Hoof supplements are big business. It only takes a glance around any tack shop or feed store to see that they're everywhere - all with catchy names and lists of ingredients as long as your arm, all purported to help your horse grow tougher, shinier, more durable hooves. It's natural that we look to nutrition to address our horse's pedal infirmities, but what do really know about how nutrients translate into hoof horn?
Some of the feed ingredients promoted as hoof strengtheners do, in fact, have some dependable research behind them; others are based only on folklore. Let's have a look at where your money might best be spent.
Feeding the Feet
An inadequate diet eventually will make itself felt throughout the horse's body. He'll usually have a dull, staring coat, poor muscle tone, no energy, and the growth of his hooves will be slower than normal, resulting in splitting, cracking, and difficulty holding a shoe. Provide an undernourished horse with a complete and balanced diet, and all of those conditions probably will correct themselves. He'll grow better hoof horn and produce it faster, because his body is being supplied with the necessary raw materials.
Sometimes, though, horses grow shelly, crumbly hooves even when they have an adequate diet. To some extent we can blame genetics; while we have been busy selecting for qualities like speed, fancy movement, or jumping ability, we have neglected to breed specifically for good feet, and certain bloodlines do exhibit consistently poor hoof quality. But it's also possible that we don't yet fully understand which nutrients contribute to quality hoof growth - so our horse's diets may not be quite as correct as they appear.
Benefits of Biotin
The search for a 'recipe' for more resilient hooves is nothing new. But biotin, a B vitamin, has received most of the attention during the past couple of decades.
As a nutrient, biotin is involved in glucose metabolism, the processes of cell growth and division, and the utilization of other B vitamins such as niacin. And because it contains sulfur, an element needed for the formation of the reinforcing bonds between strands of collagen, biotin plays a role in the health of all connective tissues as well as the hair coat and the hooves.
Reliable research supporting the use of biotin to encourage better hoof growth in horses has been slow to surface. Most of the reasoning behind supplementing equine diets with this vitamin comes from studies in other species. In many animals, various types of hoof and/or foot lesions have been successfully treated by supplementing biotin, so it's a reasonable assumption that it might do the same in horses, but it's only in the last 10 years or so that research has confirmed this suspicion.
In a 1991 study, for example, 42 Lipizzan stallions at the Spanish Riding School in Austria participated in a double-blind examination of biotin supplementation. Over two years, 26 of the stallions received 20 mg of biotin daily in their feed, while another 16 stallions received a placebo. The conditions of the horses' hooves - which had been crumbly, thin, and had a tendency to crack at the weight-bearing border - showed significant improvement after they had been on biotin for nine months. There were fewer hoof cracks, less crumbling of the horn and greater measurable tensile strength. This and other similar studies have at last demonstrated that there's something to this biotin stuff.
Feeding biotin at a level that has an impact on hoof growth is not really a matter of correcting a deficiency. In essence, it's taking a nutrient and feeding it at a level beyond normal requirements, at which it really becomes a therapeutic medication. Fortunately, biotin, like all B vitamins, is water soluble, which means it's not stored in the horse's tissues. The body uses what it needs and eliminates the rest in the urine. So there's very little chance of a horse developing biotin toxicity.
Some horses with poor quality hooves respond positively to biotin supplementation, but not all do - and what separates the horses that respond from those who don't isn't yet clear.
Other Hoof-Building Supplements
It takes more than biotin to build a better hoof. Several other dietary ingredients may influence the formation and strength of the protein called keratin, which makes up most of the hoof wall. Sulfur-bearing amino acids, including methionine, are largely responsible for the cross-linking that helps give the material sturdiness and resiliency. There's very little hard data about the specific requirements of methionine in the equine diet, but it seems reasonable to supplement this amino acid if poor hoof quality is a problem. And indeed, you'll find methionine listed on the label of many hoof supplements.
Another nutrient that has been implicated in hoof quality is zinc. This trace mineral is involved in the health and integrity of hair, skin, and hooves, and some nutritionists suspect that the majority of equine diets are deficient in this nutrient. Zinc is present in most horse feeds as well as in hay, but at levels too low to meet the recommended levels for good health. For this reason, most commercially mixed feeds have supplemental levels of zinc added.
Other nutrients that may play an indirect role in hoof quality include fatty acids, manganese, selenium, vitamin C and other B vitamins. Be careful, however, not to over supplement selenium. This trace mineral is important as a partner with vitamin E in immune function, but it has a very low toxicity level. At levels as low as 3.3 mg/kg of feed, selenium can be poisonous - and in addition to symptoms such as a loss of hair from the mane and tail, it can cause the hooves to separate at the coronary band and slough off.
Giving your horse a hoof supplement won't provide an instant fix. You can't repair a cracked or crumbly hoof, you can only try to encourage better growth from the coronary band down. Most horses grow new hoof wall at a rate of a quarter to a third of an inch a month. So if there's improvement in the quality of the hoof, it takes from six to nine months, on average, to make its way down to the point where your farrier can trim it. If you haven't seen a better hoof after your horse has been on the supplement for a year, it may be that he isn't going to respond to it.
Given in the recommended doses, most hoof supplements will not hurt your horse, but beware of feeding higher levels than suggested on the label or doubling up with multiple supplements. Feeding too much of some nutrients can do more harm than good. Excess sulfur, for example, blocks the production of collagen, the exact opposite of what you want to achieve.
Work With a Farrier
Most important, don't expect supplements to take the place of a knowledgeable farrier. Regardless of the quality of his hoof horn, no horse is going to have functional feet if he's left for months without correct shaping and trimming of his hooves.