Many horses need more vitamin C than they can make themselves or get from feed and forage – especially seniors, those in heavy work, those with respiratory conditions, and any horse that has been stressed.
Vitamin C, or ascorbic acid, plays several roles in the horse’s body, including involvement in hormone synthesis, bone calcification and antioxidant functions. Unlike humans, horses can synthesize vitamin C from glucose within the body. For this reason, deficiency is very unusual, but when horses experience excessive stress their bodies may not produce enough.
Stressful situations may call for vitamin C supplementation. Supplemental sources of the vitamin are challenging – due to lack of intestinal absorption, more than three grams per day of vitamin C is necessary to elicit a change in blood ascorbate levels.