Sooner or later, just about every horse owner is going to have to deal with a hoof abscess. You’ll come to the barn to find the horse that looked fine when you last saw her is now lame — really lame. Fortunately, the pain normally rapidly abates once you can get the abscess to drain, and the hoof heals uneventfully — provided you have the equipment and knowledge to handle the situation like a professional horseman.
Any puncture wound to the foot that enters live tissue, including misplaced shoe nails, carries bacteria into the tissues and sets the stage for abscess formation. Letting the feet go too long between trims, especially when barefoot, leads to white-line stretching, and cracks can form that are then avenues for bacteria to enter. Prolonged exposure to wet conditions can soften the feet and make them expand more, which can also make the white-line connections weaken.
Horses recovering from laminitis are at particularly high risk. Infections can enter the foot through weakened laminar connections in the white line and often find collections of blood that are a perfect medium for growth. Laminitis can also result in the formation of “sterile abscesses,” collections of damaged tissue that trigger an inflammatory reaction. These dead tissues and pockets of inflammatory fluid will eventually exit the foot just like infections do. Keeping laminitic horses on anti-inflammatory medications for extended periods of time can actually prolong their pain by slowing the exiting of abscesses and fluid collections.
Finally, a horse that’s obviously sore a day or two after being trimmed may have unresolved abscesses. Trimming changes the mechanics of the foot, resulting in different forces being applied to walled-off abscess collections. This can cause abscesses to leak, causing pain and inflammation.
In the classic scenario, a horse with a hoof abscess will have a hot foot, pounding digital artery pulses at the back of the ankle, even swelling extending up the pastern or higher. However, it’s also possible for abscesses to be the problem when you have none of these external signs, even no reaction to hoof testers.
The one symptom that is always present and should make you think hoof abscess is pain. Hoof abscesses are one of the most painful problems a horse can have and more often than not they will completely refuse to bear weight on the foot, what is commonly called “broken-bone lame” or “three-legged lame.” If the horse is recovering from laminitis, the pain from an abscess is often worse than the original laminitis was.
A visit by the veterinarian and an X-ray to make sure the problem isn’t a broken bone or laminitis attack is usually warranted. Most abscesses don’t show up on X-rays, although they may if the organisms involved produce gas. In most cases, it will be a completely clean X-ray that clinches the diagnosis of hoof abscess.
Although there may be no response to hoof testers in some horses, they should always be used to attempt to find the site of the abscess. If a soft spot in the sole is found over a tender area, your vet or farrier may choose to remove a few layers of sole to help it drain easier. The frog clefts and frog itself should also be checked carefully to make sure no nail, piece of wood, etc. is embedded. Be sure to check under any flaps in the frog.
The coronary band and heel bulbs should also be checked carefully for any swellings, moisture or the appearance of small red dots. All of these can mean the abscess is trying to break through at the coronary band. Tapping along the hoof wall with a small hammer, and over nail heads, will sometimes help locate collections. Pockets of infection or dead tissue along the plane of the white line/laminae will exit at the coronary band.
What To Do
Get your farrier out to pull the shoe if shod, and trim the foot if needed. An unshod hoof is more free to expand, and a correct trim encourages good hoof mechanics. The combination results in more pumping action that encourages abscesses to exit.
After thoroughly examining and cleaning the foot, soak in water as hot as the horse will tolerate for a minimum of 20 to 30 minutes. If you have Epsom salts on hand, add 1 cup per gallon of water. Repeat soaks several times a day, or soak once a day but keep the foot poulticed between the soaking periods.
If you have been able to localize an area on the sole, heels or coronary band that looks like the spot where the abscess will exit, you can concentrate poulticing/drawing agents (see products chart) in that area. Otherwise, use generous amounts of poultice or drawing agents over the sole, coronary band and heel bulbs between the hoof soaks.
A cushioning, absorptive layer over this will improve comfort and protect the coronary band from pressure and irritation. Cover this with a corner cut off a heavy plastic bag or several layers of heavy plastic wrap. To hold everything in place, you can boot the horse or wrap over top of the plastic with duct tape. A wrap of self-adhesive bandage, like Vetrap, between the plastic and duct tape helps secure the assembly and makes it easier to get the duct tape or boot in place without causing your padding to shift.
Continue soaking and poulticing/wrapping until the horse is sound and there’s no evidence of drainage on the poultice and bandages for at least 24 hours after the horse graduates to turn out.
Unless the lower leg is severely swollen and your vet decided that antibiotics are needed, avoid antibiotic use. Antibiotics can slow the exiting of abscesses.
Avoid using any high doses of anti-inflammatories, which can also slow exiting. However, there’s some advantage to reasonable doses in horses that refuse to move around or put any weight on the foot, because movement and weight-bearing will help mobilize the abscess collections.
Definitely discuss this issue with your vet, but a reasonable game plan in most cases is to avoid these drugs for a day or two to see if you can get the abscess to exit with soaking and bandaging. It’s difficult to see the horse in pain, but warm soaks are soothing and masking the pain doesn’t do anything to resolve the problem, especially if you are fooled into thinking the horse is “better” when the pain is masked and you’re less aggressive about soaking as a result.
Although it sounds counter-intuitive, for horses that are extremely painful and don’t tolerate warm soaking well, we’ve had success in encouraging drainage using cold soaks. The water still softens the tissues, and the pain relief they obtain from cold lasts several hours and encourages more movement.
While the horse is still lame, confine her to a stall or small paddock where she has hay and water within easy reach and will not be bothered by other horses or have to compete with them for food and water. Once the abscess has started to drain and pain is eased, turnout in a paddock where she can move around more will help make sure it drains completely.
During healing, open areas need to be covered and protected.