White blocks generally contain salt only, while colored blocks typically contain both salt and minerals. With so many choices, it is imperative to choose a product made specifically for horses. Never use a product created for cattle or multiple kinds of stock. Indeed, each species has different needs, and what is good for one can be harmful to another.
When choosing salt and minerals for horses, read the labels carefully and choose a supplement that corresponds to the needs of your area. For instance, there are regions of the country that are deficient in selenium and, thus, require additional supplementation. Meanwhile, other regions have excessive selenium in the soil – and adding more to the horse’s diet could result in toxicity.
While blocks are convenient and easy to use, loose salt and mineral are actually better for horses, which, unlike cows, grasp food (or any substance) with their lips rather than their tongues. Although horses that eat a balanced diet don’t generally have salt or mineral deficiencies, make them available throughout the year – not just during the warmer months of spring and summer.