Cornage in horses is a condition of the upper respiratory tract in which one of the vocal cords and the associated arytenoid cartilage in the larynx no longer function normally. This condition is also known as laryngeal hemiplegia or recurrent laryngeal neuropathy (RLN) and, in most cases, affects the left side.

In a healthy horse, the larynx opens fully during exercise, allowing sufficient air to flow through the trachea to the lungs. The muscles surrounding the larynx ensure that the vocal cords and arytenoid cartilages are pulled outwards, clearing the airway. In cornage, the recurrent laryngeal nerve – the nerve that controls one of these muscles – is affected. As a result, the associated muscle functions less and less effectively and may eventually lead to partial or complete paralysis. The arytenoid cartilage cannot then open sufficiently, causing the airway to remain narrowed.

This narrowing can cause symptoms, particularly during exercise, when the horse needs more oxygen. A horse with cornage, also known as a ‘corneur’, often makes a characteristic whistling, wheezing or rattling breathing sound. Depending on the severity, cornage can also lead to reduced stamina and a decline in performance.

At Dierenkliniek Den Ham, we can examine your horse for cornage and assess the extent to which the airways are obstructed. Based on our findings, the severity of the condition and your horse’s intended use, we will advise you on the most appropriate treatment. If surgery is required, we will discuss the options with you in detail.

The most recognisable symptom of cornage is an abnormal breathing sound during exercise. This is often described as a whistling, screeching or wheezing sound. At rest, horses with cornage are often asymptomatic, which means the condition is sometimes only noticed during more strenuous work.

As well as an abnormal breathing sound, a horse with cornage may tire more quickly, have less stamina or perform less well. In more severe cases, the narrowing of the airways can lead to obvious breathing difficulties during exercise.

Possible symptoms of cornage include:

An abnormal breathing sound does not automatically mean that a horse has cornage. Other upper respiratory tract conditions can also cause similar symptoms. A proper diagnosis is therefore important.

If a horse is making an abnormal breathing sound or if there is a suspicion of cornage, further investigation of the upper respiratory tract is required.

An important part of the diagnosis is an endoscopy on the horse. During this procedure, the vet inserts a thin, flexible camera tube through the nose. This allows the throat, larynx, vocal cords and the movement of the arytenoid cartilages to be examined.

This makes it possible to determine whether one side of the larynx is not functioning properly and to what extent the airway is obstructed.

As cornage can cause symptoms particularly during exercise, it may be useful in certain cases to assess the airways whilst the patient is exerting themselves. Dynamic endoscopy can be used to visualise the functioning of the upper airways during exercise.

Based on the results of the examination, the severity of the abnormality can be assessed and the most appropriate treatment determined.

If an examination reveals that your horse has cornage, the appropriate course of action depends on the severity of the condition and the symptoms the horse is experiencing.

Not every horse with cornage needs immediate surgery. In mild cases where the horse experiences few or no symptoms, monitoring or adapted management may be the preferred option in some instances.

Where airway narrowing leads to obvious breathing difficulties or a decline in performance, a cornage operation may be considered for the horse. In making this decision, we take into account not only the degree of paralysis, but also the horse’s intended use, age and general health.

The most common surgical treatment for cornage is laryngoplasty, also known as a tie-back operation. The aim of this operation is to permanently widen the airway.
During laryngoplasty, the paralysed arytenoid cartilage is fixed in a more open position using strong sutures. This creates more space in the larynx, allowing more air to flow towards the trachea and lungs during exertion.
In certain cases, laryngoplasty may be combined with a ventriculectomy and/or cordectomy. This involves removing tissue from the Morgagni pouches and/or the affected vocal cord. The aim of this is to further improve airflow and reduce abnormal breathing sounds.