Vitamins and supplements

With vitamins and supplements it is not only the dose that matters, but the form — and sometimes knowing when not to give something at all. A few insights.

The form of Vitamin E matters as much as the dose

Ordinary dry Vitamin E powder is poorly absorbed by horses. A water-dispersible natural form reaches five to six times higher blood levels at the same dose — which is critical for horses with genuine deficiency or nerve and muscle disease. When Vitamin E really matters, the form is not a detail.

Adding oil to the feed raises the Vitamin E requirement

Feeding oil increases oxidative stress, so a high-oil ration needs proportionally more Vitamin E. Many owners feeding oil for condition or for muscle conditions don't realise their horse now needs extra Vitamin E to match.

Selenium and Vitamin E work as a pair — assess them together

Selenium and Vitamin E share antioxidant duties, and being short of one increases demand for the other. They should always be looked at together, never in isolation.

Biotin for hooves takes 9–12 months to show

Biotin does have genuine evidence behind it — but only for horses that already have poor-quality horn, and it takes the best part of a year of steady supplementation before a whole new hoof wall reflects the change. Patience, not a quick fix.

Horses make their own Vitamin C

Unlike people, horses manufacture their own Vitamin C, so routine supplementation in a healthy horse has no evidence base. It may only be worth considering in horses under severe illness or oxidative stress, where the body's own production can be overwhelmed.

Avoid Vitamin K3 (menadione)

Vitamin K1 and K2 are safe in horses, but the synthetic form Vitamin K3 (menadione) is toxic to the equine kidney — and it still appears in some older injectable vitamin products. Any product containing menadione should never be given to a horse.

This is general information. It does not replace the individual feeding plan your EVN vet prepares for your horse after assessing it.