The role of nutrition promotes hoof wall growth, integrity of the hoof tissues and maintains structural integrity of the foot, all come from a well-balanced diet.“You can’t have a healthy foot without a good farrier, and a farrier can’t do a good job without a healthy hoof.” – Gravlee
Many factors can affect hoof growth, including genetics, health, exercise, environment, mechanics, farriery and nutrition. The reason nutritional deficiencies show up in the hoof so often is due to hoof being a very metabolically active tissue. The hoof wall of a normal adult horse grows at a rate of approximately 6 to 10 mm per month. As this hoof is being worn away it must constantly be replaced.
Deprived of nutrients, the hoof grows more slowly, and the horn that is produced will be weaker and of poorer quality. Nutritional influences that affect hoof growth include energy intake, protein and amino acid intake and metabolism, minerals such as zinc and calcium, and vitamins such as biotin and vitamin A. It is important that all key nutrients are present in the correct amounts. If the horse is lacking in one or more of the nutrients, hoof quality and growth will be compromised.
Meeting energy requirements may be the first and most important step in ensuring hoof growth and functional integrity. A horse in negative energy balance will utilise protein in the diet or body to make up energy needs for maintenance or growth. This may create a secondary protein or amino acid deficiency.
The hoof wall is approximately 93% protein on a dry matter basis. Horses which take in too little protein have slowed hoof growth and tend to produce inferior quality horn that is prone to cracking and splitting.
The composition of the hoof wall is predominantly an insoluble protein called keratin. Keratin, like all proteins, is made up of a chain of amino acids. The amino acid cysteine accounts for as much as 24% of the total amino acids in keratin. Methionine, an essential amino acid, is also present in keratin but only in small amounts. The role of methionine in hoof formation is in producing cysteine, as the horse has the ability to convert dietary methionine into cysteine.
The amino acids methionine and cysteine both contain sulfur, which is an essential element in the formation of keratin. The sulfur components of these amino acids form strong cross links between the collagen fibres during hoof formation. The more cross-links formed the stronger the resulting hoof wall.
Diets deficient in methionine will cause a cysteine deficiency, leading to weakened hoof growth. Supplementing with methionine will increase cysteine levels within the hoof capsule and along with other co-factors will improve hoof growth and quality. Methionine also helps increase the bond between the laminae of the hoof wall and so is important in preventing, managing and treating laminitis.
Young, growing horses, mares in the latter stages of gestation and lactating broodmares have high protein and energy requirements. If protein requirements are not met hoof growth and quality will be compromised.
When evaluating the diet and making recommendations relative to nutrition, assessment of the adequacy of the diet in all macro and micro minerals should be considered. Remember that the health of the foot is an extension of health of the horse and that if mineral deficiencies compromise horse health in general, then the health of the foot is also going to be negatively impacted.
Zinc is present in high concentration in normal hoof tissue and is critical for a variety of functions, including the formation of keratin. A zinc deficiency can cause slow hoof growth, thin walls, weak connections and weak horn. Zinc also plays a role in minimising hoof abscesses and hoof diseases.
Copper is important in hoof formation as it is required for the activation of the enzyme which forms the sulfur cross links that hold the keratin strands together.
Excess selenium in the diet can interfere with keratin formation. Selenium will actually replace the sulfur and form its own cross links. Selenium cross links are much weaker and the corresponding hoof wall will also be weak.
Calcium is essential for the cohesion of one cell to another, and it is thought to play a role in the cross linking of collagen strands in hoof.
Vitamin A, Vitamin D, Vitamin E, and biotin are very important in hoof nutrition. However since all of the B vitamins are involved in some way with protein, fat and carbohydrate metabolism and interactions, they play very important roles in a tissue as active as the hoof.
Biotin has received more attention in terms of hoof growth than any other nutrient. Biotin is a B-complex vitamin that is generally produced by bacterial growth in the horse’s hindgut in sufficient amounts to meet nutritional needs provided the horse has access to quality pasture. Biotin deficiencies cause skin lesions, sparse hair growth, dry, scaly skin, and brittle, cracking hooves. Hoof deformities such as dishing and low heels have also been associated with biotin deficiencies.
Studies have shown increased hoof growth and improved hoof quality in horses supplemented with biotin at 15-20 mg per day and seems to be most beneficial to horses with thin, brittle hoof walls and tender, thin soles.
Fatty acids are used to protect the outside of the hoof from moisture damage. Fatty acids protect the hoof wall that already exists, but are not involved in the inherent strength of the hoof wall. When present in correct amounts in an unbroken layer, these seal moisture into the deeper hoof structures and seal water out.
Grass is a rich source of the essential fatty acids linolenic (omega-3) and linoleic acid (omega-6) in a ratio of from 4:1 to 6:1. For horses on hay based diets, supplementing with flax seed oil will provide the essential fatty acids in the same ratios as grass.
If nutrition is suspected as being the cause of a particular hoof problem it is advisable to consult a nutritionist and have the forage analysed and the overall diet assessed. Many minerals are interrelated and a fine balance exists. Over supplementing on certain minerals can be as harmful as under supplementing. There is also the cost factor involved with over supplementing or supplementing unnecessarily.
Commercially available hoof supplements can correctly balance the diet targeting the common deficiencies associated with poor hoof growth. Improvements in hoof growth and quality should be apparent within 8-10 weeks after the supplement has been started. If this is not the case then either nutrition is not a factor or the hoof supplement used was not the right choice. If the supplement is working it is advisable to keep using it for at least 9 to 12 months as this is how long it takes for a complete new hoof capsule to grow.
Promoting hoof wall growth, integrity of the hoof tissues and maintaining structural integrity of the foot come from a well-balanced diet that meets the horse’s requirements for all nutrients. The horse’s feet are a sensitive indicator of nutrition overall.