The horse’s airways

Horses are obligate nasal breathers, meaning they breathe in and out through their nostrils, passing the oxygen to the pharynx and larynx where the airways narrow — this is the most significant site of airway obstruction, even in a healthy horse. The air then passes down the trachea (windpipe) and on to the lungs, so this tube is the main passage for oxygen to get to the lungs. If any part of this respiratory chain becomes damaged, the system will struggle to work efficiently and correctly, causing loss of function and poor circulation of red blood cells into the muscles. Horses rely on their respiratory systems to fuel their cells’ mitochondria, which use oxygen to release energy stored in sugars and fats, so they will be unable to perform as well as they should.

Using a dust-free bedding can greatly reduce the chance of your horse developing a respiratory disorder. However, sometimes this still isn’t enough if the stable is poorly ventilated or if the bedding is not absorbing the urea sufficiently. This results in another huge problem — a build-up of ammonia, characterised by that ‘horsey smell’. Air quality in the stable is hugely compromised by ammonia as it releases fungal spores, bacteria and noxious gases. If these are absorbed into the horse’s upper airways the movement of the cilia will be compromised, leaving them unable to defend the respiratory system from foreign particles entering the lungs.

Even in a well-ventilated stable ammonia can contaminate feeds and bedding if urea is not cleaned out thoroughly. Ammonia can cause irreversible health problems that may greatly affect both horse and human performance, so it is important that you and your equine have as little exposure as possible to ammonia when in the stable environment.