Vitamin requirements and supplementation in athletic horses

Abstract

In the preparation of this paper, studies on the vitamin requirements of performance horses were reviewed. According to several studies and in line with current NRC recommendations, the core requirements of many vitamins do not appear to be much higher in performance horses than in horses at maintenance, and any increase in requirements should be compensated for by the increase in appetite and daily feed intake associated with the increased workload. This suggests that exercise per se does not seem to have any major influence on the vitamin needs of horses. The requirements for water-soluble vitamins normally can be assumed to be met by typical equine rations in combination with the synthesis of vitamins in the body. However, if the vitamin contents of the basal feeds are reduced and/or the microbial vitamin synthesis of the horse is compromised, there may be need for additional vitamin supplementation. Lack of sunlight and access to pasture may also affect vitamin status and therefore the need for additional supplementation. In addition, the intake of some vitamins may be inadequate when forage-limited diets or forage rich diets (especially preserved forages) are fed. Processing and storage can affect the content of many vitamins in feeds and forages. With respect to the active exercising horse some vitamins may have additional health benefits such as support for healthy airways and the immune system, which may influence the performance capacity of the horse and raise the requirements. Perhaps the most accurate recommendations can be given for vitamin E, whereas the recommendations for other vitamins are more approximate. In the new, sixth revised edition of the NRC (2007) all vitamin recommendations are unchanged compared to the previous edition (NRC 1989). However, our review has highlighted the need for more research into the influence of vitamins on the performance of horses in intense exercise especially with respect to the B-complex vitamins.