The horse’s immune system is always busy. Even when the horse is healthy it is performing its background functions of removing dead or damaged cells, guarding all the mucus membranes that are portals into the body from the outside world (intestinal tract, eyes, respiratory tract, genitourinary tract), and reacting to any organisms or foreign substances that make it past the body’s barriers of skin and mucus membranes.
The immune system is never inactive, but in health it performs all these functions silently without any outward signs. Let a serious challenge come along though and it’s like poking the bear. The signs of a fully activated immune response come to the surface such as fever, muscle and joint pain, lethargy, inflammation. When stimulating the immune system, be careful what you wish for!
As with all body systems, there is a network of checks and balances for the immune system to keep reactions in check. This is termed homeostasis. For optimal functioning there must be support of all arms of the immune system, including reactions to regulate the responses.
The first step in supporting a strong immune system is nutrition. The horse needs both adequate quality protein and sufficient calories to maintain a normal body condition. On the vitamin and mineral end, B vitamins, vitamin A, vitamin E, vitamin C, magnesium and the trace minerals selenium, zinc and copper are particularly important to both vigorous reactions and the control countermeasures that keep them in check.
Immune system activity generates large amounts of reactive oxygen species (ROS), also known as free radicals or pro-oxidants. Damage to surrounding tissues and the immune system cells themselves can result from this friendly fire. The antioxidant vitamins, glutathione, N-acetyl-cysteine and enzyme systems such as copper and zinc superoxide dismutase are the body’s first line of defense against these but the protection can be boosted by other plant based sources of antioxidants such as citrus bioflavonoids, brightly colored fruits plus herbals like Turmeric and Pau d’Arco.
Spirulina is a powerful antioxidant and also demonstrated to support the production of protective IgA antibody along mucus membranes rather than the IgE that is associated with allergic reactions.
Some herbs are well documented to support the maintenance of both a protective and balanced immune system, including Echinacea, Ginseng, Astragalus and arabinogalactans from Larch. Other naturally occurring products support alert defenses by providing gentle stimulation to the rich immune system of the intestinal tract – the GALT or gut-associated lymphoid tissue. These include the beneficial strains of probiotic organisms and mannanoligosaccharides from the cell wall of Saccharomyces cerevisae yeast. Cells originating from activity in the GALT communicate with the immune system throughout the body.
From directly battling disease to enabling robust responses to vaccines, the time to think about immune system support is at least 4 weeks before the challenges may come along. By properly fueling the immune system in advance it will be prepared to defend your horse in the best way possible.
Eleanor Kellon, VMD