We’re all familiar with hoof dressings and polishes, but there are also several products that claim to seal or strengthen the hoof and protect it from softening, infections, chipping, and cracking. These products do have their place, but we don’t believe they’re for every horse.
Nature equipped horse’s hooves with their own protective mechanisms. The hoof wall contains waxes and fats that form a solid protective barrier, preventing the loss of moisture to the outside at the same time they prevent easy uptake of moisture. Both the thin, outer coating on the hoof (stratum externum, aka periople) and the more dense portion of the hoof wall (stratum medium) contain these waxes and fats in varying proportions. As long as that barrier remains intact, overly soft or dry feet usually aren’t a problem.
When barefoot horses aren’t properly and regularly trimmed, hooves become overgrown, hoof walls flare and eventually the hoof can chip and crack. This mechanically breaks the natural protective seal. The seal is also violated somewhat by shoeing nails and even trimming itself, although these are both necessities. Rasping the wall to remove any ridges also strips away the natural protection. Rasping should be kept to a minimum.
Advertisements for a variety of hoof treatments, including the sealers and strengtheners, point to environmental factors such as ammonia (from urine) and either too much or too little moisture. Fact is, a healthy hoof is able to withstand even extreme conditions when it comes to moisture. Horses adapt quite successfully to everything from Arabian dessert conditions to the salt marshes of France’s Camargue.
In fact, a 1998 study at the University of Edinburg showed blocks of hoof wall from healthy feet could be either baked in an oven or soaked in water for 2 weeks, or both, and still retain a strong outer barrier. Some swelling/softening of the outermost layers of the hoof wall can occur with prolonged submersion in water, but once out of the water the hoof quickly returns to its normal consistency — just like our own fingernails get soft with a long tub soak but return to normal once out of the water. Water, or lack of it, is not the enemy.
Urine is another story, however, with urea, ammonia and sulfide ions all capable of causing swelling and softening. But, unless the horse constant stands in urine, this is unlikely to be a major issue.
While the environmental assaults on the hoof wall usually are exaggerated, some horses naturally don’t produce horn of sufficient quality to protect them. There’s usually that one horse in the barn with chronic problems with brittle, shelly feet, while other horses, on the same management,have good feet. How much of this is genetically determined poor hoof quality and how much is related to different individual requirements for nutrients important to a strong hoof is unknown.
The point is, however, that any combination of factors can result in problems with hoof quality leading to excessive chipping, cracking or difficulty keeping shoes on. These are the horses that may be candidates for hoof sealants/strengtheners, if correcting the other risk factors doesn’t work. If fixable problems related to insufficient hoof care or nutrition are found, the hardeners or sealants may be useful for at least short-term use until the damaged portions of the hoof can grow out.
Hoof sealing and strengthening products act in one of two ways. Sealants replace/reinforce the natural water and chemical-repellent substances with other ones that do the same thing. Hardeners work by reacting with proteins in the hoof wall to form chemical bridges between them that make it more difficult for water and other materials to gain access to the deeper layers. Products based on formalin/formaldehyde and glutaraldehyde fall in this category.
We tried these products on barefoot broodmares with neglected feet and problems including chipping/cracking, tender soles and weak heels. The mares were on turnout in a field where conditions varied from dry to marshy. Testing weather included both prolonged periods of rain and high heat.
We found hardeners do work, but the effect is temporary. You need to reapply frequently — every few days to a week. The volatile bases in these products also strip off natural oils/fat/waxes in the hoof. This helps the products adhere better, but we think it results in an unnecessary damage to areas of the hoof that are healthy.
We would use these products only on problem areas. Be careful, though, as you can overdo it on the soles, and a buildup of a very hard sole is uncomfortable for the horse to walk on.
We ran into this problem with one mare, but it resolved itself when the dry, hard sole cracked and sloughed.
We found that once the hoof could be stabilized so that damaged portions could grow out, the improvements held as long as the mares were trimmed often enough and correctly. Both Keratex Hoof Hardener and Crossapol hardened hooves, but on examination of hoof trimmings, the Keratex seemed to penetrate deeper with a gradual transition between the extremely hard outer layers and the inner horn.
With the Crossapol-treated hooves, there was a sharp transition between a thinner layer of hard horn and the deeper wall.
The hardeners are the best choice for horses with tender soles, and we prefer Keratax.
Of the sealants, the only one we felt was tough enough to really protect against chipping was Mustad’s Tuff Stuff. As with the hardeners, you’ll need to reapply often, usually every few days.