One of the most complex diseases that affects horses — laminitis — is caused by a number of triggers and causes pain, sometimes extreme pain, in a horse’s feet. The outcome of laminitis ranges widely, from death or limited mobility to minimal discomfort and considerable length of life.
One of the specialists in this disease is Scott Morrison, DVM, who is in the podiatry department at Rood & Riddle Equine Hospital. Morrison said he sees three levels of chronic laminitis, and graded worst to least, they are chronic unstable, chronic stable, and chronic low-grade.
The worst level is loads of trouble. It requires “special shoeing because the foot doesn’t grow sole and walls properly, and you need a specialist,” Morrison assessed. This is understandably the most deadly situation for a horse that is being managed.
In contrast, the stable version of laminitis presents problems, but it can be managed. Morrison said that this level of laminitic involvement is characterized by wide growth rings at the heel and narrow ones at the toe because of “uneven growth of the hoof, and there will typically be a stretched white line at the toe, as well.”
The low-grade laminitis is “common in mares, but sound management can keep them comfortable and stable” without as much intervention as the two higher-level sorts of laminitis.
Given the relative complexity of the disease and relative frequency that we see it, Morrison offered some things to look for in evaluating our own horses or in assessing horses at the sales.
He said, “First of all, I’d pick up and look at the bottom of the foot. The white line should be nice and tight. If it’s stretched, that could be a warning sign. I’d look at the growth rings on the hoof wall. At the sales, these are sometimes buffed off, but if a hoof wall was rasped down pretty hard or had another color showing through, I’d take a close look at it.
“I look at the contour of the hoof wall. Is it dished coming out to the toe? If I’ve seen that or a stretched white line, I wouldn’t hesitate to check the pulse in the hoof. And if I’m not reassured, I would take radiographs.”
Radiographs will show whether there is internal damage to the hoof. Rotation of the coffin bone is one of the clinical signs of laminitis, not foot soreness, which can occur for many reasons. Rotation, or even worse, sinking of the coffin bone is a source of great concern.
Horses with low-grade laminitis may have a slight degree of rotation, but the really bad occurrences of laminitis result in significant rotation and sinking.
Even among horses with horrific laminitis, such as sloughing of the hooves, there are some miraculous survivors, but Morrison said that “body type is a factor in that, too. The lighter horses will have a somewhat better prognosis for recovering” from even the worst-case situations with laminitis.
On the other hand, heavier horses have more problems. Morrison counseled that one of the additional physical traits to watch for in potentially laminitic animals is a heavy body, a cresty neck, especially in a mare, and fatty deposits on the body.
The reasons for concern about body type include the obvious pressure that a heavier horse puts on its feet, but also insulin resistance is one of the factors known to cause or predispose a horse to developing laminitis. And heavy-bodied easy-keepers are commonly found to have insulin resistance or equine metabolic disorder.
Other factors known to play a role in triggering this disease include stress, colitis, spring grass or other rich feed, and leg-support laminitis (such as befell Barbaro). Just from this list, a wide variety of things can precipitate laminitis, but all of these factors share the common traits of stressing the horse and creating inflammation.
Anti-inflammatories, such as bute, are among the medications used to combat laminitis. Morrison noted that “there are a range of exciting new treatments for laminitis, including stem-cell treatments, sole supports, and special shoes that help to stimulate blood flow while supporting the horse.”
The bad news is that laminitis is with us and will continue to be because it’s not caused by a pathogen like most diseases. It’s caused by multiple factors.
The good news is that research and development are making survival more likely for horses with laminitis and raising the quality of life for them.
*The preceding post was first published at Paulick Report earlier this week.