Respiratory

Any problem involving the horses' ability to breathe and absorb oxygen from his lungs has a major influence on athletic ability.   At Troytown we recognise the importance of this as a cause of poor performance. Facilities for investigation include airway endoscopy, a lunging arena, high speed treadmill video endoscopy, digital radiographs, bronchioalveolar lavage (lung wash), flowmetric analysis of lung function and full haematological, biochemical and bacteriological investigation.

Horses that make an abnormal noise at exercise can be suffering from a range of problems:

• Laryngeal Paralysis
This is evident as a whistle or roar at exercise caused by paralysis of left vocal cord of the larynx. Diagnosis is generally made by a combination of listening to the horse at exercise and endoscopy at rest. However, the definitive test is treadmill endoscopy. Some horses may scope normally at rest but show paralysis at exercise on the treadmill. There is a grading system of laryngeal function at rest. Grades 1 and 2 are considered normal while grade 3 and above will adversely affect performance. Treatment is by either a Hobday or tieback procedure depending on the severity of the condition.
• Dorsal Displacement of the soft Palate (DDSP)
This condition is know under a number of different names such as "gurgling, choking up, and swallowing the tongue". Typically a horse fades suddenly in the last quarter of a race coinciding with a very loud gurgling noise. It is usually only the jockey who hears this as once the palate is replaced the noise is no longer heard. DDSP can be caused by immaturity, infections, unsuitably heavy ground, horses galloping with mouth open and the presence of respiratory infections. Once these problems are sorted many horses will no longer gurgle or choke up. However, there are other cases which require some surgical intervention. High speed treadmill endoscopy is the only way of visualising this condition and making an accurate diagnosis. In addition there are other conditions such as epiglotic entrapment, pharyngeal collapse, abduction of the aryepiglottic folds and collapse of the corniculate processes etc. which mimic DDSP. Treadmill endoscopy can differentiate between these and point towards the most suitable surgical treatment.

There are a range of surgical procedures for correction of DDSP including thermocautery, resection of the free border of the palate, muscle resection, Ahearns procedure and more recently a tie forward operation. Not all of these procedures work in every case and there are times when repeat surgeries are needed to get desired improvement. There is a new type of collar which can be used during training which if it gives an improvement would suggest that a tie-forward operation would be beneficial.

• Recurrent Airway Obstruction and Inflammatory airway disease
These are lung problems affecting race horses. Although infection may initiate the problem or exacerbate an existing problem in general they are not cured by antibiotics. The condition causes constriction of the airways and therefore decreases oxygen getting to the lungs. It is primarily an allergic type response to allergens in the environment. They are hard to diagnose but adversely affect racing performance. At Troytown we generally lung wash horses after treadmill endoscopy to check for the presence of RAO. It is surprising how often that this reveals a problem. We have devised a sophisticated regime of nebulization therapy which is very affective in many cases.

These are some of the more common problems encountered. However there are a large range of other respiratory conditions which can be investigated and treated.

Hobday's Procedure