How Stress Affects the Horse’s Gut and Immune System

If you work with performance horses, you know the high demands placed on these animals. The pressures of rigorous training, regular hauling, and staying performance-ready can be intense and have physical repercussions.

Do you know how to tell if your horse suffers from chronic stress? You need to know the sources, signs, and effects of stress—especially how it impacts the equine gut and immune system. Knowing what to look for and what you can do enables you to put your horses on course to a healthier lifestyle. Horses better able to handle and recover from stress can have healthy, successful, and long careers.

Recognizing Stress in Horses

Innately prey animals, horses are naturally skittish, and many environmental factors contribute to the stress they experience. Anything outside the norm of quietly wandering and constantly grazing within a herd can trigger a flight response. A horse consistently exposed to perceived “threats” may develop chronic stress, the root of many health issues.

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Sources of Stress in Horses

Some of the most common sources of stress for performance horses include:

You can see how if your horse is anything but a pasture pet or retired on pasture, it’s at risk of being chronically stressed.

Signs of Stress in Sources

Just like with humans, the way one of your animals exhibits stress may be different than the way another does. However, there are a handful of typical stress signals you can look for in your horses. What are some potential signs of stress in horses?

While these can signal a stressed horse, they are also common signs of various internal conditions. These symptoms may arise from stress or from some other kind of other digestive problem or pathology. It is always important to consult with your veterinarian when you have concerns about your horse.

How Stress Negatively Impacts the Body

It’s incredible how stress can impact every system in the body. Stress initiates an adrenaline response, which floods the body with hormones. The release of cortisol, the primary stress hormone, does several things:

• increases sugars (glucose) in the bloodstream
• enhances the brain’s use of glucose
• increases the availability of substances that repair tissues
• curbs body functions that would be nonessential or harmful in a fight-or-flight situation

Cortisol diverts energy from the immune system and redirects it to the heart, lungs, and muscles. Outwardly, this appears as a physical burst of energy. In a flight or fight situation, the adrenaline rush allows the horse to escape danger/discomfort and deal with the inflammation within its body later.

Effects on the Immune System and the Gut

You would expect a fight or flight response when danger is near. However, constantly living in stress mode prevents the horse from recovering and resetting the body back to normal. When this stress response happens regularly, it negatively affects the immune system and gut of the horse.

Prolonged high cortisol levels caused by continuous stress, chronic pain, or a metabolic condition can lead to protein catabolism. This increases gut permeability and reduces mucus production, making way for bacteria to enter the bloodstream. Further, chronically high cortisol decreases the horse’s ability to heal wounds and increases muscular atrophy – a disastrous combination for horse training and performance horses.

Chronic immune insufficiency can lead to a heightened risk for infections. On top of that, dysregulation of the immune system can cause hyper immunity and immunosuppression. Stress can also overload an animal so much that the system simultaneously upregulates and downregulates. This paves the way for constant health risks.

The Link Between the Gut and the Immune System

Chronic stress can ultimately affect the immune system, further degrading gut integrity. The gut lining is thin to allow the absorption of nutrients. But this is also its downfall. Since the easiest way for a pathogen is through the gut lining, 80 percent of the immune system is devoted to the GI tract.

Most of a horse’s immune cells are in the lymphatic system, concentrated in the gut. This complex network of lymph nodes stretches into the coating of the intestines creating an intimate connection between the immune and digestive systems.

How to Combat the Effects of Stress on Gut Health

The gut-brain relationship is a two-way street. When under stress, the brain can modify gut microbiota. On the other hand, gut microbiota can impose moods, such as depression or anxiety, on the brain. Be proactive in your animal’s care to ensure your horse maintains good gut health.

One of the best ways to manage your performance horse and encourage peak performance is to cut down on the stress where you can and support the health of microbiota through supplementation.

Decrease Stress Where Possible

Since we’ve already determined many of the causes of stress for your performance horse, consider which things you can cut back on or do differently to help your horse stay more regulated in their stress levels.

Provide ample forage for your horse, keeping grass or hay in front of them as close to 24/7 as possible. Be conscious of how frequently and to what extent you trailer your horse. Be flexible in your training schedule and let their actions—physically and medically—dictate whether they are being overtrained.

While you may be able to reduce the stressors in your horse’s life, you likely can’t get rid of all of them. That’s where a good digestive supplement steps in to support your horse’s health in facing these challenges.

The Benefits of Supplements to Support Digestive Health

One of the best ways to support your horses and their gut health is to provide a scientifically based, proven digestive supplement daily. The jury is still out on probiotics (live bacteria), while prebiotics that feed the growth of beneficial bacteria in the hindgut have been shown to be very useful.

In addition, certain natural substances work to maintain the healthy structure and function of the entire digestive tract. These include:

• Yeast: keeps the hindgut balanced, feeds beneficial bacteria in the gut, and supports a healthy gut lining.
• Beta glucan: supports immune health, maintains a healthy rate of digestion, and reduces LDL cholesterol.
• Polar lipids: assist nutrient absorption, the strength and integrity of the mucosal barrier, and normal brain function.
• Amino acids: contribute to a smoothly functioning GI tract and assist metabolism, mucus production, cell repair, and more.

Utilizing supplements that help your horse replenish these vital nutrients is key to maintaining a healthy, happy horse.

Anything you can do as a horse owner to diminish stress and maximize the health of the gut and the immune system is crucial to the care of your performance horse.