Saturday, August 29, 2015

Can you tell which horse will get laminitis?


Maybe one of these horses will develop laminitis. Maybe all of them will. All horses are at risk for laminitis yet only a small percentage actually becomes lame from the disease.  (Aline Sagrebelny photo)

Can you tell which of the horses in the photo will get laminitis? You might think this is a trick question, and you’re right: it is. That’s because any of these horses might develop laminitis.

The point is: all horses are at risk for laminitis.

The Animal Health Foundation is 
interested in how the hormone insulin is
regulated and utlized in the horse.
We are funding extensive research
in Australia in this area and welcome
you to join us in supporting this
project. Your large and small donations
are welcome.
Here at Homestead Veterinary Hospital, where the Animal Health Foundation began, many horses have been nursed through laminitis. And when they arrived, there were very few similarities between them, other than they were all in severe pain. While it is true that horses who become lame with laminitis sometimes display physical signs of Equine Metabolic Syndrome (cresty neck, swollen sheath, irregular fat deposits) or Equine Cushing’s Disease (long, late-shedding hair coat, fat deposits over the eyes, muscle wasting), there are just as many horses that show no exaggerated outward signs. But these horses do tend to have elevated hormone levels.

Other horses develop laminitis after giving birth or undergoing colic surgery, eating too much grain, galloping on pavement, bearing weight unequally after an injury, or reacting badly to drugs or stress. So, no horse is ever 100 percent exempt from the risk of laminitis.

What can a horse owner do? Over the years, we have closely followed all the veterinary research related to laminitis prevention, and the Animal Health Foundation funded a fair share of it. Risk factors do exist, and some simple blood tests performed annually and evaluated by consistent laboratory standards will provide benchmarks to track changes in your horse's metabolism. This will help with the endocrine forms of laminitis, which are the most common types: Equine Metabolic Syndrome (insulin resistance) and PPID (Cushing's Disease) account for as many as 80 to 90 percent (1) of laminitis cases, depending on which studies you read.

The telltale signs of pre-existing laminitis, typically seen in horses with insulin resistance, can be seen in hoof tissue when it is trimmed. The white line is stretched and may be flecked with red, as seen quite vividly in the trimmings of this pony treated at the Homestead Veterinary Hospital. (Donald M. Walsh file photo)

With all types of laminitis, it is critical that horses be kept on a regular trimming or shoeing schedule with an informed farrier who knows the early warning signs of hoof problems and will keep you updated on any changes he or she sees in your horse's feet. This will give you a chance to get your vet involved sooner instead of later.

Your farrier should be watching for telltale signs of stretching in the white line or discoloration and bruising in the wall and sole and flecks of dried blood in the white line. Rings in the hoof wall are a common sign, but can be caused by other problems, as well.

Some early signs can be seen in how a horse handles turning, even in the barn aisle on the leadline. Watch for a horse that throws its head and uses its body to make the turn. Under saddle, a horse may suddenly resist lead changes, not want to canter at all, or throw its head and pins its ears when you come to the end of the long side of the ring. These behaviors may indicate many different types of lameness, but laminitis is certainly one to consider.

Notice how your horse stands, and watch for any changes of where he places his feet in relation to his body. You may see some changes as you are cleaning your horse's hooves. Pay attention when and if your horse starts to resist lifting one or more feet. Some horses with long pasterns will back their feet up under their front limbs so their pasterns look shorter and the knee wants to buckle forward; this is their way of relieving tension on the deep digital flexor tendon. These horses will lift one foot and then the other to relieve pain. They rock back and forth, but won't want you to pick up either one.

Dr. Walsh is the veterinarian
who started the Animal Health 
Foundation.
Other horses will stretch their pasterns so their weight is on their heels, and their feet will look like they are out in front of the leg. They look uncomfortable, as if they are nailed to the spot, and won't want to lift either foot.

With all of these signs, you may feel a strong pulse at the back of the pastern of one or both front feet and the hoof wall may feel warmer than normal. It won't hurt to soak your horse's feet in ice while you call your vet, describe the symptoms, make sure the person on the other end knows you are describing a possible emergency, and that you need immediate advice.

Laminitis can make us all feel challenged, but when we have the advantage of an early start and a good medical history, we have a much better chance of a successful outcome. You can help your horse avoid laminitis or catch it early if you know what to look for and what to do.

Thanks for supporting the Animal Health Foundation. Many of the little management tips we share with our clients and with audiences at lectures are the result of studies performed at Homestead Veterinary Hospital and by research funded by donors to the Animal Health Foundation. It all adds up to progress that will help your horses, and ours.

--Don Walsh, DVM
Animal Health Foundation

References:

(1) Karikoski NP, Horn I, McGowan TW, McGowan CM. The prevalence of endocrinopathic laminitis among horses presented for laminitis at a first-opinion/referral equine hospital. Domest Anim Endocrinol. 2011;41(3):111-117.