The Importance of the Equine Immune System

A healthy immune system is necessary for your horse to withstand stress in the environment and protects the body by identifying and neutralizing foreign agents. Training, competition, travel, and/or aging can all cause imbalances that result in compromised immune function. Understanding how the immune system works can help keep your horse feeling and performing their best.

How the Immune System Works

The primary role of the immune system is to defend the body against foreign invaders or abnormal cells that invade or attack it. The immune system is a complex network made up of white blood cells, antibodies, and several organs that trap microorganisms and foreign substances and provide a place for immune system cells to interact and generate an immune response. A normal immune response consists of recognizing a foreign antigen, mobilizing forces to defend against it, and attacking it.

Physical Barriers

The first line of defense are physical barriers such as the skin and membrane linings of the respiratory and digestive tracts. As long as these barriers remain intact, invaders cannot penetrate them. Once broken, risk of infection increases. These physical barriers are defended by ‘good’ bacteria that live in the area and secretions containing enzymes that can destroy harmful bacteria. Research indicates that over 60% of immune function resides in the GI Tract due to the lymphatic tissue surrounding it. It is often said that digestive and immune health go hand in hand.


Immunity can be recognized into two separate categories: nonspecific (innate) immunity, which is present at birth, and specific (adaptive) immunity, which is acquired and improves over time. Non-specific immunity treats all foreign substances the same way, acute inflammation is most important process involved. This is where white blood cells rapidly travel into the tissues to kill invading organisms and remove injured cells. Specific immunity tailors its attack to a specific antigen in which has been previously encountered. As the immune system encounters various antigens, it learns the best way to attack and begins to develop a memory for each antigen. It takes time to develop after first exposure, but results in a quicker and more efficient response in future encounters compared to non-specific immunity.

Factors That Can Compromise the Immune System

With today’s day and age, there are many factors that can compromise the horse’s immune system, such as stress, nutritional deficiencies, and age. Stress can be physical or mental and can be caused by a wide variety of elements such as environmental factors, chronic conditions such as illness, gastric upset, competitions, hauling, injuries, metabolic imbalances, and/or regular training. Nutritional deficiencies can result in not consuming enough forage and/or low-quality feedstuff. This can also occur when commercial feeds are not fed according to the label instructions and/or lacking vital nutrients. And lastly a horse’s age can play a role into their immune health, as their metabolism decreases over time.

Optimal care of the immune system is critical for a favorable immune response that allows for effective defensives against infection. This can be obtained through proper nutrition, good care and maintenance, and making efforts to reduce your horse’s stress.

Ingredients that May Lend Support

Vitamin E (Natural):Vitamin E is considered the most important antioxidant and works closely with selenium to protect the body from the oxidative stress of exercise and illness. Natural E is approx. 2.5 times more bioavailable than synthetic vitamin E (4,000 IUs natural vitamin E approximates 10,000 IUs of synthetic vitamin E). Most studies/research indicate 8,000 IU’s -10,000 IU’s (or approx. 3,000-5,000 IU of Natural Vitamin E) during/post therapy for immune support.

Selenium is a trace mineral that along with vitamin E function together to help to protect body tissues from free radical damage that occurs during oxidation (the conversion of feedstuffs into energy).

Vitamin C (Ester-C®) Vitamin C is an antioxidant that helps protect the tissues of the body and also important in the production of connective tissues like tendons and ligaments. Ester-C® has up to 4X more metabolic activity than standard vitamin C (ascorbic acid). It is a unique patented ascorbate complex bound with calcium carbonate. Ester- C® is naturally processed in purified water without the use of alcohol or acetone solvents. This makes Ester-C® a more readily available, readily absorbed form of vitamin C.

Probiotics are live microorganisms (bacteria and yeast) that help promote healthy digestive function and support a healthy immune system. Often referred to as ‘good bugs’ they help break down ingredients/contents that the body normally can't, and help inhibit ‘bad bugs’ from growing.

Turmeric is a powerful antioxidant that helps combat oxidative stress and supports a natural inflammatory response for overall health.