We live in a hostile world to many visible and invisible bugs, viruses, bacteria and other small organisms. This is especially true for our equine companions. Thus, an important aspect of equine care is ensuring your animal stays healthy by boosting their immune system.

For optimal horse health, a robust immune system is required. This bodily system is made up of cells, proteins and tissues, all set up to defend a horse’s body from any invader, like a virus, from infection. When a virus, bacteria, parasite, or other microorganism enters the body, the immune system kicks in. It recognizes these cells as “foreign” and mounts an aggressive attack until all the invading material is killed or neutralized.

A horse’s first line of defense against many diseases and parasites is through a sound vaccination and deworming plan. Another very important consideration is a horse’s diet. Generally, if a horse is already receiving adequate nutritional support, their immune systems should be functioning at an acceptable level. However, if a horse is ever stressed, they may need additional nutrients to keep them healthy.

A horse’s immune system is usually not stressed when undergoing light to even moderate levels of activity. Even a short-term stressor usually does not negatively impact a horse’s immune system. Yet, more chronic types of stressors may compromise a horse’s immune system, leaving them susceptible to illness. These stressors can include:

  • Moderately high to high levels of exercise
  • Frequent travel or travel over long distances
  • Injury recovery
  • Frequent changes in the weather
  • Poor diet or undernourishment  
  • Any other chronic stressor

Age also factors into the immune system. Every horse ever born is born without immunity to our hostile world. Through the mare’s colostrum, or first milk, the foal receives the immunity it needs until it develops its own immune system. After this time (~ 2 to 3 months of age), their immune system is functioning adequately. For aged horses (late teens and onwards), their immune systems do not work as efficiently or quickly. Thus, all these types of horses can stand to benefit from additional nutritional support through their diet to provide an added immunity boost.

There are many specific nutrients that contribute to a healthy immune system:

Protein: High quality protein is always important to a horse’s diet. The amino acids provided by protein are also critical to a healthy immune system. These act to help form important components of immune cells, enzymes, and other material used to maintain optimal health.

Fatty Acids: The omega-3 and omega-6 fatty acids play key roles in a horse’s immune system. The omega-3 fatty acids help by reducing inflammation in the horse. Whereas omega-6 fatty acids support the inflammatory response of the immune system to fight disease.

Vitamin E, Vitamin C, and Selenium: These act as “antioxidants.” Antioxidants help reduce or prevent damage to cells and tissues during times of stress or illness. We have detailed the role of antioxidants in a horse’s body HERE.

Vitamin A: Another important vitamin that helps enhance the function of many immune cells is vitamin A. Grazing horses generally receive generous amounts of beta carotene, which is converted to vitamin A in the horse’s digestive system. In turn, vitamin A not only enhances immune cells receptivity, but also works to enhance the antioxidant vitamins C and E.

Zinc: Zinc is recognized as a key nutrient for a healthy immune system. While studies have not been specifically conducted in horses, in humans, zinc has shown to have anti-inflammatory properties. Zinc also works to stabilize cellular membranes with its antioxidant properties.

Copper: Like zinc, copper is another mineral and key nutrient for a healthy immune system. Copper also works synergistically with zinc to maintain cellular health.

As stated in the beginning, to support a healthy immune system for your horse, it is critical every owner has a proper vaccination program in place. It is also very important to have a solid deworming program. If you have any questions, reach out to your veterinarian.

To further support your horse’s immune system above a standard daily diet, especially for horses that are under stress, we recommend top-dressing Essential K®, which will provide your horse with a boost of nutrients that support a healthy immune system.

If you have any concerns about your horse or would like to see if they need any additional nutritional support for their immune system, feel free to reach out to us so we can answer any of your questions.

Chris J. Mortensen, Ph.D.