The Impact of Air Quality and Pollution on Your Horse’s Lungs
The Impact of Air Quality and Pollution on Your Horse’s Lungs
Theres nothing like hearing a horse cough to set people scurrying around the barn to identify the culprit. After all that cough could mean choke or suggest that a respiratory virus has found its way into the barn. It could also indicate equine asthma. Yes even those everyday coughs that we sometimes dismiss as summer cough or hay cough are a wakeup call to the potential for severe equine asthma.
Formerly known as heaves broken wind emphysema chronic obstructive pulmonary disease COPD or recurrent airway obstruction RAO this respiratory condition is now called severe equine asthma sEA. These names reflect how our scientific and medical understanding of this debilitating disease has changed over the years. We now consider heaves to be most comparable to severe asthma in people
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But what if your horse only coughs during or after exercise? This type of cough can mean that the horse has upper airway irritation throat and windpipe or lower airway inflammation lungs meaning inflammatory airway disease IAD which is now known as mildtomoderate equine asthma mEA. This airway disease is similar to childhood asthma including that it can go away on its own. The disease causes reduced athletic performance and a proper diagnosis by a veterinarian is important because there are different subtypes of mEA which benefit from specific medical therapies. In some cases mEA progresses to sEA.
The Relationship Between Equine Asthma and Air Quality
Equine asthma has a lot to do with air quality. Poor air quality or air pollution includes barn dusts the allergens and molds in hay and the bacteria in tiny particles of manure as well as arena dusts and ammonia from urine. Also gas and dieselpowered equipment contribute to air pollution for both people and horses resulting from equipment being driven through the barn a truck left idling by a stall window or the smog from even a small city drifting nearly invisibly over the surrounding farmland. Forest fire smoke is another serious contributor to air pollution.
Smog causes the lung inflammation associated with mEA. Therefore it is also likely that air pollution from engines and forest fires will trigger asthma attacks in horses with sEA. Smog and smoke contain many harmful particulates and gasses but very importantly they also contain fine particulate matter known as PM2 5 referring to the diameter of the particle being 2 5 microns. That level is roughly 30 times smaller than theslideshow”
The Impact of Air Quality and Pollution on Your Horse’s Lungs
of a human hair. Because it is so small this fine particulate is inhaled deeply into the lungs where it crosses over into the blood stream. So not only does PM2 5 cause lung disease it also causes inflammation elsewhere in the body including the heart. Worldwide even shortterm exposure is associated with an increased risk of premature death from heart disease stroke and lung cancer.
Symptoms Diagnostic Tests and Treatments
Equine asthma manifests with a spectrum of symptoms that vary in severity and degree of debilitation they cause. Just like in people with asthma the airways of horses with mEA and sEA are hyperreactive. This means that the asthmatic horses airways are extra sensitive to barn dusts that another horses lungs would just ignore. The asthmatic horses airways constrict become narrower in response to these dusts. This narrowing means its harder to get air in and out of the lungs. Think about drinking through a straw. You can drink faster with a wider straw than with a skinnier one. Its the same with air and the airways. In horses with mEA the narrowing is mild. In horses with sEA the constriction is extreme and is the reason they develop a heave line a visible line of abdominal muscles that develop as the horse tries to breathe and push air out of their narrow airways. They also develop flaring of their nostrils at rest to make their upper airway wider to get more air in. Horses with mEA do not develop a heave line but the airway narrowing and inflammation do cause reduced athletic ability..
Another very obvious feature of horses with sEA is their persistent hacking cough which worsens in dusty conditions such as when fed dusty hay or working in a dusty arena or on a dusty track. The cough develops because of airway hyperreactivity and because of inflammation and excess mucus in the airways. Mucus is the normal response of the lung to the presence of inhaled tiny particles or other irritants. Mucus traps these noxious substances so they can be coughed out which protects the lung. But if an asthmaprone horse is constantly exposed to a dusty environment it leads to chronic inflammation and mucus accumulation and the development or worsening of asthma along with that characteristic cough.
How Veterinarians Accurately Diagnose Equine Asthma
Veterinarians use a combination of the information you tell them their observation of the horse
Theres nothing like hearing a horse cough to set people scurrying around the barn to identify the culprit. After all that cough could mean choke or suggest that a respiratory virus has found its way into the barn. It could also indicate equine asthma. Yes even those everyday coughs that we sometimes dismiss as summer cough or hay cough are a wakeup call to the potential for severe equine asthma.
Formerly known as heaves broken wind emphysema chronic obstructive pulmonary disease COPD or recurrent airway obstruction RAO this respiratory condition is now called severe equine asthma sEA. These names reflect how our scientific and medical understanding of this debilitating disease has changed over the years. We now consider heaves to be most comparable to severe asthma in people.
