It was the wet weather that caused me to miss the last hunt, I’m sure. After a week or more of almost continuous rain, Freedom abscessed after a hunt. Even though he was wearing hoof boots I think that his hooves were so soft after standing in mud, that he bruised through the boots!
Horses hooves are not designed to be wet all the time. Since the hoof is porous, it absorbs moisture from the environment to the point where the hoof loses it’s structural integrity. In other words, it gets soft. Then it expands and becomes susceptible to bruising, and both bacterial and fungal infections. When it dries, it contracts, which can cause cracking.
An article on http://www.thehorse.com, Managing Wet Hooves, cites a study conducted by Melinda Duer, MA, PhD, senior lecturer in chemistry at the University of Cambridge, who studies the effects of moisture on hoof walls.
In the study, Duer took the outer layer of hoof horn in the toe region from a normal Caspian horse’s hoof and ground it to a fine powder. The sample was examined and the nuclear magnetic resonance characteristics were recorded. The hoof powder was then dried out and examined again to compare differences between normal hoof wall, moist hoof wall, and dehydrated hoof wall.
Duer found that when the keratin in the hoof wall dried out, its chemical arrangement was altered. The keratin molecule chains comprising hoof tubules became less mobile and more rigid (the hoof wall becomes harder and stronger).
Yet her research also pointed out places in the keratin molecule where water can attach and break the hydrogen bonds that hold the hoof tubules together. When hoof horn absorbs water and swells, the normal keratin molecular structure is disrupted to accommodate the newly introduced water molecules. This causes the chemical and electrical bonds between adjoining keratin molecules to stretch and swell to let in the water molecules. The stretching causes the bonds to weaken, thus weakening the hoof structure and compromising the hoof’s shock-absorbing abilities.
Of course, environment is just one part of the equation. Genetics also plays a critical role. Some horses can stand in wet conditions for weeks without a problem. Others, like Freedom, who has “Thoroughbred feet” (i.e., he was not bred for his good feet), really suffers when he’s standing in mud all the time.
How do you dry out hooves?
- Keeping your horse inside and standing in a wood-based product (sawdust or shavings) helps, but only if your horse tolerates being stalled.
- Products like Keretex Hoof Hardener can be applied to the hoof to help dry it out. When the hoof moisture content is low enough (about 25%), you can use Keretex Hoof Gel to maintain the correct moisture balance.
- Instead of bathing your horse with a horse, sponge him off to keep his feet from being saturated with water.
Most experts seem to agree that hoof oils and gels for the most part do very little, but they probably can’t hurt.
As for Freedom? He was fine when I hunted him on Tuesday but was in obvious distress when I came to the barn on Wednesday afternoon. He had the classic signs of an abscess: he was reluctant to bear weight on his right hind, he was walking with his toe pointed down, and he was miserable! I actually think the bruising occurred during the Saturday hunt, which had a lot of rocks and roots — it just took several days to appear.
Thursday morning he was no better. In fact, he had a digital pulse in both hind feet and was shifting his weight from one to the other. Luckily my vet was able to stop by later in the day. Sure enough, he had a massive abscess in the right hind but it was very close to the surface and she was able to drain it without a problem. She thought the discomfort on the left was caused by his reluctance to put weight on his right. So, I packed both hooves with Magic Cushion slapped a hoof boot on both hinds, and gave him some bute.
Relief came quickly. By Friday he already looked more comfortable. Saturday he looked almost sound and Sunday I was able to take him for a walk. He was back in work on Monday, just a little bit too late for the last hunt.