Laminitis is probably one of the most dreaded diagnoses in the horse world. Dysfunction and/or inflammation of the tissue (laminae) that connects the coffin bone to the inside of the hoof wall, laminitis can cause excruciating pain and permanent unsoundness. In many cases, euthanasia is the most humane option.
Treatment options for laminitis remain limited. Icing the feet can help to curb the inflammation in the tissues, but once the horse begins showing outward signs of pain, the damage is already underway. At that point, supportive footing---such as deep bedding or various hoof pads or shoes---and anti-inflammatory medications may help halt or slow the damage to the hooves, but they cannot reverse it.
It’s far better to stop laminitis from developing in the first place. In recent years, researchers have made great strides in identifying the factors that cause laminitis. And while not every case can be avoided, it is now possible to greatly reduce the risks that any horse will develop this disease. Here are five basic steps you can take to protect your horse from developing laminitis:
IDENTIFY AND CONTROL UNDERLYING METABOLIC DISORDERS
One surprising statistic researchers have uncovered in recent years is that about 70 percent of laminitis cases develop as a result of metabolic disorders. This form of the disease---called either pasture-associated or endocrinopathic laminitis---results from hormonal imbalances. Endocrinopathic laminitis tends to cause a low-grade chronic form of the disease that comes on slowly and causes vague soreness rather than extreme, sudden pain. Failure of the laminae and subsequent displacement of the coffin bone, if it happens at all, is slow and gradual rather than sudden and catastrophic.
The good news is that the two major metabolic disorders associated with laminitis can be diagnosed and controlled well before the horse develops any signs of serious footsoreness. Talk to your veterinarian if you are concerned your horse may be at risk for either of these conditions:
• Equine metabolic syndrome (EMS) is an endocrine disorder characterized by insulin resistance, a condition similar to type 2 diabetes that leads to abnormally high levels of insulin in the blood. Affected horses are likely to be easy keepers who gain weight easily. They are also likely to be either obese or to have abnormal fat deposits along the crest of the neck, over the tailhead, behind the shoulder or in the groin area. These horses may have had previous episodes of very mild laminitis that left distinctive growth rings on the hoof wall. EMS tends to develop in younger horses, and it can be controlled by managing diet and exercise.
• Pituitary pars intermedia dysfunction (PPID), also called equine Cushing’s disease, is caused when the pituitary gland malfunctions and releases abnormally high levels of hormones, which sparks a cascade of other imbalances that can affect systems throughout the body. In addition to a propensity to laminitis, major signs of the disease include a long, heavy coat that is slow to shed out, increased thirst and urination, excessive sweating, loss of muscle mass, lethargy, and an increased susceptibility to infections.
PPID is more likely to develop in horses over the age of 15 or so, but it can appear in those as young as 7. The disease can be kept under control with the drug Prascend, which contains the active ingredient pergolide.
MANAGE YOUR AT-RISK HORSE’S DIET CAREFULLY
For horses with metabolic disorders, dietary management is crucial to preventing laminitis. Even small or “normal” portions of sugars or simple starches found in grains and lush grasses can trigger an episode. If your horse is diagnosed with EMS or PPID, you may need to take these actions:
• Limit or eliminate sugars and starches. Most horses can do just fine on grass hays with no added concentrates. If yours needs more calories to maintain his body condition, look for a feed that derives calories from fat rather than starches. Breaking up his ration into multiple small meals served throughout the day can also help prevent spikes and wide fluctuations in the levels of insulin and glucose in your horse’s bloodstream. You’ll also need to be vigilant about reading labels when choosing supplements, treats, ration balancers and other additions to your horse’s diet---many products contain molasses and other sugary or starchy ingredients.
• Soak hays prior to feeding. Even grass hays can have high levels of sugars and simple starches, also called nonstructural carbohydrates (NSCs). However, these NSCs are water soluble---soaking hay in water for up to an hour prior to feeding can reduce concentrations of these nutrients by as much as 40 percent.
Not all hays will require soaking. The most effective way to determine the levels of NSCs in your hay is to send off a sample for analysis, both before and after soaking. Your veterinarian or a veterinary nutritionist can make specific soaking and feeding recommendations for you based on laboratory results, but generally the goal is to limit NSC levels to 10 to 12 percent for horses with endocrine disorders.
If you do soak your hay, always feed the wet portion immediately, before mold can grow. Also, avoid soaking your hay for longer than the suggested time frame. Prolonged soaking may remove too many water-soluble vitamins, minerals and other nutrients your horse needs to thrive.
• Reduce access to lush pasture. Lush pasture grasses are rich in sugars that can cause laminitis in at-risk horses. Sugar levels of pasture grasses tend to fluctuate throughout the year, with peaks in the spring and fall. Sending grass samples off for laboratory analysis is the best way to be certain of the nutrient levels in your pastures. Your veterinarian can help you interpret the results and make turnout recommendations based on your horse’s individual needs.
Some horses may need to wear grazing muzzles or be kept off of pasture only at certain times of the year. Others might need to have their grazing restricted throughout the season. For those who are especially vulnerable to laminitis, the only safe form of turnout may be in a dry lot year-round (although efforts need to be made to provide them with exercise).
• Control obesity. If your at-risk horse is overweight, taking off the extra pounds will both improve his insulin sensitivity and reduce his susceptibility to laminitis. Reducing the sugars in a horse’s diet will help with weight control, but you’ll also want to talk to your veterinarian about a safe exercise regimen, especially if your horse is older or arthritic or has already experienced bouts of laminitis.
AVOID DIETARY EXTREMES
Even a normal horse is vulnerable to laminitis under certain conditions. Another well-documented form of laminitis is associated with systemic inflammation, caused when bacteria and/or their toxins get into the bloodstream and spread throughout the horse’s body. This form of laminitis is often acute, sudden and excruciatingly painful; separation and displacement of the coffin bone is common and usually catastrophic.
Systemic inflammation can develop after a localized infection in any organ, but it often begins in the intestine after acute digestive distress. The best known triggers for gastrointestinal laminitis can be avoided:
• Avoid starch overloads. When any horse eats more starch or sugars all at once than he can digest in his stomach, the excess nutrients pass into the intestine and hindgut, where they ferment and produce byproducts that trigger inflammation in the gut wall and ultimately can lead to laminitis. This can happen in the classic “breaking into the feed bin” scenario, but horses who are fed large grain meals to keep up their weight are also vulnerable.
Horses who require large amounts of concentrates must be fed carefully. One option is to break up the large meals into smaller portions fed throughout the day, so the horse never needs to digest too much at once. Feeding hay first may also slow down the horse’s consumption of grain and help to keep the starches in his stomach longer. Alternatively, if your horse needs a high-energy feed, look for one that provides more calories from fat than from starches.
• Make dietary changes gradually. A horse’s intestinal flora---the “good” bacteria that reside in the gut and aid digestion as well as other functions---live in a balanced population that are adapted to the foods that he eats. When a horse’s diet changes abruptly, large portions of the flora may die off at once, potentially releasing toxins that may ultimately trigger laminitis.
To prevent this, introduce any changes to the horse’s feed gradually. If switching to a new type of concentrate, for example, substitute only a small amount for the horse’s old feed at first, then gradually increase the proportion of the new feed with each subsequent meal over the course of at least a week.
WATCH FOR LAMINITIS WHEN TREATING OTHER ILLNESSES
Systemic inflammation that leads to acute laminitis can originate in other organs as well as the intestines. More common examples include a mare who retains placental membranes in her uterus after giving birth or a horse with severe pleuropneumonia, an infection in the lungs. But just about any internal organ can be the source of the infection. Severe gastrointestinal illnesses, such as Potomac horse fever or enteritis, can also lead to laminitis.
Any horse who is this gravely ill will already be under a veterinarian’s care, and if you’re caring for him at home, she will likely coach you on how to watch for the earliest hints of laminitis. For example, she’ll show you how to check your horse’s digital pulse on the back of the fetlock and feel for heat in the hoof wall. A “bounding” pulse is a sign of pain and inflammation in the foot.
Icing the horse’s feet as a preventive measure may be advisable. Buckets of ice water are the old standby, but you’ll also find a number of boots and other products designed to keep a horse’s hooves cold. Keep the cold therapy going continuously until a veterinarian can see the horse and guide further treatment.
KEEP UP THE BASIC HOOF CARE
Unusual physical stresses on a horse’s hooves can strain the laminae and cause separation from the hoof wall even in the absence of inflammation or hormonal causes of the disease. These forms of laminitis are relatively rare and can’t always be prevented. But if your horse is at risk in any of these scenarios, you can take steps to reduce the chances of serious trouble:
• Take care of the “good” hoof. A horse with a serious leg injury must bear a disproportionate amount of his weight on the opposite side, and the pressure can sometimes lead to laminitis in his “good” leg. Why this happens isn’t fully understood, but if you are caring for an injured horse, your veterinarian will instruct you on how to protect the uninjured leg, possibly with wraps or Styrofoam supports. You’ll want to remain alert to put the leg on ice at the earliest signs of heat or pain.
• Keep up with regular trims. The long-toe, low-heel shape of overgrown hooves increases the downward pull of the coffin bone and strains the laminae to the point where even a minor amount of inflammation might lead to a catastrophic detachment. Maintaining a regular schedule with your farrier will help keep your horse’s feet well balanced and strong.
• Choose good footing. Extremes in footing can be hard on a horse: Wading through ground that’s too soft stresses the muscles and soft tissues and increases strains on the laminae, while fast work on hard surfaces increases concussion in the foot. Neither is likely to cause serious problems for a normal horse, but one who is already experiencing low-grade laminitis may be vulnerable to a more catastrophic failure after working in less-than-perfect footing conditions. When riding, choose trails that are neither too hard nor too soft, and stick to a walk when you must cross pavement or rocky terrain. If the ground in your turnout paddock is too hard, consider adding sand, gravel or another footing product that will provide some cushioning.
This article first appeared in EQUUS issue #463, April 2016.