By now, the basic facts of laminitis are as familiar as they are frightening: Brought on by mechanical or metabolic stress, this devastating inflammation of the soft laminae of the hoof can quickly spiral out of control, taking a horse from perfectly sound to immobilized with pain within 12 hours.
As laminitis progresses, the laminae may weaken, stretch and fail, detaching from the hoof wall and allowing the coffin bone to rotate downward toward the sole. This, in turn, may lead to the permanent de-formity of the hoof known as founder. If a horse recovers, his soundness may be compromised for life. In many cases, euthanasia is the only humane solution.
Fortunately, researchers have made great strides in understanding laminitis and its causes. So rather than simply worrying about your horse's prospects for developing the condition, you can assess his risk and take steps to mitigate it.
To help you, we've assembled a brief risk-assessment survey, composed of "yes" or "no" questions. The more "yes" answers you end up with, the greater your horse's risk of pasture-related laminitis--brought on by the ingestion of starches and sugars found in grasses--which accounts for 70 percent of all cases.
Of course, there's no way to prevent every case of laminitis. But with careful management, you can reduce any horse's likelihood of developing the condition. Answer the following questions to determine your horse's risk, then use what you've learned to develop a targeted prevention program.
1. Has your horse had laminitis before?
The answer to this question is the single greatest predictor of a horse's susceptibility, for several reasons:
- After recovery from laminitis, the internal structures of a horse's foot may be more vulnerable to the condition in the future.
- Any horse who has had laminitis has at least one significant risk factor, even if it hasn't been precisely identified.
- Many cases of "recurrent" laminitis are simply flare-ups of an ongoing condition: Although the horse improves or learns to compensate enough to appear sound, the underlying mechanisms of inflammation never truly subside and any new insult causes it to worsen.
If your horse has had laminitis, ask your veterinarian to make sure the situation has been resolved and then investigate why it may have happened. This will most likely require blood tests and a review of your horse's lifestyle and work schedule. In some cases, however, the cause is never found.
2. Does he come from a bloodline prone to laminitis?
Laminitis occurs more frequently in horses of certain breeds and from specific families. The reasons for these tendencies are not fully understood, but research suggests that in some horses a "thrifty" gene may be responsible. This gene, or collection of genes, allows a horse to survive drought and other deprivation but sets him up for metabolic stress--and laminitis--when nutrient-rich food is plentiful. So far, research to identify these inherited tendencies has focused on Welsh and Dartmoor ponies, but experts believe that the phenomenon probably exists in other breeds as well. If several of your horse's relatives have had laminitis, assume his risk of developing the condition is high, too.
3. Does your horse's diet include a high proportion of grain?
Most grain- and concentrate-based diets are high in the plant sugars and starches known as nonstructural carbohydrates (NSC). All of these except fructan (which we'll discuss later) are primarily digested in the horse's stomach. When a horse consumes more NSCs than his stomach can handle, they spill over into the hindgut--the cecum and large intestine--where the sugars begin to ferment, creating an acidic environment that causes a die-off of microflora. This, in turn, leads to imbalances that can trigger colic as well as laminitis.
The typical "grain binge" laminitis seen in feed-room raiders is caused by this hindgut imbalance, but it also can happen without massive overindulgence. In fact, two or three extra pounds of grain can trigger the disastrous chain of events in some horses.
Hay, on the other hand, is high in structural carbohydrates, which make up the cell walls of plants. These are readily digested in the hindgut and do not alter the acidity of the digestive tract. The safest diet for a laminitis-prone horse, then, will consist primarily of hay with only as many concentrates as are required to meet energy needs.
4. Does your horse have access to lush or improved pastures?
Although good-quality pasture is a cornerstone of equine nutrition, grazing rich pasture plants can increase the laminitis risk of horses with metabolic issues. Lush pastures contain higher levels of sugars, which can overwhelm the digestive system of vulnerable horses.
