Vitamin C (ascorbic acid)
Sources
Vitamin C is derived from glucose in several equine tissues.
Daily Requirements
Vitamin C is poorly absorbed from the diet. Horses not undergoing intense exercise programmes do not really need vitamin C from feed as their daily requirements are covered by by endogenous synthesis from glucose.
Deficiency
Old horses and high-performing horses undergoing high efforts and confronted with high levels of oxidative stress, should be considered to be supplemented with vitamin C due to a lack of intrinsic vitamin C synthesis.
Excess
Has not been observed in horses.
Important to know
It is assumed that there is a relationship between decreased blood ascorbic acid concentrations in horses and several diseases, including post-operative and post-traumatic wound infections, epistaxis, disorders of the upper respiratory tract, and performance insufficiency.