Horses with asthma

Are there certain times of year when it’s worse? What are your horse’s triggers? My girl has been fine for almost a year, but just started up again.

My gelding has equine asthma. We’ve owned him since he was a yearling and he has spent most of his life living out 24/7 with access to roundbales because he cribs. Most people think he’s super mellow, but he internalizes a lot of stress.

During the fall of 2020 he started have asthma attacks, resting respiratory rates up to 40 breaths/min, coughing at rest, etc. I could hear phlegm in his trachea. Dex was required to get episodes under control. Once the snow came in early November he was fine, so we suspected environmental irritants.
Prior to that he had never really coughed, but would occasionally produce a glob of nasal discharge. We also had several years of really stubborn scratches and rain rot that required rounds of sulfa to control.

Spring of 2021 I took him for intradermal allergy testing. Very allergic to staph bacteria and a couple different molds, spiny pigweed, yeast, cats, dust mites, wool, house fly, and golden rod.
Mild reaction to birch, poplar, alfalfa.
Most of these things I have little control over, and some years they’ll be worse, some better.

He’s been doing the immunotherapy since June of 2021. Spring of 2022 was difficult. It was wet for awhile and I suspect there was a lot of mold in the mud and melting snow. It took about six weeks of dex and several attempts to wean him off before he was back to normal. He was fine through the fall of 2022, we’ll see what spring brings. They say that in can take a couple years before the shots really work.
On the plus side, he hasn’t developed any skin issues since being on the shots.


Yes, it seems to coincide with the onset and peaks of pollen levels. The three primary times are due to grass, trees, and ragweed. there are 3 separate peaks during each year. Check your area’s data to see when these typically happen in your location.

I had one horse with many positive allergen tests, and I charted and followed this data for years. I finally arrived at a point that I was able to anticipate and adjust his dexamethasone dose amounts and timing to pretty much keep him comfortable all year. But tree, grass, and ragweed times were when I had to really increase his doses and frequency.

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That’s interesting that you tried the shots. Our vet was out today and mentioned that treatment. She did draw blood and it’s possible that our mare has an infection, whether primary or secondary is unknown. When she started coughing, I reached for the dex, because that’s what we treated her with last time, but I had second thoughts because it had been so long since she had an episode. I’m glad the vet came out and started her on antibiotics. She responded to Zyrtec (generic) in the past. I just need to remember to start her on that before she starts coughing.

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Does your horse respond to antihistamines at all? I feel fortunate that our mare seems to respond, as long as I start her before she gets bad.

I’m in Canada and this horse is 13 and competes. In Canada we aren’t allowed to show while on dex or any of the other respiratory drugs. This is the main reason that I opted to try immunotherapy.

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Mine is most affected in the summer, but sometimes he’ll flare up in reaction to a “bad” bale of hay. I have the stethoscope on him almost every day, and count his breath rate.

Drug management includes daily Prednisolone and Hydroxyzine in season, and Ventipulmin for flare ups. He also gets Omega Alpha’s RespiFree daily, year round. The season starts earlier and goes longer every year. Other; management includes living out, netted hay, and exercise. He’s on the injured list this winter, which is making it harder when the flare ups happen.

I treat flare ups aggressively as a vet once
advised me to not wait and see with lung issues. Once the lung tissue scars, that function is lost permanently. Another vet advised me to contact them sooner than later if the drugs were not effective. I have also seen fellow boarders reach the limit of what pharmaceuticals could do for their horse…

In 2022 I experimented with a Bemer equine set and was quite pleased with the results (test group of 1).

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I know how my horse responds to his medications, and once caught pneumonia before it really got started because I was able to call the vet and say “he’s not responding to the meds the way he usually does.”


No, little to no effectiveness to antihistamines. And his attacks were severe so we jumped right to big corticosteroid doses. I had training and experience and had done research and was on the medical lecture circuit in clinical pharmacology of corticosteroids at that time, so the vet was OK with me doing the daily dosing decisions, and he kept me supplied with dexamethasone. Vet and I also hunted together so he got regular updates from me.

A visiting vet student at his office called me aside one day as I was there picking up dexamethasone and proceeded to lecture me, not in the presence of the vet, on the dangers of steroids. I just listened calmly and thanked him for the information.:zipper_mouth_face: The urge to lecture him back was awfully hard to control, though.


That makes perfect sense.

Oh wow. That took some self control, lol. I’m glad dex is available. Our vet suggested using a form of prednisone, if my mare needs it long term. I’m not sure why, but I think there would be less symptoms at her dosage. All horses are different, though.

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It sounds like you’ve really got a good handle on the treatment. Well done.

We just moved to an entirely different climate and this is the first flare up in nine months. Probably triggered by the hay I was feeding (we switched).

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My horse has mast cell rich mild equine asthma. Worse in summer for me, but it is low humidity here year round, and that doesn’t help. He does much better in a humid environment. Biggest triggers are particulates in the air (moderate to high AQI), so pollution, smoke, dust, etc. Not so much a correlation to any weed, plant, or pollen that I’ve noticed.

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That’s interesting. It’s good to know the triggers, either through the process of elimination, or testing.

Just got the results back and my poor mare does have an infection. Not sure which came first, the cough or the infection, but both are being treated now.

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I’ve been looking after his breathing for eight years now. My vet also trusted me to manage drug doses, with discussion around any major changes and reminders of maximum safe doses. I know what he sounds like, what his breathing looks like, what his normal breath rate is and how he responds to drugs and exercise under various conditions. I absolutely rely on my stethoscope.

Unfortunately I have new vets and I’m hoping they’ll trust me without my having to allow my horse to flare up badly and do an emergency call. :worried: His dam died from her heaves, and barring some catastrophe I expect that his breathing issues will bring his end.

The way things have progressed (more medication and careful management every year) I thought 2023 could very well be his last summer (the heat and humidity make him worse). After last summer with the Bemer I’m optimistically hoping for another 3-5 years.

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Good for you in catching it early! I hope she’s feeling better soon!

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Please educate me on how the Bemer helps.

I too have a mild heaves (progressing) horse with a tendency to get infections that complicate everything. Last summer was awful.

I was worried when we moved, but, the new vet had some better ideas and a lower dose actually worked on her cough. It was a good to get a second opinion. I hope you have a similar experience.

I post the same thing to everyone. Have you had your horse allergy tested? If you don’t know what they are allergic to, you can’t make environmental or diet management decisions to improve their symptoms.

My horse was retired/unrideable last spring because I was feeding her hay with grasses she was allergic to and she was having symptoms even with steroids and antihistamines etc. flexineb made everything 10x worse. I switched her to timothy hay (one of the 2 grasses she was not allergic to) and her symptoms improved 99%. She stopped coughing and got off steroids completely. She is now rideable and mostly symptom free.

I will note that the allergy shots did not work for my horse, but using the results to make feed decisions did majorly. If you are feeding your horse something they are allergic to (even if you are steaming the hay etc) they will still have symptoms unless it is specifically the mold/dust they are allergic and not the grass species itself. Good luck!

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