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Respiration / Pollens /Chronic Coughing

Principal Body System: Respiratory

Definition: The lungs and a series of associated passageways leading into and out of them

Function: Supplies oxygen; eliminates carbon dioxide, helps regulate the acid-base balance of the body

The equine respiratory system is geared for athleticism. With a huge lung capacity to enable air-intakes of up to 1800-litres/minute in a galloping horse, up to 300-litres of blood are pumped at high pressure at full gallop through tiny lung capillaries surrounding 10-million air-sacs, to take up and deliver over 70-litres of oxygen, per minute, to the working muscles. Phew!

As a result, any related condition that reduces efficiency of oxygen uptake from the air sacs can significantly influence a horse's athletic capacity. As fate would have it, in domesticity the equine respiratory system is continually being challenged from the external environment, i.e. stable moulds/allergens, school surfaces, dusty bedding, pollens, feed - you name it, our horses will breathe it in.

Seasonal allergies are something we’re all familiar with, human or horse, whether we're personally affected or not - and they’re rising in prevalence. Allergies occur when the immune system reacts to substances in the environment, making antibodies that trigger mast cells to release histamine, causing those all too familiar symptoms like itchy watery eyes and nasal congestion.

Conventional treatments may help reduce symptoms temporarily, but they often include inhalers/steroids which can be detrimental to the immune system, and most importantly, don’t address the root cause of the immune dysregulation.

Inhalers are steroids – you take the inhaler, you flood the body with steroids, and their purpose is to imitate the adrenal hormones, in this case cortisol, and specifically cortisol’s role in the fight/flight response.

When there’s a fight/flight (cortisol) survival response, the bronchial passageway dilates, the blood flows to the muscles (to Run!Fast!Now!) and to the brain (to stay focused on the perceived ‘threat’); the pupils dilate (tunnel vision to stay focused), and the lungs open up so more oxygen can get in to support the Run!Fast!Now!

Unfortunately, if steroid inhalers are used long term, we get side effects, mainly problems with the endocrine system and the central nervous system, both of which affect the adrenal glands. Far better to go natural and use herbs which naturally open the airways, i.e. eyebright (Euphrasia) and liquorice (Glycyrrhiza).

Back in the good old days, COPD was the only known respiratory term, previously thought of as a winter syndrome when horses traditionally spent a lot of time stabled. These days? We’re now seeing allergen reactions pretty much all year round, with spring tree pollens causing a distressing histamine intolerance, followed by our hot and humid summers presenting deeper congestion from the grass pollens.

The warm, humid air holds more pollen particles, meaning a higher pollen count, with dust and heat-loving moulds also playing a part. This puts real strain on the body's natural filtration/detoxificatin system - the liver, kidney and lymphatics - as collectively these 3-Amigos work tirelessly to clear the congestion, .

Like us humans, some horses react, some horses don't. For those that do, whether horse or human, experiencing the irritations of respiratory pollen allergies is a frustrating, debilitating syndrome that causes real misery.

The Gut:Airway connection

From Traditional Chinese Medicine (TCM) we’ve also known for a long time that the hindgut and lungs belong to the same element, specifically metal. Researchers in a couple of studies during 2020 took a closer look at the hindgut and found a physiological link between the hindgut and the airway system. The studies showed that when the hindgut microbiome function is disturbed, horses are prone to developing chronic cough issues, and when you start restoring the hindgut microbiome, the airway function improves. See our KPU page for the full story on this connection.

There's plenty we can do to support the microbiome to regenerate a better colonisation of the appropriate microbes, i.e. there could be a bit of dysbiosis going on in there, a bit of leaky gut going on, so a gut clean-up to help weed out the bad and bring in more of the good bugs may help.

Equally, the forage we feed has a huge impact on the health of those hindgut fibre-fermenters - the horse is nothing more and nothing less than a hindgut fibre-fermenting machine, so our fresh, neon-green UK grass is a nightmare as there's zero fibre in it; haylage is even worse as in order to turn cut grass into haylage it needs lactic-acid bacteria, which when eaten by the horse instantly drops those LA bacteria straight into the hindgut - cue hindgut acidosis and boom - autoimmune syndrome.

Hay really is the best forage we can feed our horses, as it's cut from long, stemmy grass, and it's the stems that contain all the equine-appropriate fibre, hence why, in the perfect world (but who lives there?!) our horses should be on only hay 24/7!

Food for thought, literally, so maybe worth checking your feed regime from feedbowl to forage. We've got this all covered in our 'Feeding our Horses' section, and specifically the 'Why what we feed has to be right' page.


We ourselves have had our fair share of allergic reactions in our herd over the years but it was our elderly show cob, Kelso, who had a problematic allergic response to just about everything life could throw at him. He had chronic sweet itch, he was a violent headshaker during pollen season, spring or summer regardless, and his respiratory system was permanently compromised.

Kelso was a classic all-pollens reactor, with the spring pollens driving him to the point of violent headshaking. If we were out hacking and I got the time a little wrong (I always endeavoured to go out first thing in the morning while the air was still cool), I'd have to dismount and he'd literally bury his face into my back for the rest of the walk home, to try and stop the irritants in the air getting up his nose and driving him crazy.

Come summer and our muggy heat, Kelso literally couldn't breathe. We had to bring him in during the day to get him out of the humidity, and out only at night when the air was cooler. Over the years I learned to manage his symptoms, but I never really understood the How&Why of the syndrome until I began studying Functional Medicine.

It was all due to Kelso, and our desperate need to find something that actually worked to help him, that sowed the EquiNatural seed - see the full story in About.

The How&Why behind pollens

Chest infection? Obvious. However, certainly for a pollen allergy response, it's all down to an over-reaction by the body's immune system (although recent science has now identified it as a much Bigger Picture - see two para's down). So, while a fairly swift fix can be sought by blocking the histamine and associated symptoms, we'd rather not end up with scripts of inhalers, steroids and inappropriate antibiotics (pollens aren't bacteria!), which not only kill off the vital integrity of the microbiome which suppresses and inhibits the immune system, but also add to the body's toxic load, which weakens the immune system further. And all without addressing the root of the problem to boot.

We all know that the immune system is the body's defense system to help fight infection, toxins and aliens from Mars. However, with an allergic reaction, the invader isn’t necessary a harmful substance - an out-of-balance immune system identifies a pretend invader when it is not, and so the killer army of white cells (lymphocytes) are given the wrong instruction to head off to fight something they shouldn't, causing the adverse reaction.

Now to that Much Bigger Picture I mentioned above, and it's a new label - histamine intolerance. These days there's too much histamine going on out there, and it's making many already-established health syndromes even worse, with humans and horses alike suffering all the more.

Histamine intolerance

Histamine in the right balance is the body’s friend, released when there's an allergic reaction. Simples. We know this. Histamines are a bit like a club's bouncer on the door, helping the body get rid of something that's bothering it, as in an allergy trigger - histamines start the process that hustles those allergens out of the body or off the skin.

However, these days, in our modern world and modern environment, histamine intolerance is now a Big Thing - too much histamine is being made by the body which causes its own allergic response, and makes the body feel seriously crap. The symptoms can be anything and everything from swelling to fluid retention and so much more, one of the reasons why so many owners see puffy leg swelling during the pollen season (more on this later). Histamine intolerance is so prevalent that it's now recognised as a spectrum illness, with mild, moderate and severe levels to it.

As it happens, when histamine intolerance crossed my path (early Feb'21), I wrote an in-depth Blog post on it - timely, as we were literally around the corner from the 2021 spring pollens ready to hit our horses. Here's the link if you're wanting the full story - https://equinatural.co.uk/i/histamine-intolerance-the-new-kid-on-the-block


Coughing is a perfectly normal healthy reflex the body uses to clear airways of irritations, i.e. bacterial/viral microorganisms, via mucous, the lungs' natural secretion. Sadly there's not a lot we can do to prevent these organisms getting in there, but we need them shifted out before they start replicating and turning into an infection.

It’s that coughing reflex which agitates the mucous out of the lungs, hence it's never a good idea to try and suppress a cough; what we should be doing is making that expectoration - the capacity to bring mucous up – as effective as it can be, as it's an important part of the process - see our Online Shop link below.. However, what if it's chronic, ongoing coughing?

Chronic ongoing coughing

If your horse has a chronic ongoing cough, and is resistant to meds yet not typically 'allergic', we should always ask Why is our horse doing this?

The wild horse is naturally used to dry, dusty environments – a horse can manage this perfectly well as normally, the cellular epithelium level in the airways is covered with a thick mucous layer which binds to the dust and shifts it out again – no cough required.

To build this mucus layer the horse needs enough cysteine – an amino acid that contains sulphur, so to build up enough cysteine the body needs enough sulphur. Cue a possible KPU connection.

When there’s KPU the horse goes into sulphur-deficiency so the airways can’t build up enough cysteine; thus they can’t build up the mucous layer so the airway is dry. Dust is inhaled and the horse coughs. Cue a major Serious MisUnderstanding. One method us carers do is turn to haylage instead of hay – well, it’s dust-free innit! Well, yes, but … while this is our well-meaning attempt at alleviating the symptoms, haylage significantly damages the gut microbiome, which completely runs the immune system, so it triggers the autoimmune response which increases allergic reactions – moulds, pollens, insect bites …

This is always a secondary reaction – we should always track back to the root cause – is it hindgut dysbiosis causing B6 disruption, causing liver biotransformation disfunction, causing KPU? All covered on our KPU page.

What to do

Taking the functional approach, we need to ensure that the immune system is as healthy as it can be, alongside toning the Lymphatic System, upon which the lungs (and skin) rely on to drain the toxins away. If you read the Histamine Intolerance blog post you'll see that the lymphatics are very connected to the Big Picture, as when the body is having an allergic reaction and the immune system is not up to par, the lymph nodes will be overburdened and swollen, which will have a direct effect on the lymph, the lymphatic system's fluid, not draining the congestion away properly.

Immunity starts with the gut, but everything begins with the microbiome which is where the immune cells are both created and housed, so a key strategy involves keeping the gut healthy and maintaining beneficial gut microbe levels. An unhealthy, inflamed gut won't keep the immune system strong enough to fight off potential allergens.

As the saying also goes, "Take out the bad and put in the good," so check what you're feeding, from feedbowl to forage, as there may be food allergens triggering a response:

  • Eliminate common feed triggers like wheatfeed, corn, soy, alfalfa, GMO, food additives and so on, so check your feedbag ingredients. See our Why what we feed has to be right page for more info on these pro-inflammatory fillers.
  • Feed a clean, high-fibre, very low-carb diet, adding in anti-inflammatory omega-3 plant nutrients such as linseed.
  • If you're feeding haylage, sorry but Don't! All covered here - https://equinatural.co.uk/i/haylage-why-we-shouldn-t-feed-it
  • Check for other environmental causes such as pesticides, chemicals, pollution, moulds - is there local crop-spraying going on nearby?
  • Are there, or have there been, any chronic infections such as viruses, bacteria, yeasts or parasites?
  • Has your horse recently been on antibiotics/bute or any other vet meds? If so, consider giving your horse's liver a reset.
  • Reduce stress and ensure there's adequate rest - a stressed, fatigued horse will develop gut stress.

Thankfully, nature has provided us with a wonderful range of herbal therapeutics with their actions which can really help. First up, we alleviate those symptoms - we likely have nasal catarrh, so we need an anticatarrhal; for the itching, we'll use an antipruritic, and if you've got itching you've got inflammation - enter an anti-inflammatory with cooling astringent properties to tighten everything back up again. A bit of antihistamine help wouldn't go amiss either, and finally, for the stress levels, we add in a gentle nervine.

Now to the root source of the problem, the overproduction of histamine creating its own allergy response, causing a runaway immune system that needs 'normalising', so we need adaptogen support by way of an immunoregulator, alongside anti-allergenic action.

For the all-important lymphatic system, the lymph nodes with the liver and kidneys - or what I call the 3-Amigos - make up the body's natural detox filtration system, which may need a reset.

Vitamin E and Selenium are also powerful antioxidants which have a positive effect on the upper respiratory tract and lung tissue, both of which are included as standard in our EquiVita range of balanced mineral solutions.

Allergic responses don't have to make life miserable for you and your horse. Keep the gut function, the microbiome and the immune system healthy and you're not just fighting the battle - you're already winning the war.