by Dr. Don Walsh, DVM and Kathryn Watts

This is the third of a three part series on Laminitis. You can view Part 1 at: http://www.equestmagazine.com/v3s6/article21-06-a2.php.

effort to learn as much as possible, and are 'battle ready' and armed with the most sophisticated defensive weapons when laminitis attacks. Ask your professional caregiver if they are comfortable taking on your case. Let them know if you are willing and able to treat aggressively and seek out the best, up to date, expert care available. They may choose to refer you to a specialist who is more interested and experienced in treatment of laminitis.

Use of Pain medication

Routine use of medications such as bute (phenylbutazone) or banamine to relieve pain is controversial. Pain medication does not stop laminitis; it only masks the symptoms. While pain causes stress to both the horse and the owner, it is important to acknowledge that pain has an important function. It prevents a horse with laminitis from moving around too much during a period when its feet are in jeopardy, causing rotation of the coffin bone. Pain is not the enemy - gravity is the enemy. The best position for a horse with acute laminitis is lying down; off its feet. Removing pain medication may be the best thing to encourage your horse to get the 'bed rest' he needs. Bed deeply, and keep a horse friend close to help your horse feel comfortable and secure. Straw can sometimes be too high in sugar, so if your horse likes eating his bed, get it tested for sugar content. Even if your veterinarian chooses to prescribe short term medication in an attempt to limit inflammation, always confine a horse while on pain killing drugs so moving around does not cause more damage.

Find the cause

We cannot prevent future episodes of laminitis without determining the cause of the current episode. If the horse ate a bag of grain, or got loose and ran down a paved road in a panic, the cause is self evident. But many cases of laminitis may appear out of nowhere, with no apparent cause. That's when we have to play detective. Blood work to determine hormonal status is the best place to start.

We feel that the diagnostic investigation of every case of laminitis with 'mysterious' causation should include an endocrine panel to determine levels of insulin, glucose, ACTH and thyroid. Hyperinsulinemia can trigger laminitis. New studies have shown that not all IR horses or ponies get fat, even on pasture, yet the metabolic profile that predisposes them to laminitis can be determined by appropriate blood tests. These tests are inexpensive, readily available and do not require special handling. Grain or high sugar hay may affect insulin levels, therefore we recommend pulling blood at least 3 hours after the last meal. A horse with laminitis should already be off all grain, and on soaked hay, or hay tested and known to be low in sugar, until insulin resistance is ruled out. A baseline ACTH or Domperidone stimulation test should be included to rule out PPID (aka Cushing's). The dexamethasone suppression test has been previously described as the 'gold standard', but recent studies have shown that dexamethasone can cause a dramatic rise in insulin in ponies. It may be prudent to avoid this testing method until insulin and glucose tests have ruled out insulin resistance. Tests for PPID do require special handling, and are not completely reliable from August through October due to seasonal variation of ACTH in even normal, healthy horses. If testing during this period, cases with borderline test results may be put on 1 mg of pergolide temporarily. Then after November, wean off pergolide for 2 weeks and retest.

Pergolide can be very effective at stopping laminitis in horses with PPID, and administration should not be postponed if PPID is suspected. Not all PPID horses are hairy, and laminitis is sometimes the only symptom presented. Not all PPID horses are insulin resistant, and not all insulin resistant individuals have PPID. It is two separate conditions that may overlap.

http://diaglab.vet.cornell.edu/ is our lab of choice. Their website provides instructions for sample preparation, shipping and interpretation for those unfamiliar with endocrine testing.

Abscessing is common after a laminitis attack, and is frequently misinterpreted as a relapse. It frequently presents in only one foot, comes on suddenly, and can make a horse three-legged lame. There may be a bulge or soft spot in the coronary band or sole or localized heat. Call your vet. If the abscess can be found and drained, reduction in pain is immediate, and everybody heaves a huge sigh of relief.

Diet

If insulin resistance is ruled out by blood tests, chances are a previously laminitic horse can resume with the same diet as before after complete recovery, with the following caveat: Previous laminitis from any cause may weaken the structures in the foot and predispose a horse to future episodes. This means we should exercise more caution to assure the horse has no more grain than necessary to maintain a lean body condition. A more gradual introduction to pasture than required previously is advised.

For laminitic horses known to be insulin resistant or not yet tested for insulin, all grain and feed containing grain products should be eliminated immediately from the diet. Hay should be soaked under water for a couple of hours to dissolve and leach out excess sugar. A positive response within a week to hay soaking is a good indication of insulin resistance, and a clue that the hay is not appropriate. Sample 10-15 bales with a hay corer and send to www.equi-analytical.com Try and find hay that is below of 10% Water Soluble Carbs + starch on a dry matter basis. Some horses may be more sensitive, and some may be more tolerant especially if currently sound and in a regular exercise program.

Hoofcare

If you think your horse has laminitis, you should immediately support the boney column to limit rotation and sinking. This can be done by applying blue construction Styrofoam with duct tape. See instructions at:
http://www.hopeforsoundness.com/miscfiles/sty_inst.pdf
Everyone with a horse that is high risk for laminitis should have this ready in their first aid kit.

Successful hoof care treatments include support of the boney column, providing cushioning, setting break-over further back to reduce mechanical stress in the toe region, and encouraging weight bearing in the back portion of the hoof. There are many products and techniques to choose from. Only your horse can tell you which is best. Your hoof care provider should have experience and success in the rehabilitation of foundered horses. This is a specialty. If your horse is not responding with improved soundness after their administrations, ask them or your vet for a referral to a specialist.

Exercise during rehabilitation

When insulin resistance is associated with laminitis, we feel that the practice of keeping horses in a stall long term is contradicted. Movement and exercise improves circulation and insulin sensitivity. As soon as the horse is walking about, on no pain medication, he should be allowed and even encouraged. We like the 'open door policy'. Leave the stall door open, and let him decide when he feels like moving about. Provide soft, supportive.

Barefoot vs shoes

This debate often takes on the fervor of religious conviction, but again, let your horse tell you what he needs. We feel that if you can provide footing that cushions and supports the boney column and enables your horse to move about more comfortably, barefoot is a useful option, especially if you are willing and able to utilize boots and pads as needed to keep your horse comfortable. Sand, pea gravel or soft, loamy soil may provide adequate support, depending on the degree of hoof pathology. Therapeutic shoeing packages may be necessary in situations where footing is not optimum, or the horse does not improve after a proper trim by a hoof care practitioner with previous success in rehabilitating laminitic horses.

Footing such as sand, mud or sod, therapeutic shoes, boots and pads or taped on frog support. To decide when hand walking might be productive, walk the horse 30 steps. If soundess improves, as indicated by longer, quicker, and less tentative strides, go ahead and try 5 minutes. Don't go too far away, and stop anytime they worsen. If they are no worse the next day, continue adding 5 minutes per day. Continued improvement within each session, or day by day is an indication that exercise is beneficial. When the horse begins to trot or canter at liberty, work under saddle at walk on good footing can begin. Let the horse tell you what he can handle, but be cautious, observant and try not to 'over do'. Once your horse is fully sound again, regular exercise is another vital practice for prevention of laminitis in insulin resistant horses and ponies.

Be sure and read next month's Part 3 of this series.