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WORKING THE HORSE WITH A NASAL DISCHARGE

Dr McGregor's Equine Blood Analysis Series

One of the most frustrating aspects of training and owning horses in work is the nasal discharge and the cough. Normally we can break these into the following groups - problems, complications and treatment. We won't include bleeding problems in this article.

1)   Young horses (yearling to three year olds) with clear discharges.

These discharges are caused by local inflammation to the nasal linings with the sinuses and throat sometimes involved. A cough usually means the throat (pharynx and/or trachea) is involved. The causes of the discharge in order are:-

Allergic irritation
Teeth
Viruses
Chemical irritation
Physical irritation eg. seeds

To determine the cause, inspection of the nasal lining, palpitation of mouth and blood tests will indicate the main cause. For allergies and irritations, the use of nebulisers or oral treatments such as Ventolin, will usually control the problem. Damp feeds, cap removal and, if allergies are a real problem, RAST testing can all help as well. Usually the horse can be worked through the problem. Appetite reduction is helped by the use of the Neb or Ventolin.

If the problem persists longer than two weeks, and if a virus is not evident on blood tests, the usual complication is that the horse has developed pharyngitis. This is similar to human tonsillitis but the horse has about 600 small tonsil-like areas compared to our two and when they are activated, they cause the throat area to become very sensitive to contact from food, cold water, dust, cold air and usually a cough is elicited. Pharyngitis is easily seen with a fibre-optoscope and medical treatment usually means the horse can be kept in full work. These horses are often diagnosed as having throat conditions such as roaring and soft palate damage and may undergo unnecessary surgery or early retirement.

Probably the biggest problem with young horse pharyngitis is that the trainer does not like working a horse with a cough and then some horses start to tense their throats and islocate their soft palates because of the inflammation. However, working horses can still perform with chronic pharyngitis, as 2 and 3 year olds Balmarino, Yir Tiz and Sovereign Red have shown.

The use of Nebs has made controlling this problem well within the bounds of most stables.

2)   Older horses (4 years plus) with clear discharges

Again caused by local inflammations but in order of cause are:-

Virus
Allergy
Physical irritation

Check these out first for viruses. Remember, with most of the upper respiratory viruses in WA, the horse can stay in light work for ten days and then is okay to return to speed. Again, if allergic or irritation, nebs are very useful.

3)  Young horses (1, 2, 3 years) with coloured discharges

These are nearly always sinus problems with the exception of foreign bodies (eg. grass seeds) and turbinate (small nasal bones) fractures or abcesses. Sinuses in young horses are activated by the movement of teeth. Major movements occur at about 18 months, 0 months and 36 months of age and as the teeth originate in the sinuses, their movement down into wear causes production of space and, often, inflammation in the sinus spaces. Bacteria are favoured by these events and they find the sinuses an excellent areas to grow. The body pumps in the pus cells to control the bacteria and we have the pus build-up that leads to the coloured nasal discharges. Usually, the discharges are coming from the frontal sinus running into the throat area and pushed out the nose bilaterally. The discharge can be from the maxillary sinus which opens into each nasal cavity so the discharge is only on one side. Viruses can also inflame the sinuses but it is bacterial infection which stimulates the pus production.

Treatment of coloured discharges involves elimination of any viral remnants and then aim to flush out the sinuses. This is best done with a liquefying medication such as Bisolvon or Sputolysin combined with heat. The best heat production is to work the horse and, during post work clean-up, to put a warm, wet towel over the bridge of the nose to add heat to an already warmed up head. A neb can be used to relieve the throat if there is a cough. These horses are best worked through rather than spelled. The candlestick-nosed colt you put out in April will usually still have a sinus discharge when he comes back in August.

4)  Older horses with coloured discharges

These are still usually sinuses but may indicate an impacted tooth or damage to the turbinate bones from a kick or fall. These horses are usually best scoped to diagnose the problem. I have seen everything from grass seeds to cancer.

In the climate we train in, in the South-West of Western Australia, we have very few of the major debilitating respiratory problems as seen in the tropics or in areas where horses need to be housed over winter and in most cases, other than viruses, most horses can be worked through a problem. We all still need to think of the individual attitude of the horse, the stage they are in and how far we want to go in this prep when deciding how we treat the nasal discharge. However, it can often be treated successfully and, in a game where respiratory injury downtime is about equal to lameness, we can keep horses going with a little knowledge and management.