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Barn Air Quality: Coping with extreme cold


“My friend told me that it’s better to keep the windows open in the barn so fresh air circulates, even in the winter. Is that still true in the middle of a polar vortex? I hate to leave the barn open when the windchill is -40!” – Submitted via

I hear you, friend. You and I must live in the same part of the country because my horse and I saw that same crazy wind chill number a few weeks ago (for those of you who don’t live in parts of the country that experience cold, “wind chill” or “wind chill index” is defined as the perceived decrease in air temperature felt by the body on exposed skin due to the flow of air). Contrast this to the heat index which combines air temperature and relative humidity to determine the human-perceived equivalent temperature—how hot it feels (both definitions courtesy of Wikipedia).

Personally I’m at a small, seven-stall barn that is not heated, insulated, or air tight (plus the stalls are kept immaculate) so the environment never really gets stale. But we did close all the doors and windows for a day or two when it got really cold instead of leaving them open at least a crack. And while being next to a middle school may have its downsides, an upside is that we can use the direction their flag is waving to decide which door and windows to leave open. In the winter, we try to leave the side of the barn open that the wind will not directly blow into, while in the summer we do the opposite, to catch a cooling breeze. I have to brag that we do a lot of other things right, such as feed high-quality hay and store it in a completely different barn, clean stalls and sweep aisles only after the horses have been turned out, and most of all, turn out as much as possible (we’re pretty much on a dawn-to-dusk schedule, so 7am to 5pm in the winter and 7am to 9pm in the summer). Our horses have pretty healthy airways!

Besides the human comfort factor, why do we care about clean smelling, fresh air circulating in the horse barn? My go-to website for all things equine respiratory is the Tufts University Cummings School of Veterinary Medicine, since they have a world-renowned laboratory filled with world-renowned researchers. You can learn all about equine asthma or “heaves”–called Chronic Obstructive Pulmonary Disease (COPD) or, more correctly, Recurrent Airway Obstruction (RAO)—and its precursor SAID, which stands for Small Airway Inflammatory Disease and is a disease of the lower airways causing cough and exercise intolerance. Here’s what the Suspected Causes page says:

  • Horses lives, eat, and work in a dust-laden environment
  • Some horses work in urban areas, which are polluted
  • Dust and air pollutants contribute to SAID
  • Dust is composed of various molds, bacteria, and their toxins, minerals, insect parts, and various chemicals—all stuff that can’t been seen with the naked eye
  • Air pollutants are mostly gases, like ozone, sulfur dioxide, and nitrous oxide, but particular matter, such as heavy metals, carbons, and smoke, contribute to pollution exposure in urban horses.
  • Air within the stable can be polluted with ammonia, bacterial byproducts (e.g. endotoxin), molds, and other chemicals which irritate the airways.

The website goes on to describe How Allergens Cause SAID:

  • The horse’s lung is huge—it samples thousands of gallons of air in just a few minutes of intense exercise.
  • Dust particles enter airways and are trapped on their inner surface.
  • Dust, gases, and chemicals severely irritate the sensitive airway lining.
  • The airways, which are active living tissue, mount a rapid and aggressive defense called inflammation.
  • The extent of this reaction appears to depend on the susceptibility of the horse.
  • Some horses mount a stronger, more prolonged defense reaction, which can cause more harm than good.
  • It has been speculated that viral infections can precipitate SAID.
  • Airway inflammation results. Mucus and cellular debris accumulate within the airways, the airway walls thicken, constrict, or collapse.

I’ll let you read for yourself the signs, terminology, pathophysiology, diagnosis, and treatments of Small Airway Disease/Heaves at

But your friend is right: allow the air to circulate in your barn even when it’s cold for healthier horses!

Lydia F. Gray, DVM, MA SmartPak Staff Veterinarian and Medical Director Dr. Lydia Gray has earned a Bachelor of Science in agriculture, a Doctor of Veterinary Medicine (DVM), and a Master of Arts focusing on interpersonal and organizational communication. After “retiring” from private practice, she put her experience and education to work as the American Association of Equine Practitioner’s first-ever Director of Owner Education. Dr. Gray continues to provide health and nutrition information to horse owners through her position at SmartPak, through publication in more than a dozen general and trade publications, and through presentations around the country. She is the very proud owner of a Trakehner named Newman that she actively competes with in dressage and combined driving. In addition to memberships in the USDF and USEF, Dr. Gray is also a member of the Illinois Dressage and Combined Training Association (IDCTA). She is a USDF “L” Program Graduate and is currently working on her Bronze Medal. Find Dr. Gray on Google+

Posted in Ask the Vet, Barn Skills

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4 comments on “Barn Air Quality: Coping with extreme cold
  1. Sally Lombardi says:

    I’m curious though. Wild horses deal with many environmental factors that cannot be controlled: stand in wet mud/grass for long periods, run til sweaty but don’t get washed down/dried/walked til cool, run and live in very dusty areas during summer drought. Do they too develop the same respiratory, hoof rot, arthritis and other conditions as their domesticated cousins? And should barns not be heated (are they healthier if they are not)? Thanks- I cannot get enough info…

    • SmartPak SmartPak says:

      Hi Sally, it’s great that you’re thinking critically about these horse management situations! The simple answer to your question is that yes, both wild and domestic horses will be impacted by environmental factors such as extreme cold, dust, overly wet or overly dry situations. Although we are often trying to mimic a natural environment for our domestic horses, this is not to say that wild horses are immune to certain conditions just because they’ve never been in a stall or carried a rider. Wild horses, just like our domestic ones, can still be prone to health issues with their feet, joints, respiratory system, etc. One good example of this is research done on the joint health of wild mustangs. Even though these horses had never been ridden, they showed evidence of various stages of osteoarthritis. Put simply, both wild and domestic horses can develop similar health conditions. – Dr. Lydia Gray

    • Vasyl says:

      It was a co-ordinated act of defiance in salidority with horsemen who were marching to protest a lack on movement on long promised VLTs. It had nothing to do with trainers alarm clocks or moring training.

  2. aallegre says:

    Hey there! It appears the heaves link is linking to a ‘Page not Found’ page on the Tufts website.

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