Thrush and Advice for the Hoof-sore

Q: What is the relationship between chronic, severe thrush and my horse's contracted heels?

A: Thrush and contracted heels often go hand-in-hand...but by the time a veterinarian or farrier is called to help the horse, it is hard to tell which came first, particularly because so much "ordinary" thrush goes untreated. Some owners think horses' feet always smell that way!

Hoofcare & Lameness

Preparing a young event horse for glue-on shoes at New Bolton Center.

Thrush seems to be a worsening problem, particularly cases of what we call "deep sulcus" thrush. The sulcus is usually not deep at all; when thrush gets in that area and "eats" away tissue, the horse's natural mechanism for keeping the heels in their normal position is distorted, and sheared or contracted heels are a common result.

An interesting thing to do is look at a model of a dissected foot; look at the heels, sensitive (inner) frog, and digital cushion. Several researchers are studying the digital cushion's ability to remodel itself, and at what point its fatty content changes and it can no longer return to its normal shape, causing a permanent, irreversible change in hoof conformation.

Often (in the simplest cases), contracted heels are caused by leaving the horse improperly shod for a long time, or repeatedly shoeing the horse with too-small or constricting shoes, i.e., nailing the shoes behind the widest part of the foot. (Just because the shoe manufacturer punched nails there doesn't mean that you have to use them!)

In the United States, a leading shoe manufacturer is funding a study to determine the following:

  1. How many farriers actually do nail behind the widest part of the foot, and
  2. What the effects of nailing back there have on the deformation of the foot. Many farriers "nail back" because they believe nailing back helps secure the shoe on the foot; therefore, it is a difficult practice to break. Most farriers (around here, at least) will only nail back on the outside or inside, depending on the horse's hind foot flight; it is quite common here to see horses with seven nails.

Another cause of contracted heels is uneven weight-bearing in the foot. The list of usual suspects includes sidebones, ringbone, and overly straight pasterns.

Creative shoe designs probably won't help this horse recover any more quickly than simply leaving it unshod and turning it out in a good, clean pasture for some recovery time. Supplementation with a "Farriers Formula" type biotin/methionine product might be beneficial to promote new growth.

Nothing will help this horse if the daily caregivers aren't involved and know why the problem happened, and how it can be prevented from recurring. (For more information see related article on Thrush on page 39.)

Q: My horse's hooves do not grow. They are crumbly and flake off. I have added a supplement to the diet, and I am painting the hooves with pine tar. This condition has persisted, and I cannot ride. Can you direct me to information that might help her? Do you have any ideas?

A: Here are some suggestions for you:

1. Check that the supplement is of good quality, which might be expensive. Hoof really grows from the inside out; a healthy inner horse grows a good foot. How's your hay? Watch for new growth at the coronet, not at the ground surface!

2. What does the farrier say? What does the veterinarian say? Have you changed anything in the horse's diet, pasture, or exercise lately?

3. Is the horse shod? Even though the feet are not growing, they need to be trimmed every six weeks or so. Horses need regular manicures, no matter how much the feet seem not to grow or if the horse is barefoot.

4. Glue-on shoes are an option. Also, EZ boots can help, particularly if the horse is turned out and stamping at flies all the time. Do not leave them on for more than a few hours at a time.

5. A hoof care product that will protect the hoof from repeated drying and soaking could help.

6. Do not ride the horse until you are sure it is sound and healthy. The weight of a rider might be harmful, as could hard surfaces. Consider hand-walking, aquatic treadmills, and especially swimming for exercise, if good turnout isn't available.

Q: We have a Shire with a long-standing problem in his front inside hoof. From radiographs, our veterinarian has discovered that he has a crack on the inside and the shoeing nail gives him great pain. We thought about using shoes which do not need nails. Do these exist? Can you suggest some help?

A: The most important thing you can do for your horse is to ascertain why the crack developed and remove that problem; otherwise, the crack will never heal. That begins with a balanced trimming. Then follow instructions for helping any-sized horse with a quarter crack.

The condition you describe sounds like a "blind quarter crack," which is invisible from the outside but will eventually "pop" through if the pressure is not removed.

The shoe should be a broad, flat, full-heeled shoe that will support the whole foot. The offending nail position can be avoided by simply punching a nail hole in a new place on the shoe or drawing a clip in that part of the shoe instead of through the crack. Sometimes the area of the crack is "floated" (trimmed shorter) above the shoe, or the shoe is "seated out" to avoid weight-bearing in that area.

Glue-on shoes would have to be custom-made for a Shire, but you could work with the Glu-Strider company on some ideas for glueing on just that part of the shoe.

Make sure your horse isn't forging or over-striding, particularly if pulling a load. Check the shoes all the time to make sure nothing is twisted or loose if you are using the horse in the woods, in the snow, or in a hitch.

Q: I bought a Quarter Horse gelding in June. He is my first horse. He has thrush. When we bought him, I started treating his hooves with a thrush product. I didn't notice any difference, so I quit applying it. I was told that just being in a dry paddock would help, as would keeping his feet cleaned out. Every time I rode him, I cleaned out his feet -- about every day. Then he threw a shoe. The owner told us that his shoes had been reset right before we bought him. So, I figured I had another six weeks. Now his back feet seem okay. How can I tell when the thrush is all gone? When I pick up his left hind hoof, it is pink colored on the bottom. Is there any reason for this?

A: You need to have a horse-specialist veterinarian out to look at the horse. Have him or her go over the horse with you and write down what he/she says. Have the veterinarian do an overall checkup on the horse and in particular check the horse's vaccinations and worming schedules, teeth, and feet. Tell the veterinarian ahead of time about the pink area on the sole of that hind foot. This is important, in case radiographs need to be taken. Do you have health records from the former owner?

Show the veterinarian the horse's stall and pasture. If your pasture is too wet, or the horse always stands by a gate or under one tree, you can put down straw, gravel, or shavings to absorb the moisture in that area. You also might need to confine the horse where it can stay dry.

It is not enough to just pick out the feet of a thrushy horse; you need to get a brush--like a human's nail brush--and scrub the sides of the frog and in the groove (sulcus) between the bulbs of the heel. Did you follow the manufacturer's directions to help the thrush? Medicating a dirty foot is futile.

Horses throw shoes all the time. There is no rule that says that shoes have to stay on six weeks--or six days. It is better to throw a shoe than to have a too-tight shoe hurt his foot. And mud doesn't help!

You are doing the right thing to get help for your horse. Keep learning, and do the right thing so you can have fun with your horse--for a long time to come!

About the Author

Fran Jurga

Fran Jurga is the publisher of Hoofcare & Lameness, The Journal of Equine Foot Science, based in Gloucester, Mass., and Hoofcare Online, an electronic newsletter accessible at Her work also includes promoting lameness-related research and information for practical use by farriers, veterinarians, and horse owners. Jurga authored Understanding The Equine Foot, published by Eclipse Press and available at or by calling 800/582-5604.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More