Poor hoof horn quality is not always a sure sign of a deficiency due to the forage. For example, when the front hooves are brittle and cracked while the hind hooves the coat, the long hair
are of good quality the reason is most likely not the forage. However, if the horn quality is poor on all four hooves and the coat is dull or shaggy, it may be advisable to change the diet. The feeding and its influence on the horse should be looked at holistically and possibly together with the veterinarian.
The following components are contained in both basic as well as supplementary feed, therefore, it’s not always necessary to add supplements which might in some cases only lead to oversupplying.
When it comes to hoof horn quality it should be taken into account that it takes about a year for the newly formed horny cells to grow from the coronary band to the sole. The use of horse hoof boots for riding could be therapeutic on a vulnerable hoof during this time.
Protein deficiency can significantly slow down the growth of hoof horn while the opposite effect, an accelerated horn growth can be caused by an overload of protein. However, the accelerated growth tends to result in weak horn quality. Generally only few horses suffer from too little protein in the diet. It's more likely that they are consuming too much protein in the form of lush grass or high protein feed.
Probably the best-known food supplement for the equine hoof is biotin also known as vitamin B7 or vitamin H. Since horses produce a considerable amount of biotin themselves, supplementary feeding is not necessary in most cases. However, in horses with a disposition for brittle and cracking hooves a continuously high biotin supplement can lead to improvement.
Vitamin A (carotene)
Vitamin A is important in equine diets because of its powerful antioxidant nature. Vitamin A is synthesized in the horse’s intestine from beta-carotene which is abundant in fresh forage, therefore, grazing horses are usually well supplied. This vitamin is stored in the horse’s liver and usually supplies a horse through the winter months when there is no fresh grass available. A vitamin A deficiency may cause night blindness, watery eyes, bone and muscle growth defects, a dull coat, reproductive problems, and increased susceptibility to disease and infection. In horse hooves a deficiency leads to brittle, cracked horn and the formation of fissures. Fortunately, the feeding of carotene is very easy. It can be found in any green forage. Only during the winter months the supply of hay and oats is not sufficiently covered. However, the deficiency can easily be compensated with carrots or supplementary feed.
Selenium must be added to the feed of many horses. However, toxicity causes defects in the hoof wall and brittle horn material. An extreme oversupply leads to a vulnerable hoof wall and can cause swellings on the coronary band as well as horizontal rings in the hoof wall.
In contrast to selenium, low zinc supply has a negative influence on the hoof and therefore it is commonly an added supplement in the feed. Zinc plays both an activating and a regulatory role in the keratin production which is crucial for healthy hooves. Because zinc oxide can only be metabolized in small amounts it is important that zinc is included in the diet either in an organic compound or as zinc sulphate.