WINTER LAMINITIS

It’s a phrase that would send a chill down most horse owners’ backs. But, what exactly is it?

BY ALEESHA HARRIS

“Winter laminitis is not a disease in itself. Cold alone has not been linked to laminitis,” Dr. Marielle St. Laurent, of Paton Martin Veterinary Services in Langley, BC, explains. “However, there are some reasons why horses could get laminitis specifically in the winter months.”

Dr. St. Laurent points to the shift from softer foundations during the warmer months to the hard, frozen ground of the winter season as a key contributor to increased soreness in horses. A common term in horse health, “road founder,” which refers to the onset of laminitis linked to hard concussions to the hooves, can further be utilized in order to understand the term.

Essentially, “winter laminitis” refers to the onset of road founder, but from climate-related ground hardness rather than poor footing alone.

“Constantly being on hard frozen ground could contribute to this disease,” Dr. St. Laurent says. “Not working on hard ground constantly is also imperative.”

Laminitis is a disease that causes foot pain in horses. It usually presents as a horse taking short strides and having trouble turning, Dr. St. Laurent explains. Acute signs, occurring within the first 72 hours, also can include hot feet, increased digital pulses and — when severe — refusal to walk. Severely affected horses will often lean back in order to put weight on their heels in an attempt to relieve the pressure on the front of the hooves.

“When it’s more chronic, usually we will notice an abnormal hoof capsule shape, often with horizontal lines or a dished appearance,” Dr. St. Laurent says. “They typically have very flat feet and farriers will notice abnormalities in the white line.”

By the time a farrier sees abnormalities though, the problem has been occurring for quite some time.

“Laminitis is often viewed as this very severe very painful disease, but that isn’t always the case. People are often surprised when they are told that their horse has or had an episode of laminitis and they haven’t noticed a problem themselves,” Dr. St. Laurent says. “Horses can have subtle or mild laminitis episodes. Some of them go unnoticed by owners because they are not severe and only last a day or two.

“If owners recognize mild episodes, they can test to try and determine what is triggering it and hopefully prevent more severe episodes in the future.”

As with many equine ailments, preexisting health conditions can contribute to the onset of the disease. Laminitis, Dr. St. Laurent says, can affect all breeds, from Miniatures to Drafts.

“The main predisposing factors are insulin resistance and Cushing’s disease,” Dr. St. Laurent says. “Any very sick horse with what we call toxemia is also predisposed to it.”

Certain medications, such as steroids, have also been linked to laminitis, according to the veterinarian. However, it is believed that in many of these cases, the horses had a predisposed underlying factor, as well.

“For example, a horse had mild Cushing’s disease that was not causing laminitis on its own but coupled with steroid treatment it might trigger a laminitic episode,” Dr. St. Laurent explains.

For horses where insulin resistance is a factor, there can be additional concerns linked to cold weather and the onset of laminitis.

“Frozen grass also has a high sugar content, and this can trigger laminitis in horses that are insulin resistant,” Dr. St. Laurent says.

A horse’s overall body weight and body condition can play a major role in the potential for developing laminitis.

“Most insulin resistant horses that I see are severely overweight,” Dr. St. Laurent says, adding that some skinny horses can also be insulin resistant.

With weight appearing to play an important role in the development of the condition, Dr. St. Laurent says prevention is an important way to avoid any laminitic incidents.

“All horses should maintain an appropriate body condition score and avoid being overweight,” she says. “Regular exercise also helps to maintain not only an appropriate weight, but is also believed to be helpful in regulating blood sugars and insulin.”

Tests can be done to see whether a horse is in fact, insulin resistant. Horses in their late teens and older can also be tested for Cushing’s Disease in order to make a diagnosis before an onset of clinical signs occurs, Dr. St. Laurent says.

Because, when it comes to laminitis, early detection is essential.

“Severe cases where there is severe rotation of the coffin bone are less likely to recover,” Dr. St. Laurent says. “If we can treat horses before that happens, we have a much better chance at keeping them sound and happy.” WHR

ABOVE: When laminitis occurs to the point of coffin bone rotation, the hoof wall separates from the plantar cushion and can cause separation of the white line – or a condition known as “seedy toe.” The hoof in this picture has additionally experienced sole abscesses, also caused by the rotation. BELOW: Horses can have subtle or mild laminitis episodes. Some of them go unnoticed by owners because they are not severe and only last a day or two. By the time a farrier sees abnormalities though, the problem has been occurring for quite some time.