Biotin is one of the eight B vitamins that play essential roles in virtually every organ and cell of the horse’s body. Biotin is part of several major enzymes involved in glucose metabolism, fatty acid production, and also serves as an intercellular “glue.”
Biotin is also significant in promoting cellular growth and proliferation in rapidly dividing tissues, making it critical for skin and coat health as well as healthy hooves.
The B vitamins, including biotin, are water-soluble and float freely through the fluids of the body without being stored in any body tissues.
Once absorbed into the bloodstream, the B vitamins will circulate and be taken in by cells as needed or eliminated in the urine. Because of this relatively rapid usage and elimination, horses should ingest B vitamins on a consistent, daily basis. Biotin is synthesized by gut microbes and derived from dietary sources including grains, brands, and yeasts.
Role of Biotin in Horse Health
Biotin has become commonplace in feed rooms across the world because of its reputation as an effective hoof supplement. Like the more familiar niacin, riboflavin, and thiamin, biotin is a B-vitamin. Biotin is similar to other B-vitamins in that it is essential in the conversion of feedstuffs to energy so horses can grow, work, and reproduce.
Biotin is found in virtually every cell in the body and is an essential coenzyme in carbohydrate, fat, and protein metabolism. This B-vitamin is also important for normal thyroid and adrenal gland function, reproductive tract health, nervous system stability, and most dramatically, growth and repair of skin and hooves.
Biotin occurs naturally in many feedstuffs commonly fed to horses such as oats, soybean meal, alfalfa, rice bran, and molasses. However, horses derive most of their biotin requirement from the fermentation of forages by the microbial population in the hindgut.
Interestingly enough, speculation surrounds exactly how much of the biotin produced in the lower portion of the digestive tract can be absorbed, as the hindgut is typically an inefficient zone for nutrient uptake. In fact, only water seems to be absorbed well from the hindgut.
Further, any factor that interferes with the normal functioning of the microbial environment would affect biotin synthesis, resulting in less biotin availability. Biotin presented in the diet may have a better chance of being absorbed as it passes through the upper portion of the digestive tract, where the majority of vitamin and mineral absorption occurs.
For this reason, commercially produced biotin and other B-vitamins are often added to high-quality horse feeds. The amount typically found in feeds and produced by microbial fermentation is enough to prevent any outright biotin deficiency.
Biotin content in fortified feeds is typically less than 1 mg per day when feeds are given at recommended amounts. Hoof supplements, on the other hand, offer 5 to 25 mg of biotin per daily serving.
Biotin Deficiency in Horses
Extreme, life-threatening deficiency symptoms for biotin, or any of the B vitamins, is not likely to develop in horses on normal diets as the intestinal tract is capable of manufacturing these vitamins and some will be bioavailable and absorbed by the horse.
Steps for a Healthy Hooves
- Farrier Work – Regular Visits – Trimming – Level
- Exercise – Increases Blood Flow to Hooves
- Environment Protection – Clean Dry Bedding
- Hoof Nutrition – Ask Your Veterinarian – Farrier
Symptoms of Lack of Biotin
- Brittle Hoof
- Dry Skin
- Poor Coat
- Slow Growth
- Poor Health and immunity
However, there can be symptoms of inadequate amounts of biotin that include brittle, shelly outer hoof horn, dry skin, and a poor, dull hair coat. There is evidence that biotin supplementation may be particularly useful in improving hoof quality with regards to hardness, integrity, strength, and even growth rate.
In horses, this sulfur-containing vitamin is believed to be especially important in hoof health as a deficiency of biotin may result in reduced hoof quality, manifesting as a thin and friable hoof wall prone to cracks, crumbling, a soft white line and tender feet. Providing at least 20 mg of biotin per day for an average mature horse can help strengthen hooves and increase the rate of hoof growth.
Effect of Biotin on Hoof Growth/ Slow
Hoof growth is a slow process. The equine hoof wall takes approximately 9-12 months to grow from the coronary band to the weight-bearing surface. Studies have shown that daily supplementation with 20 mg of biotin improved hoof wall integrity following at least 9 months of supplementation.
Longer supplemental durations improved hoof structure and hoof wall tensile strength. Supplemental biotin should be fed for at least 6 to 9 months on a daily basis. Biotin only improves the growth of new hoof horn, not existing hoof. Because of this, the results of biotin supplementation took eight to 15 months to complete, depending on the growth rate of the hoof. This is the length of time necessary for the hoof wall to completely grow out and replace itself.
Throughout some studies, differences were noted in hoof growth rates among numerous breeds as well as individuals, and several factors were thought to cause contrasts in growth. Colder environmental temperatures slowed growth, as did high body temperatures. Other conditions accelerated growth.
For instance, the additional concussion experienced by the hooves of horses in regular work may increase the growth rate. In other studies, biotin supplementation did not change the growth rate, but the quality of the hoof improved. Hoof quality was determined by measuring hardness, integrity, conformation, and tensile strength (the ability of the hoof to withstand pressure from spreading).
One study found growth rates and hardness were greater when horses were dosed with 15 mg per day than with 7.5 mg per day. Intermittent feeding of biotin did not result in rings on the hooves, but if biotin supplementation ceased altogether the hooves regressed to their former state. If the dose was decreased below recommended levels, there was the deterioration of hoof quality but a not complete reversion to the state observed before biotin supplementation began.
Researchers are unsure how biotin helps the hoof, but the actual improvement seen from doses of 20 mg per day has been documented by electron microscope examination. The hoof horn is made up of keratinized cells arranged spirally to form long tubules that run from the coronary band to the end of the toe. As the cells thicken around the tubules, the hoof horn becomes more resilient to damage.
Once biotin has been mixed with other ingredients, particularly oils and other fats, it has a relatively short shelf life, around six months from the time of manufacture.
Buying fresh produce and using it up within this time frame is the best way to ensure maximum results from a biotin supplement. Since there are no government controls on the manufacture of equine supplements, it is important to buy from a reputable dealer to guarantee that the amount promised on the label is indeed in the product.
In order to achieve maximal improvement in hoof health, a horse should consume a minimum of 15 mg of biotin per day. If improvement has been seen within eight to 15 months, the horse will need to remain on biotin the rest of its useful life to maintain that improvement.
Cutting the dose is not advisable because it may affect the results, and care should be taken not to buy more than what can be used up in six months. Other nutrients such as zinc, methionine, and iodine can also affect hoof quality.
Nutrients Important for Hoof Health
The general diet needs to contain enough energy or calories to sustain growth.
Good-quality protein that provides adequate levels of amino acids, particularly lysine and methionine, is necessary as the hoof wall is over 90% protein on a dry weight basis.
Fatty acids connect hoof horn cells and sustain a permeability barrier. Minerals should be balanced with special attention to copper and zinc, which are both associated with hoof quality. Zinc is needed for normal cell division involved in the growth and repair of the hoof wall. Copper is needed for enzymatic function in rapidly dividing cells such as hoof cells.
Horse Breeder Associations
|Blacksmith Association of North America||United States||ABANA|
|Applacia Charter of BlackSmith||United States||AACB|
|Horse Breed Associations Resource||United States||EQUUIS|
|United States Horse Breeder Association||United States||USSHBA|