"My horse suffers from Heaves"
"Mine has Broken Wind"
"Or is it Chronic Obstructive Pulmonary Disease"
"Small Airway Disease (SAD)"
"No, my vet said Recurrent Airway Obstruction (RAO)"
"Inflammatory Airway Disease (IAD)"
"Nope now it’s Equine Asthma!"
Numerous terms and abbreviations have been used over the years describing a variety of inflammatory and hyper reactive airway conditions which cause coughing in horses. Two people can be talking about the same condition but under different names resulting in much confusion so this article aims to pick through the names and terminology used and explain the latest terminology.
In 2016 a panel of respiratory experts got together to discuss this very conundrum and review what we know and areas of further research that are needed. The group of specialists led by Laurent Couëtil, DVM, PhD, head of Large Animal Internal Medicine at Purdue University, released a new consensus statement which proposed that these various syndromes are characterized under the umbrella term Equine Asthma.
The term COPD is no longer used to describe this condition in horses because many aspects of the disease are different from human chronic obstructive pulmonary disease. In humans, COPD is mainly a consequence of cigarette smoke and is characterized by structural changes within the lung that are absent in the horse.
Dr Laurent Couëtil explains “While the terms ‘recurrent airway obstruction’ and ‘inflammatory airway disease’ are descriptively accurate, they are not necessarily terms that immediately help the horse owner to understand the disease process and so ‘equine asthma’ has been adopted.”
Like human asthma, equine asthma is triggered by inhalation of dusts that contain allergens and other irritants, and like human asthma, the cough and difficulty breathing can be reversed in the short-term by medications, often delivered by inhalers, or in the long-term by removal from the offending dusts.
Dr Laurent Couëtil
The new classification implies that horses with similar clinical presentations (such as chronic cough, excess mucus, poor performance) can vary widely in terms of disease severity. However, horses with IAD/mild Equine Asthma do not necessarily develop Severe Equine Asthma over time. Although Bosshard and Gerber (2014) found horses with mild respiratory clinical signs have an increased risk of developing Severe Equine Asthma it is not always the case.
So, what is the most up to date terminology to use?
What were previously referred to as Inflammatory Airway Disease are known as Mild-Moderate Equine Asthma while the classic RAO/Heaves horse is described as Severe Equine Asthma.
How can Haygain help?
The Haygain method of high temperature steaming is scientifically proven to reduce respirable dust by up to 99% and kills bacteria, mould, fungal spores and yeast. Where does your horse spend the majority of his time in the stable...eating…with his nose in his hay!
Providing steamed hay will minimise exposure to respirable dust including mould, fungal spores and bacteria from one of the major sources of the stable environment. Whether you are managing an existing case of Equine Asthma or your horse is healthy they would all benefit from less exposure to these allergens, irritants and dust particles.
Remember they would not encounter, certainly not in such high concentrations these while outside of the stable, eating grass.
In a recent study horses fed steamed hay from a Haygain hay steamer were found to be 65% less likely to develop IAD!
What else can I do to improve the stable environment?
Ventilation- make sure the stable is well-ventilated with open windows or doors (with a chain across) and openings at the roof.
Storage- store hay and straw as far away from horses as possible (especially if they have Equine Asthma) preferably in a different building.
Cleanliness- use a low dust bedding option and avoid straw if possible. Hoover cobwebs and clean/disinfect regularly. A sealed, padded rubber flooring will allow less bedding to be used, more regular cleaning and prevent ammonia build-up seen in stables with traditional style mats or deep litter bedding.
Take home message:
So, you just need to use the term Equine Asthma to be correct but be aware of the spectrum and different variances on the condition.
Bosshard S, Gerber V. Evaluation of coughing and nasal discharge as early indicators for an increased risk to develop equine recurrent airway obstruction (RAO). J Vet Intern Med 2014;28:618–623.
Couëtil, L. , Cardwell, J. , Gerber, V. , Lavoie, J. , Léguillette, R. and Richard, E. (2016), Inflammatory Airway Disease of Horses—Revised Consensus Statement. J Vet Intern Med, 30: 503-515. doi: 10.1111/jvim.13824