The Functions and Importance of the Equine Immune System

Equine Immune System Synovium Horse Health

The horse’s immune system is one of the body’s most important mechanisms. The function of the equine immune system is to kill harmful pathogens that enter the body, preventing infections and disease. A well-functioning immune system is therefore essential for the horse’s health. Several factors influence the function of the immune system, a balanced diet being one of them.

Linseed Oil pure cold pressed for horses
Equine Immune System with Synovium Horse Health

When foreign cells enter the body, the immune system is triggered to remove the foreign invaders. The equine immune system can be divided into the innate immune system and the adaptive immune system. Both types of defence mechanisms consists of several components including different cells and organs.

The Innate Immune System

The innate immune system is the defence mechanism that is present and active at birth. This form of defence includes physical barriers such as the skin, mucous membranes and the cornea of the eyes 1. An internal defence mechanism is also present in addition to the physical barriers, which include various cells, enzymes, and proteins important for killing unwanted pathogens 2. The innate immune system is the first line of defence. It is instantly activated when a harmful cell enters the body 3. Therefore, one of the main functions of the innate immune system is to trigger a rapid response when an infection arises in the body 4. The innate immune system alone can destroy a wide range of pathogens and limit their spread.


The Adaptive Equine Immune System

Unlike the innate immune system, the adaptive immune system is acquired and developed by the body as it encounters various pathogens. When the innate immune system is unable to kill certain pathogens, the adaptive immune system is triggered 3. The immune response, generated by the adaptive immune system, consists of immune cells and antibodies that specifically target harmful pathogens 5. Therefore, the main function of the adaptive immune system is to recognise and specify the difference between body cells and foreign pathogenic cells 3. After being infected by a pathogen for the first time, the adaptive immune system memorises how to respond and kill this specific pathogen 6. When the body is infected by the same pathogen again, the immune system can respond more quickly and is more effective.

Vitamins and minerals are essential for both the innate and adaptive immune system of the horse. They support physical barriers such as the skin but are also required for the production of immune cells 7. A balanced diet is therefore important to maintain and promote a healthy well-functioning immune system. Synovium Prefit contains essential vitamins and minerals, which all have important functions in the body. The addition of this supplement supports a balanced diet and optimises and supports the function of the immune system.

During or after illness, horses may benefit from additional nutritional supplements containing ingredients proven to have a positive effect on the immune system.

Vitamin C, E and Selenium

Vitamin C and E both function as antioxidants in the body. These vitamins can neutralise free radicals in the body, which has a positive effect on the immune system 8. A vitamin C or E deficiency, due to insufficient availability from the diet, therefore negatively affects the horse’s immune system.

Research has previously shown that in addition to Vitamin C, Vitamin E is also important for a properly functioning immune system 9,10. Petersson et al. (2010), conducted a study supplementing Vitamin E to the diet of older horses, with results showing that Vitamin E supplementation supports the adaptive immune system by increasing the bacterial killing capacity of the immune system. Other study results suggested that supplementing Vitamin E combined with Selenium also has a positive effect on the immune system 11.

Synovium Myocare-e contains high levels of natural ( d-alpha tocopherol) Vitamin E and Selenium to support the immune system.

Linseed oil and Omega-3 Fatty Acids

Linseed oil is a plant-based oil that contains the ideal balance between Omega-3 and Omega-6 fatty acids. Fatty acids have essential functions in the body and are required, for example, for the absorption of fat-soluble vitamins. Additionally, Omega-3 fatty acids possess anti-inflammatory properties within the body 12. The anti-inflammatory effect promotes immune system function by supporting inflammatory responses in the body 13.

Synovium Linseed Oil is a product containing Linseed oil from the first cold pressing. The plant-based oil contains the ideal balance of Omega-3 and Omega-6 fatty acids, providing the required support to the body.


Probiotics are live microorganisms that promote and support a healthy and well-functioning hindgut microbiome composition. The balance of the hindgut microbiome is strongly related to the immune system. A dysbiosis of the equine hindgut microbiome, for example, due to sudden dietary changes or a diet containing excessive amounts of starch and sugar, negatively affects the immune system 14. A commonly used probiotic for horses is Saccharomyces cerevisiae, better known as brewer’s yeast. Lucassen et al. (2021) supplemented brewer’s yeast to the diet of eleven two-year-old horses before vaccinating them. The study’s findings indicate that adding brewer’s yeast to a horse’s diet can have a beneficial impact on its immune system. The yeast helps to speed up the initial immune response when the horse is exposed to a pathogen, resulting in a faster and more effective neutralisation of the pathogen 15.

Therefore, Synovium Immunomodulator contains a high-quality probiotic yeast that positively influences the function of the immune system. This supplement, in pelleted form, is suitable for horses that require immune support, for example during or after experiencing illness.

The Functions and Importance of the Equine Immune System - Synovium Horse Health
The functions and importance of the Equine Immune System


Equine Immune System – Article by Synovium Horse Health head nutritionish Anouk Frieling, Master Equine Sciences



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