The respiratory tract is an organ that is commonly impacted in the horse, resulting in COPD and IAD. Inhalation of oxygen is vital for energy production and overall cellular health, but in many equine athletes, they struggle to move air in and out resulting in decreased performance and quality of life. Many horse owners rely heavily on pharmaceutical medications such as steroids and bronchodilators, but despite their use, their horse continues to struggle to gain results and improve in quality of life.
Respiratory conditions are very common in the horse, including upper respiratory infections, allergies, inflammatory airway disease (IAD) and chronic obstructive pulmonary disease (COPD). When we are confronted with these patients, as veterinarians, the conditions are often progressed and moderate damage has occurred within the airways. This can limit the capabilities of our therapies. In many cases, these therapies are not really managing the disease itself, but more so the clinical signs.
Almost every breed is susceptible to the conditions of COPD, IAD, and respiratory allergies, but more so the Quarter Horse, Thoroughbred, and Warmblood are more highly represented. After working with these patients over many years, I think we need to dig deeper into their conditions, connecting the dots and seeing how the problem is manifesting in each horse as an individual. This can then help us to further the success of therapy.
Physiology of Respiratory Conditions in the Horse
You have to understand that each of the above mentioned conditions, ranging from infections to COPD and IAD, are all really separate entities but despite being separate, they are connected. In each of the conditions, there is an overly expressed inflammatory response, often spear-headed by a dysfunctional immune system. The immune response is primarily responsible for inflammatory protein production, which results in numerous changes to cellular function and tissue health.
In the case of a respiratory infection, the immune system is simply doing it’s job, reacting to an invading bacteria or virus, contributing to a cough and even mucous or phlegm production, all in an effort to eliminate the invader from the body. In these cases, it is also common to have a rise in the body temperature, in the form of a fever, to further help eliminate the pathogen. Most cases in the hors resolve uneventfully, often with the assistance of antibiotics and possibly medications to control the fever.
The remaining three conditions in horses (allergies, IAD, and COPD) are very similar from my point of view. Actually, many cases of IAD and COPD have an underlying allergic component which has just simply progressed or advanced over time.
Allergies in the horse are a somewhat complex situation, where the immune response essentially fails to respond appropriately to allergens. Essentially, the immune response cannot differentiate from a potentially lethal invader and a benign or non-harmful one. No matter if the invader is dust, pollen or a bacteria, the immune response acts as if WWIII is about to occur, responding in a heightened manner with inflammatory proteins which then signal cellular changes. The body begins to cough, produce mucous and phlegm. In some cases, the airways begin to close up or narrow, which is compounded by mucous accumulation within those airways. Over time, the inflammatory response contributes to scar tissue and loss of normal cellular function. In the case of skin allergies in the horse, the inflammatory proteins produced result in redness and itching, often also with a moist drainage to lesions.
In cases of IAD, we have a strong inflammatory response, which results in inflammation within the airways. In some cases, this elicits a strong cough, but in others, the airways also tend to narrrow which can further contribute to the cough, oxygen flow and thus, performance.
COPD is somewhat similar to IAD, but this condition is more progressed over time. Some may argue that equine IAD patients are actually more prone to developing COPD over time. Here we often see coughs, mucous production, phlegm, and narrowed airways but many of these patients also have a very difficult time moving air either in or out, due to degenerative changes present in the lungs.
Diagnostics Used to Evaluate Equine Respiratory Patients
The diagnosis and determination of each of the above equine respiratory conditions often involves the same clinical testing, but in many advanced cases, our final diagnosis is purely speculative based on the findings.
In all of these horses, we start with a basic physical exam including a full history, temperature, heart rate, and respiratory rate. It is important to fully evaluate the lungs and breathing, detecting audible noises which may clue us in on narrowed airways and mucous accumulation. Bloodwork is also vital to these cases, as it helps us to determine the presence of secondary infections which are not uncommon due to the mucous accumulation, narrowed airways, and reduced ability to fully ventilate the lungs.
In the more advanced cases, especially IAD and COPD, further diagnostics including endoscopic exams, transtracheal washes, bronchoalveolar lavages, and even lung ultrasounds may provide us with more information. In many cases of allergies, including COPD and IAD, it is not uncommon to find specific types of white blood cells such as mast cells or eosinophils, which are contributing to the response. We may also find organisms, including bacterial and fungal, which may either be primary invaders or secondary in nature.
Traditional Treatment Options for COPD and IAD in the Horse
In the case of mild respiratory infections, traditionally these patients often do well on their own if their immune response is normal and strong. Antibiotics and possible non-steroidal medications may be employed to help the horse along in their recovery.
In cases of allergies, IAD and COPD, the treatment options become slightly more complicated which is dependent on the status and progression of the patient. One thing to keep in mind is that with advanced changes in the lungs, the patient is more susceptible to secondary bacterial infections, so it is not uncommon to use antibiotics even in cases of allergies, IAD and COPD intermittently.
Allergy testing may be employed in some allergy patients, often chosen as an end-result due to the patient not responding as desired to medications, which can be done via blood sampling or intradermal antigen testing. The results of these tests can be interesting as often the patients are demonstrating an allergic response to almost everything from cereal grains to hay types. Based on the results of the allergy tests, often either the diets and/or environment are altered to reduce exposure to those allergens or the patient is hyperimmunized, or essentially vaccinated against the allergen. These allergy injections are then given for prolonged periods of time with the sole goal of telling the immune system this particular allergen is ‘okay’ and not to react to it. It is in my point of view that these allergy tests need to be further evaluated. I think we need to carefully interpret the results, as we need to remember that in these cases of allergies, the immune system is hyper-responsive, overly reacting to almost everything and anything. Does that necessarily imply that the patient is truly allergic to those things? Personally, I don’t believe that to be true as explained later in this article.
In more advanced cases of allergies, IAD and COPD, the treatment options are actually very similar. In these cases, veterinarians often rely on variable doses of corticosteroids to lower the inflammatory response and essentially shut the immune system down. It is also not uncommon to use bronchodilators in various forms to help open airways and allow the horse to breathe easier. These medications are not without their side effects and risks, especially as the dose and frequency increase over time. Side effects include secondary infections, liver disease, iatrogenic Cushing’s disease, laminitis, kidney disease, and even abnormal heart rhythms and excitability. Despite these treatment options, many patients continue to progress over time, becoming worse and more and more dependent on these medications. In many cases, the medications often fail to exert benefits to the patient, which is likely due to severe degenerative changes which have occurred.
A New Therapy Approach to COPD and IAD in the Horse
The incidence of allergies, IAD and COPD in the horse is continuing to increase with each year. In many of these cases, the patients often progress or become worse from year to year, requiring further veterinary care, diagnostics and medications…all at a significant cost. We have to also keep in mind that as the condition progresses, performance is likewise negatively impacted which can limit their overall success.
The bottom line connector with all of the above conditions is inflammation and a poorly responsive immune system, being tied closely together. In the cases of respiratory infections, we want the immune system to respond properly and create an inflammatory response which hopefully will aid the patient’s recovery. However, in the case of allergies, IAD and COPD, we want a more balanced and healthy response.
The immune system is directly tied in with the gut or GI tract, as this is often seen as ‘home base’. What happens in the bowel is often reflected in the entire body. Without getting too complex, there are a variety of problems which may be occuring at a gut level from bacterial infections to diet and inflammation, which may actually be contributing to a heightened or improperly functioning immune system. This was discussed in our “Leaky Gut” article.
Based on the discussion in that article, we have several things to consider and/or explore in these patients. These include changes in bacterial populations within the gut, which may contribute to inflammation and immune response. These changes in bacterial populations have been known to occur, not only in cases of Salmonella and Clostridial infections, but also secondary to dietary issues and possibly genetic influences. In metabolic equine patients, it has been known in research that these bacterial shifts may actually contribute to susceptibility to pasture associated laminitis and leaky gut syndrome.
It is also interesting to note that in many cases of IAD, especially in those horses on the race track, there is a strong connection with a history of recurrent respiratory infections and also environmental influences which may be laying the foundation for the condition to occur. Many cases of COPD, as an example, also have a strong history of allergies, which again, may lay the groundwork for progressive deterioration over time if uncontrolled.
So, the main goal with all of these conditions is promote a balanced immune and inflammatory response. If we can do this successfully, then hopefully the patient will respond favorably and long term management proven a lot easier. One may say that they are using medications and other supplements to achieve this, but if you are still having problems, then we can do better. We have to look at the presence of any of these problems as an indicator of poor health…so essentially, we are trying to restore health on many levels. The level of response by the patient, however, is often dictated by the severity of the condition, how much damage has been done and therefore the amount of time that has passed. Prevention is always the key to health and in many of these patients, we often fail to see the initial clinical symptoms such as a persistent slight cough when worked or a more difficult time in breathing. Sadly, these are the most ideal time to intervene, not so much with medications but more so targeted supplemental therapies, but all too often they are overlooked. Once damage is done at a cellular level, there are few things, including medications that can reverse it.
Alternative Management Approaches to COPD and IAD in the Horse
My first-line approach is to gather information, including bloodwork and physical exam findings. We need to know everything about this patient, including when and how the problem presents. Is there a cough and if so, is it productive, meaning is it moist with mucous or phlegm production or is it a dry, hacking type of cough. Most equine COPD patients have productive coughs with mucous/phlegm production, while IAD patients are often more dry in nature. With that being said, often allergies are at the root or a precursor to these conditions and can also be either productive or non-productive in their presentation. This is actually one of the key determinants which guides my chosen course of therapy.
Keeping in mind that we have both an uncontrolled inflammatory and immune response, these are our targets in therapy. The other thing, which is interesting to note, is that a high percentage of COPD and allergy horses with productive coughs are also easy keepers, meaning they are prone to being overweight. This is interesting to note, because traditionally, overweight animals and people tend to have a higher prevalence of underlying GI problems, which takes us back to the whole leaky gut/immune situation mentioned above.
In our easy keeper, productive type of coughs with allergies and COPD, I tend to use our Cur-OST® EQ Total Support to help balance the inflammatory response, provide cellular antioxidant support and target the GI tract and reduce mucous production, specifically with Dandelion, Marshmallow, and Parsley. This formula helps to balance the inflammatory response on a systemic level but also target the gut, which is often the main underlying problem area. In conjunction with the EQ Total Support, I will also take advantage of the Cur-OST EQ Immune Full Spectrum formula, which allows me another route to control or balance the immune response. The two formulas are given together, usually for 60-90 days total, but then we can hopefully rely on daily use of the EQ Total Support for the long term. Many patients respond very well in a short period of time and can be dropped back to the EQ Total, but again due to condition progression, many still benefit from long term use of the combination approach.
In our non-easy keeper and IAD cases, we still have an underlying GI problem but it does not generally require the same approach. Here, we have an overly active inflammatory and immune response, but the production of phlegm and mucous is not significant. In these patients, my initial approach is through the use of our Cur-OST® EQ Plus which helps us to balance and promote a more normal inflammation response. In addition, we may also utilize the Cur-OST EQ Immune Full Spectrum, again to help promote a balanced immune response. The formulas are utilized together, often for 60-90 days, and then we will rely on the EQ Plus for the long term, unless the patient dictates otherwise. It is to be noted that in many of these cases, the cough and airways are often ‘dry’ in nature, due to long standing inflammation. This dryness contributes to the cough through airway irritation. In many instances, I have found significant benefit through the additional use of our Cur-OST® EQ Stomach formula, which soothes these airways through the use of high levels of Aloe and Marshmallow. It is interesting to note that many of these patients also suffer from gastric ulcers and anxiety, which may likewise respond favorably.
Diet, I believe, is a major contributor to these problems as often, the diet dictates overall health of the GI tract. I often promote a more ‘clean’ or healthy diet for these patients, utilizing whole cereal grains and high quality hays, steering clear as much as possible from high use of synthetic-based supplements, hay balancers and commercial feeds. The reason for this is that I feel, based on our research data, that the higher use of these forms of ‘foods’ and supplements, the more prominent the underlying GI problems. When I recommend moving towards a clean diet, this is not so much because of what those grains can do, but more so it is about what we are not feeding, in regards to preservatives, additives, sweeteners and artificial nutrients. Essentially, we are making a move towards more natural foods, which provide nutrients in their natural form. If we make the migration to a more healthy diet, the patients just do much better in my experience, which is due to us potentially removing contributors to the inflammatory and immune situation.
Now, the bottom line question for most horse owners is whether they can reduce or eliminate medications and will their horses perform and feel better? The answer to this, on multiple levels, is YES, but needs to be done under veterinary guidance. Often, subtle changes to diet and supplement regimens can result in significant improvements in a short period of time. Many others continue to show more and more positive changes as weeks and months go by, with notable improvement not only in in clinical signs, but also in body condition, feed efficiency, performance and overall health. It is not uncommon to also note positive improvements in hoof growth and even some lameness conditions, as all inflammation is often interconnected. Not all patients respond as favorably as others, which is usually due to progressive degenerative changes which have occurred, including scar tissue and permanent lung damage.
We can always do better for some of these patients, and this is something we continue to explore at Nouvelle Research. The cellular pathways involved are quite complex and far reaching, but the above approaches give us a good starting point which tends to benefit upwards of 80% of the patients.
I hope this information is helpful.
Tom Schell, D.V.M.
Nouvelle Research, Inc.