Founder & Laminitis an Overview

Founder and Laminitis in Horses

by Robert N. Oglesby DVM

Introduction

Introduction » Symptoms » Diagnosis » What Exactly is Founder? » Acute vs Chronic Founder » Causes of Founder » Treatment » Severe, Unresponsive Founder » After the Pain Has Gone: » Prognosis » More Info & Discussions

Whether you call it founder or laminitis the characteristic lameness and stance of a horse with laminitis is easy to recognize: the horse will have a short-strided stiff gait. Though laminitis has been described for as long as man has cared for horses and could write about it, this is a disease that just recently we are beginning to understand much better particularly at the cellular and molecular level. This along with a better understanding of the physical forces that effect the foot and how the circulation of the foot works is leading us to more rational and effective treatments. Laminitis is often treatable though occasionally you run into the bad case that defies treatment. This article explains symptoms and diagnosis, factors that predispose to founder, current theories on causes, and reviews the treatment of founder and laminitis, both traditional and experimental. Links to more detailed articles on causes are provided.

Symptoms

Introduction » Symptoms and Examination » Diagnosis » What Exactly is Founder? » Acute vs Chronic Founder » Causes of Founder » Treatment » Severe, Unresponsive Founder » After the Pain Has Gone: » Prognosis » More Info & Discussions

The lameness associated with founder is often easy to recognize and results from the combination of both front feet being sore at the toe about the same amount and more sore than the rear feet. The back feet may be involved too, but the front feet bear 50% more weight than the rear so in most cases they hurt more. Important is to do a complete exam and history to rule out other causes of a stiffly moving horse and possible causes.

Gait and Stance

Since both feet are sore the foundering horse does not really limp but slowly steps with short strides making the horse or pony appear more "stiff" than lame. One of the best clues is watching the horse go across soft even ground and compare it to walking on a hard surface. Horses with sensitivity in the feet will shorten up on the harder terrain.

When the founder is moderate to severe, he will attempt to get weight off his front feet when just standing by:
  • Shifting weight back and forth on the front feet
  • Stand with his front feet propped out in front of him while leaning back on his rear legs
  • As the pain worsens he may start spending a lot of time laying down.
When mild and uncertainty exists you can try and get a clue if it is the feet by lifting one front foot for 10 seconds. Does the horse become uncomfortable on the other and lift it off the ground once the foot you are holding is placed back down. And does this happen from the other side. If the horse can trot circles on lunge both ways is there a lameness that switches back and forth to the inside foot?

Examination of the Feet

Examination of the feet usually will find a warm foot that has an increase in the digital pulse. There may be swelling of the coronet band or in severe cases a depression caused by the dropping of the coffin bone. Examination of the sole and application of the hoof testors may be hindered by the horse's unwillingness to put all of the weight on the opposite front foot. If you can get hoof testers on the horse the toe area is often sensitive.

If there is still uncertainty you should consider other causes of a stiff shortened gait, see "Other Rule Outs" below. Blocking the feet relatively high in the pastern is one way of ruling in the feet as the cause of the lameness. First block one foot then the other. This will provide immediate localization with the first block having the unblocked foot go lame and then near soundness returning with both feet blocked. Note the horse should not be moved around a lot while blocked. If your stiff short gaited horse does not block out at the feet consider the other rule outs.

Other Rule Outs

Some cases can be a little more difficult with the only obvious sign being a shortening of the gait or stiffness which can be due to other causes. This will need to be differentiated from a sore neck, mild tying up episode, and bilateral bruising of the sole:
  • Neck Soreness: Because the horse uses his neck to help him move a sore neck often makes a horse appear stiff all over when moving. Usually there is a recent history of a intramuscular neck injection, particularly vaccinations or penicillin in the past week. Blunt trauma to the neck can also cause stiffness. An important difference is the horse with a stiff neck will have trouble reaching to the ground for food and resist manipulation of the head from side to side. Palpation of the neck should reveal painful areas ...more
  • Tying Up (Rhabdomyolysis): Usually the muscles of the rump and thigh are stiff and painful to deep palpation. Horses may camp out but usually the back legs are not up under the horse like founder. Muscles enzymes will absolutely rule in or our tying up ...more.
  • Bilateral Bruising: Bilateral bruising of the front feet can be a tough differential for laminitis. The two conditions will appear almost identical. In fact severe bruising may lead to founder so it may be difficult to tell where the bruising ends and the founder begins. Radiographs of bruising should not reveal rotation amd might help. A good rule of thumb should be if it is possibly founder treat it as a founder. After all the treatment for the two conditions are almost identical so error on the safe side until proved different ...more.

Diagnosis

Introduction » Symptoms » Diagnosis » What Exactly is Founder? » Acute vs Chronic Founder » Causes of Founder » Treatment » Severe, Unresponsive Founder » After the Pain Has Gone: » Prognosis » More Info & Discussions

                       
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