When laminitis occurs, the hoof’s laminae — “fingers” of connective tissue that make up the white line and help hold the coffin bone in place — become intensely inflamed. If the damage is extensive, the attachments can become too weak to hold the coffin bone and it rotates out of position. It can even sink down closer to the sole.
Stages Of Laminitis
Early/prodromal stage. The horse isn’t yet lame. If you catch a horse at this stage of laminitis, the feet will feel abnormally cold. What’s going on is the trigger for the laminitis is causing the vessels within the foot to spasm. In experimental models of laminitis induced by carbohydrate overload or black-walnut toxicity, the severe decrease in blood flow lasts for a couple hours, followed by a return to near-normal temperatures.
Acute stage. At this point, somewhere between eight to 24 hours after the laminitis trigger, the horse will be lame. In experimental laminitis, this corresponds to the circulation through the hoof again dropping.
Basically, that initial two hours of reduced blood flow deprive the feet and hooves of sufficient oxygen and nutrients. Cell damage results. When the blood flow returns, the damaged tissues trigger an inflammatory reaction that again reduces blood flow to the foot.
Inflammation causes the pain. The inflammation again triggers increased blood flow to the foot — which now feels hot — with pulses in the digital arteries pounding. However, circulation to some areas, most notably the toe region, is still compromised.
Recovery. If the laminitis trigger is removed, inflammation normally subsides within 72 hours. Pockets of serum within the foot may make their way to the coronary band or sole to exit as sterile abscesses — abscesses not caused by bacteria — over the next 10 to 14 days, causing a period of increased pain until they drain. However, if the horse escaped extensive damage in the form of tearing of the laminae and displacement of the coffin bone, soundness usually can be expected within a few weeks.
If you suspect your horse is developing laminitis, don’t wait. The first hours are critical to reducing permanent damage and alleviating the intense pain your horse feels.
• Remove the trigger. Anything that could be the suspected trigger for the episode should be removed (see sidebar) and the veterinarian contacted immediately. The sooner you can reverse early circulatory problems or put the lid on inflammation, the better.
• Cool the feet. Cooling the feet is somewhat controversial, but we believe it’s a matter of common sense and should be instituted immediately.
• Administer ace and bute. Although the attending veterinarian should make the decision, acepromazine is generally the most reliable way to reverse vascular spasm and should be administered. Anti-inflammatory NSAIDs are indicated during the acute phase as well. Some veterinarians use intravenous or topical DMSO as well.
• Take X-rays. X-rays are indicated to determine if any rotation of the coffin bone has occurred and should be repeated any time there is a worsening or if the horse fails to improve as expected. Although you may sometimes hear otherwise, an acutely laminitic horse should not be forced to walk. The pain is nature’s way of telling the horse not to stress the damaged feet. Forced walking can worsen could damage.
• Call in an experienced farrier willing to work with your own veterinarian over the long term.
The time-honored approach for treating the acutely laminitic horse is to pull the shoes, lower excess heel, back up the toes to establish a more parallel position between the coffin bone and the hoof wall and keep the horse on a deep, soft surface. This is a physiologically sound trim. The goal is to remove mechanical forces that may put tension on the damaged and weakened laminae.
Note: There are a mind-boggling number of trim methods being touted by this expert or that for regular trimming, laminitis and other hoof ailments. We advise you to stick with the basics and discuss your options in depth with your veterinarian and farrier. This is not the time to go messing around with a new trimming theory. Your goal is to ensure the stability of the coffin bone and relieve the horse’s pain.
While there are a number of good pain-relieving hoof-support products in use for laminitic horses, we find simply fitting the feet with a layer of Styrofoam an excellent choice. It relieves pain and protects the hoof from further damage. Many horses properly fitted and maintained with Styrofoam “pads” don’t need pain-relieving drugs.
You can get precut Styrofoam blocks in a kit of four that can be trimmed for precise fit (sizes 00 to 4). They can be purchased from Equine Digit Support System, Inc. (EDSS Systems, www.edsshoofcare.com, 719-372-7463) for about $10.
If the horse still seems uncomfortable in the pads, remove them and ask the veterinarian or farrier to check the sole with a hoof tester. Sensitive areas, usually under the tip of the coffin bone, can be identified and the corresponding spots on the foam hollowed out.
Beyond the acute phase, successful rehabilitation strives to shift the landing and weightbearing to the back of the foot, where it belongs. The farrier will trim the hoof to achieve good alignment of the coffin bone with both the hoof wall and the ground surface. Areas of hoof wall where the white line is widened/stretched, or the hoof wall obviously separated, should be thinned so that further traction on the laminae does not occur when the foot contacts the ground and the hoof wall spreads outward. Good, regular farrier care is one of the most important and critical elements in your horse’s recovery.
Many horses are rehabilitated successfully barefoot, others have recovered with the help of specialized shoeing systems like heart bars or EDSS. The important thing to remember is that every laminitis case is different and what works for one horse might not work for another.
X-rays are important, so don’t close up your wallet if your veterinarian or farrier recommends them a couple of times during the rehabilitation. Your horse’s recovery is directly proportional to the skill and experience of the person applying the therapy, whether it’s shoes or a barefoot trim. If the horse is not improving, or even getting worse, with the current care, look elsewhere.
A horse whose feet have been damaged by laminitis should not be allowed to exercise heavily until the damaged portions of the hoof have grown out. As long as the horse is eating, drinking and passing manure and urine normally, don’t be concerned if he spends a lot of time lying down or isn’t up to trotting around. He’s just taking care of his feet.
Next month, we’ll discuss your options for long-term care of the chronically laminitic horse.