What’s this stuff on my horse’s hooves? Understanding the Periople

As a horse owner, you've likely noticed a soft, waxy substance on your horse's hooves, especially around the coronary band, where the hoof meets the skin. This substance is the periople, an often overlooked component of equine hoof anatomy. Knowing its function, and how changes in moisture content can affect it, can help you better understand the appearance of your horse’s hooves.

The periople is a thin layer that covers the upper part of the hoof wall, just below the coronary band. It is like the cuticle on human nails.

Just like our cuticle, the periople serves as the point of transition between the soft skin of the horse and the hard hoof wall. Its main role is to provide protection to the brand new hoof wall that is emerging from the coronary band. The portion of hoof wall requiring protection from the periople is actually very small extending only about 1/8th of an inch in length from the coronary band. This area is usually covered by the horse’s hair line.

This means that the perioplic material that can easily be seen everyday on your horse’s hoof has already served its purpose, and it is nothing but old excess production that is growing down with the hoof wall.

There is no “right” or “wrong” appearance when it comes to the periople.

Breed, climate, diet, work regimen, as well as hoofcare protocol on the part of both farrier and horse owner can all play a role in what the periople will look like on each individual horse.

Here are a two management scenarios that will cause the periople to have a different appearance on different horses:

1. A horse kept on pasture during a wet winter is likely to have a periople that looks like that of figure 1. In wet environments, the periople will absorb large amounts of moisture, which will cause it to gain a gummy consistency. Under these conditions, its color will also “whiten”, much like the dead skin on our fingers after we have spent a long time in the bathtub.

2. A performance horse kept in a stall with a sandy turnout during a dry summer may have a periople like that of figures 3 and 4. The horse in figure 3 has a farrier that dresses the bottom 1/3 of the hoof, which is considered the correct practice to remove flares while preserving the integrity of the hoof wall. This leaves much of the old perioplic growth intact. The owner of the horse in figure 4 wants the hooves to look polished when the horse is showing, so the farrier uses a sanding block to remove dirt and the old perioplic growth.

Much debate is out there on whether or not the layer of periople that remains on the hoof should be removed by farriers or horse owners for aesthetic reasons. After all, haven’t we said that the periople serves a protective function?

As previously stated, the portion of hoof wall that requires protection from the periople is actually quite small, so much so that for the most part, it is covered by the horse’s hairline.

The thick layer of perioplic material that can sometimes be seen on hooves is no longer essential, and removing it will cause no damage to the horse, or its hoof health. Many horses, depending on the type of soil they are kept and worked on, completely wear the old perioplic material off with physical activity anyway.

It is the soft periople that is serving as the immediate point of attachment between skin and hoof wall that we should take care not to irritate or damage.

As you can see in the picture above, not removing at least -some- of the old layers of periople from horses who do not naturally wear it off, can lead to the hooves acquiring an appearance that may be concerning to some.

The owner of the horse pictured thought some sort of fungus was growing on her horse’s hooves... nope! It’s just some old periople.

What does the periople on your horse look like? Have you ever noticed how its appearance can change seasonally? Next time you’re around horses, take a look at just how different and fascinating this structure of their feet can be!