Equine Asthma and Allergic Respiratory Disorder - How can we help our horses?
Following on from my last blog, about part 1 of the series of webinars by Professor Meriel Moore- Coyle, hosted by Horses Inside Out, today I would like to share with you a little about part 2 - Galloping Forward with Healthy Lungs.
In this webinar, Meriel explains the scientific and practical knowledge we need in order to understand Equine Asthma and to manage our horses both to prevent it and reduce the risk and effect in horses that suffer with the condition.
Your horse of course only has one set of lungs, and although it is possible to train the respiratory system with exercise, you cannot change the size of the lungs and once they are damaged you are unable to improve them. Therefore proactive prevention of lung damage is key.
There are 2 main causes of coughing in horses. 1. Virus 2. Allergic Respiratory Disease (Equine Asthma)
If your horse coughs, you have an issue. Horses do not ‘clear their throat’ before they speak or when they exercise like human’s do, that is not natural for them. They will only cough if they have an issue, and it’s up to us to investigate this to find out the cause.
A virus will come alongside a raised temperature and some other symptoms and should be treated by a vet.
Allergic Respiratory Disorder can only be diagnoses by monitoring your horse’ s ability to exercise and the amount of coughing they are doing.
It can then be categorised into one of 2 types:
Inflammatory Airway Disorder (IAD) also known as mild to moderate Equine Asthma (EA)
Severe Equine Asthma (sEA) formerly known as Heaves, COPD & RAO)
Some interesting facts shared my Meriel, did you know that around 80% of young thoroughbred racehorses are affect by IAD! And sEA is present in 14% of the sport horse population in Europe! These are large statistics.
So, what are some of the signs of IAD and how would you know if your horse is affected? Some common indicators include:
Poor performance
Occasional coughing (normal at rest and usually in walk & trot, may cough in trot or faster work)
Mild inflammation in the airway (this would need to be confirmed by your vet)
Excessive mucous in the trachea
No airway remodelling - this means that your horse can recover from IAD if you can remove the agents in the air that the horse is allergic to
Horses with IAD do not automatically develop Severe Equine Asthma but they do have an increased risk. So diagnosing this early and putting measures in place to help the horse can prevent this from happening.
Now let’s look at some of the signs of sEA (full blown Equine Asthma as Meriel describes it)
Coughing & increased mucous secretion
Exercise intolerance (working these horses can also put tremendous strain on the heart)
Respiratory stress at rest
Marked lower airway inflammation (it is possible to reduce or even reverse this if you catch it early)
Heave lines (often seen in chronic cases where the horse is engaging their abdominal muscles to help them with expiration)
Airway remodelling, thickening of the trachea, alveoli full of mucous (this is more serious)
So what are some of the causes of these airway disorders?
The main cause is Airborne respirable dust (ARD) particles, and these mainly come from your hrose’s forage, bedding, management (e.g sweeping or blowing in the yard) and environment (e.g roads, trees, fields).
Meriel goes in depth into the profiling of allergens and what it is that horses are actually allergic to. Including moulds, arthropods & pollens. She is the best at sharing and explaining the science and the research studies, so definitely a reason to check out the webinar!
One really interesting fact from a study conducted by Meriel herself and one of her students at Nottingham university was that horses can react to latex allergens (just like humans can). Latex allergens come from rubber. Merial says this should be a consideration if your horse lives near a road as some particles could be coming from the car tyres, and also consider exposure to arena surfaces containing rubber.
Ultimately though the clear message Meriel sends during this webinar is that Equine Asthma is a very common issue in the horse population, and although it is possible to help with symptoms very short term with a course of corticosteroids from your vet, ultimately this a condition that relies on us as horse owners to adapt our horse management in order to protect the horse from the airborne respiratory dust that is affecting them.
So we have a diagnosis, now what can we do?
Here are just a few of the points shared in Meriel’s presentation, to help us reduce Airbourne respirable dust in our horse’s environment.
Look at your forage. 55% of all UK horse owners feed hay. But even good quality hay is potentially allergenic. Dustiness in hay is mainly related to the harvesting conditions and not the types of grasses. If you feed hay you can reduce ARD by soaking or steaming.
Soaking for just 10 minutes is optimum and reduces respirable particles by 99%
Make sure to weight the hay net down so it is completely submerged in the water
Any longer and you will reduce the nutrients in the hay and also increase the bacteria numbers
Did you know that the post soak effluent (water left over after soaking hay) is a biological hazard! It must not be disposed of down drains, it should be put on the muck heap. It is full of water soluble carbohydrates, nitrogen & bacteria which are the things that grab oxygen out of water and could kill marine life if it got into the waterways. It is also really important to change the water and use fresh water for each hay net you soak.
High temperature steaming for 50 minutes is the current best way to reduce ARD in hay and will not reduce the nutrient content of the hay, whilst also dramatically reducing the mould & bacteria content of the hay
Steamed hay is much more palatable to horses than soaked hay.
High Temperature steaming in a Haygain Steamer consistently reduces ARD by 99% and bacteria and mould by 95% so is the gold standard currently
This is due to the spikes in the steamer and the way the steam goes into the hay and differs from many other steamers on the market or home made steamers.
If you must feed dry hay, in a hay net is probably the worst for ARD, as when the horse pulls in the hay net it causes the dust to fly off into the air. Dry hay in a feeder such as a Haygain Forager or off the floor is better in this respect. Or feed outside if you can rather than in the stable.
Ventilation should also be a big consideration when feeding hay, both in your stable environment and also in your lorry or trailer. And in an American barn type stabling, you also need to consider what your neighbour’s dust management is like, not just your own.
Feeding haylage is of course another option for low dust (not dust free) forage, but it does contain higher pollen levels and has a short shelf life once the bale is opened. Haylage can also be very nutrient dense which needs to be a consideration if your horse is a good doer, as you need to feed enough to satisfy their chewing criteria & digestive tract needs (see last week's’ blog) whilst not over supplying their energy needs.
Look at your horse's stable environment. Bedding such as straw can be very dusty. And deep litter beds of any type are a breeding ground for bacteria & production of ammonia.
Dust extracted shavings really are best. Although when you open the bale you may see dust in the air, these particles that you can see are too large to enter the lungs. Also consider walls, roofs and ledges in your stables. Wiping the walls and hoovering the cobwebs etc will be very beneficial for your horse in terms of reducing the ARD which attaches to everything in it’s environment. This can easily be pushed into the air by a gust of wind, or even when throwing a rug over your horse.
Look at your horse’s field environment. Coughing at pasture is also known as SPAOPD or Summer Pasture Obstructive Pulmonary Disease, and is most likely caused by tree & grass pollens. Symptoms are very similar to sEA. Can you keep your horse in a stable during high pollen times? Are you able to move them to a different field? Or even put a screen up between them and the trees that may be affecting them?
Consider adding supplements or therapies. Meriel is very clear during this presentation that management really is the key to preventing and managing Equine Asthma, however there are a small amount of supplements that may give some relief.
A potent blend of essential oils including Eucalyptus, Menthol and Peppermint can help maintain clear, healthy airways
Omega 3 fatty acids can help as they are anti inflammatory - Linseed oil is a good source of Omega 3 fatty acids.
Salt therapy in a nebuliser or using a nebulising system can be useful to help break down mucous in the lungs and help clear them
My blog really is only touching the surface of the information Meriel has shared in this webinar. Whether your horse has a respiratory condition that requires management, you are looking to prevent a respiratory condition in your horse, or you run a yard where you are looking to implement the very best practice for the horses in your care when it comes to respiratory health, I highly recommend checking this out!
The next webinar in the series with Meriel is titled ‘Healthy Gut, Healthy Horse’ and will be looking at feed releated metabolic disorders such as EGUS, Colic, EMS, Laminitis & PPID. So promises to be another fascinating presentation, can’t wait!
Thank you for checking out my blog.
Jess