We usually don’t consider our horse’s vitamin C needs in winter. But should we?
◆︎ What is vitamin C good for?
Collagen production: It is necessary for the creation of collagen, which is found in connective tissue, tendons, ligaments, cartilage, bone, and skin. Collagen is also found in horse hooves, including the basement membrane, laminae, and digital cushion.
Immune support: Vitamin C protects against oxidative damage. It also supports white blood cells. It stimulates the production and differentiation of lymphocytes, and enhances their function.
Aids in allergy support: It is anti-inflammatory and helps stabilize mast cells, to reduce an allergic response.
Helps reduce the body’s stress response: This is important to support the horse in cold-related stress, confinement stress, and breathing challenges from being in a barn and/or breathing cold air.
◆︎ Vitamin C availability
In the summer, when horses are on pasture, they consume plenty of vitamin C from the grass, just like they consume adequate vitamin E and omega 3s.
Horses that have transitioned to a hay diet find that their dietary vitamin C consumption drops, since vitamin C in hay rapidly oxidizes and degrades. On a hay diet, horses rely on their liver to create vitamin C. For young, unstressed horses, the amount created is sufficient. However, when horses are older, with health and stress challenges, the amount of vitamin C they create may not be enough for the challenges they face.
◆︎ Consider supplemental vitamin C:
➡ Hoof care: to help improve the integrity of hooves. It may be beneficial when you have laminitis or hoof pain, you want to increase hoof growth, or you have thin soles.
➡ Tendon or ligament injuries: Your horse is rehabbing from a tendon or ligament issue.
➡ Respiratory issues: Your horse has breathing issues from allergens (spring pollen or insect bites) or dust.
➡ Health: When you want to bolster the immune system because a virus or bug is going around or your horse has been physically challenged by PPID. Your horse is an older horse that has “old horse” issues, such as arthritis, lameness, overuse, muscle loss due to age, etc.
◆︎ Final note:
Sometimes supplementation is not enough. Consult with your veterinarian if your horse is not responding to supplementation as you would like. Your vet can give you an accurate diagnosis and treatment plan.
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Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay, MSc. 2025