the release of histamine, which may help relieve some of the breathing issues.
Jiaogulan: Jiaogulan can increase the production of nitric oxide. This is a vasodilator, but also a bronchodilator. This can help support the horse while breathing cold winter air.
MSM: This anti-inflammatory inhibits the NF-kB pathway. This helps reduce the inflammatory damage that occurs with airborne particles and the irritating presence of ammonia. It can help support the horse by potentially reducing the severity of inflammatory processes.
◆︎ Final note:
While supplements are helpful, it’s important to remember that environmental control is also important.
▪ Reducing the dust and ammonia in the barn is critical to good respiratory health.
▪ Clean fresh water is also important to assist in keeping the respiratory tissues hydrated.
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Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay, MSc. 2026