Equine Asthma Syndrome

Navigating and understanding the terms used to describe Equine respiratory diseases such as ‘Heaves’, Recurrent Airway Obstruction (RAO) or Chronic Obstructive Pulmonary Disease (COPD) and Inflammatory Airway Disease (IAD) has always been a bit of a nightmare not just for our clients but for professionals as well. We now recognise these diseases in much simpler terms that make them easier to understand and manage. The term ‘Equine Asthma Syndrome’ is now increasingly used to describe the common airway diseases in horses that are a result of chronic exposure to inhaled dusts and allergens.
Some of the common signs of disease are:

1. Poor performance or poor recovery after exercise
2. Chronic cough particularly during exercise
3. Increased breathing rate at rest
4. Nasal discharge

Diagnosis of the condition is currently based on an endoscopic examination as well as collection and analysis of fluid samples taken from the trachea (windpipe) called a ‘Tracheal Wash’, often in combination with fluid taken from the lungs called a ‘Lung Wash’. Laboratory analysis of these samples helps us identify the degree and type of inflammation present and also allows us to rule out other conditions such as infections, exercise induced pulmonary haemorrhage (bleeding), parasites and tumours. The information obtained from these samples is critical to us formulating an effective treatment or management plan. This procedure is very commonly performed in our practice under sedation. Whilst mostly experimental at this stage, in the future, measurements of Lung Function are likely to become more commonplace and a useful tool in diagnosing these conditions.
Treatment of the condition is based on reducing the amount of dust the horse inhales in combination with medications to reduce the inflammation, increase mucous clearance and reduce airway constriction.
Minimising environmental dust can be done in the following ways:

1. Avoid stabling by housing horses outside or stable in well ventilated sheds
2. Avoid straw bedding and opt for wood shavings or paper based ‘low dust’ bedding
3. Avoidance of hay by substituting for pelleted feeds.
4. Feeding on the ground to facilitate mucous clearance

Recent studies have shown promising results with the addition of  omega-3 fatty acid supplements to the horses diet, in reducing airway inflammation through immune system modulation.