Hoof-quality problems are common issues for horse owners. Chipping, splitting, flares, white-line problems, dryness, thin soles/walls and poor growth all usually have a nutritional component. Since hooves are easy to see, grow rapidly and take a lot of punishment, it stands to reason that one of the first places a dietary inadequacy shows up is in the hoof. That means you should consider feeding your horse a hoof supplement.
But before you run out to buy any old hoof supplement, you’ve got to know what your individual horse needs. If a particular nutrient is already present in the diet in good amounts, feeding more of it won’t help.
Fats are an important component of the hoof wall, forming a barrier that keeps water out and prevents the internal tissues from losing moisture. The most important hoof-wall fats are cholesterol sulfate and squalene, but these are easily synthesized by the horse. What the horse must consume are the essential fatty acids. The most important one for hoof health is omega-3. If the horse is on good pasture, he’s probably set, but if he’s on hay you’ll need to add flaxseed to provide good levels of omega-3. Simply adding 4 oz. of ground stabilized flaxseed or three tablespoons of flaxseed oil should cover your bases there.
Since the hoof wall is over 90% protein, look first at the amino acids. Alanine, glycine and cystine are the major amino acids in the hoof wall, and the horse can manufacture two of these himself, through exercise (alanine) and glucose production (glycine). Cysteine, however, is produced by the body from methionine, and methionine is an essential amino acid. An "essential" nutrient is one that must be present in the diet. Your horse’s methionine intake needs to be 7 grams/day. Lysine, another important amino acid that is believed to affect hoof wall production, is deficient in many diets. Total daily lysine needs are over 20 grams.