Because of the difficulty in establishing the nature and extent of deficiencies, it is common practice to supplement with a wide range of minerals and vitamins.
However, if you are tempted to use a supplement, consider carefully whether you might be harming the horse. Usually this will not be the case, but you are probably not doing anything helpful, either.
Supplements are useful when a definite deficiency is established, but, in some cases, may be harmful if it is not.
For example, you might be tempted to supply extra selenium if your horse ties up easily. However, the horse may not be deficient and the extra selenium may be dangerous, causing the horse to develop severe laminitis.
A routine blood test will often help to establish the extent of a horse’s deficiencies.
A variety of foods are likely to provide trace elements and vitamins, so herb and meadow supplements may be a logical dietary supplement. Garlic used for parasite control is said to be beneficial, but feeding too much of a product containing onion may be harmful.
Most horses cope well on a good-quality mixed diet, fed at a level appropriate way to the work done. Supplementation needs to be used sensibly with an understanding of the way it is used in the body.
We do not yet know enough about the horse to be dogmatic about any particular additive, but, above all else, we should take care to do no harm.