Heel cracks (a deep opening in the sulcus between the heel bulbs) are the primary reason our horses suffer from recurring thrush. Heel cracks are created by thrush and bacterial infection and are, in fact, an open wound leading directly into the inner tissue of the foot. They are a warning sign and they should not exist.
The tissue between a horse’s heel bulbs is soft and pliable, allowing the thrush bacterium to burrow in and create a breeding ground. Thrush bacteria are anaerobic, meaning they must avoid oxygen to survive.
Imagine you have a pile of fresh-cut grass clippings. If you leave the clippings in the sun for a few days, the warm air and sunshine will dry them up and soon they will blow away. But what happens if you put those same clippings into a shallow hole and cover them with a piece of cardboard? In a few days you will discover that the grass has become a congealed rancid mess. This occurs because we have given bacteria the three things they need: moisture, low oxygen and food.
The same thing occurs inside the heel crack. The interior of the cracks are warm and moist, the perfect hiding place and breeding ground.
It is important to note that bacteria can also gain access through the collateral grooves. Take a look at your horse’s foot. If you see the groove disappear inward, undercutting the frog, this is another warning sign. The bacteria can slip inside that crack and eat its way toward the heel. Additionally, whenever thrush bacteria are active inside the foot, the infected tissue becomes soft. It is now possible to accidentally dig into live tissue when performing our normal daily hoof cleaning. This, of course, creates abnormally deep collateral grooves, which aids the bacterial entry.
Add a little moisture from a rainy day, a water trough mud puddle, or even a wet spot in the stall and the bacteria are ready to wreak havoc. We have now officially entered the endless cycle of thrush.
Most of us think of thrush as the “Black Goo.” The truth is the black goo is the result of thrush. It is the deteriorated tissue created after the bacteria have eaten healthy tissue. This is why thrush smells so terrible.
TREAT AND AID REGROWTH
The first step in treating heel cracks is to get rid of the active bacteria that have caused the infection. It is vital to choose a non-caustic product that will not burn the tissue. Some owners use bleach, peroxide, gasoline (believe it or not) as well as many caustic over-the-counter products. By using these items we will indeed kill bacteria, but we will also damage healthy tissue. This will inhibit any kind of post-treatment healing. In normal circumstances this active thrush treatment will take about a week.
Once we are comfortable that the bacteria and damp breeding grounds are eliminated, it is time to focus on the heel crack and deep collateral groove regrowth. All these cracks should be treated with a non-caustic, bacteria-fighting product several times a week. The goal is to prevent any new bacteria from entering the foot. This allows the tissue to regenerate, and it will soon begin to grow out naturally. Depending on the depth of the cracks and the overall health of the horse, this process normally takes 20-40 days.
Beware: Thrush is not “curable.” Once a horse has thrush, he is susceptible forever. If I send my horse out into the pasture with his newly regrown heel crack, thrush will soon be back. To prevent this we must become pro-active. It is good practice to continue using a non-caustic bacteria-fighting product on a regular basis (3-4 times per month). Apply on the heel, in the collateral grooves, and along the exposed white line areas, as these areas are the prime access points for bacteria and fungus. Additional preventive measures include keeping the stabling environment clean and dry, daily hoof cleaning, good exercise, proper diet, and very close observation.
DO HEEL CRACKS AFFECT ANATOMY?
Yes, heel cracks are warning signs for thrush, but it’s important to consider other ramifications. The heel bulbs are intended by nature to be a unified pad. With each step this pad receives the brunt of the horse’s weight. But when a heel crack is present, the bulbs split apart, affecting stability.
Consider what happens to forward momentum. Instead of the energy flowing from the unified heel straight up into the shoulder, it is now splitting into two separate energy paths. These paths must now awkwardly work their way upward, often causing soft tissue damage. Since the energy is diffused, so too are explosive power, strength, speed, maneuverability, agility, and stamina.
If we include the pain and tenderness caused by thrush, this horse is now significantly compromised under any circumstance. Simply stated: A horse with a heel crack is incapable of 100% performance.
Heath Kizzier is Vice President of NO THRUSH – Dry, Thousand Oaks, CA. To contact the author, email: HeathKizzier@NoThrushShop.com or call 805-813-6257.
PHOTO CREDIT: Heath Kizzier, NoThrushShop.com