What is Laminitis?
Laminitis is a condition affecting the soft lamina tissue that holds the coffin bone of the hoof in place and connects this bone to the inner hoof wall. When a horse becomes laminitic, the tissue becomes inflamed. Inflammation leads to swelling and the rigid hoof wall or capsule does not allow for swelling. Much like the pressure created in the skull with head trauma, swelling in the hoof will increase the pressure within the hoof. This increased pressure can collapse or compromise the blood supply as blood vessels are easily compressed. This compromises oxygen delivery to vital tissues and this can result in damage or death to soft laminar tissue. As the tissue dies, it no longer has the ability to hold the coffin bone in place. As the support from the lamina is lost, the coffin bone may pull away or “rotate” and this is excruciatingly painful and in most cases permanently changes the hooves for life.
Laminitis, if treated early, can in many cases be reversed before permanent changes occur. Founder is the lay term that is most accurately applied to advanced laminitis that has resulted in permanent changes and recurrent episodes of lameness. Severe uncontrolled laminitis results in the coffin bone rotation that creates crushing pressures on the sole beneath the tip of the coffin bone. Left untreated, the coffin bone can eventually pierce through the bottom of the sole exposing the bone to infection and even higher levels of pain and suffering.
Knowing the Signs
Recognizing laminitis at the onset is key to treating the disease. Look for the following signs:
- The digital artery (felt just above the ball of the hoof or at the fetlock) will have a strong or heavy thumping pulse. As horses can become laminitic in one or all four feet, it is important to know what your horse’s normal hoof pulse feels like. Heat in the foot can also be an indication, but is less reliable than checking for a strong pulse.
- The horse’s gait may become irregular and stifled, even at the walk. This can be most obvious when they are asked to turn.
- If a horse is laminitic in both front feet it will roll back on its hind end, shifting most of its weight to the rear. It will generally stretch out its front legs to bear weight on the heels of the front feet to relieve pressure. This is known as the ‘laminitic stance.’
- If a horse is laminitic in all four feet you may see it continually shifting its weight from one foot to the other to relieve pain. It may also lie down and be reluctant to get up.
- If the coffin bone has begun to rotate and slip downward (founder) you can often see an indention just below the coronet band. If the founder is advanced, you may see an indention below the coronet band around the entire hoof.
- The toe of the hoof tests positive (causing pain) when hoof testers are applied.
Laminitis is a very serious condition and can set in suddenly with no obvious cause. If a horse is running a high fever, is ill, is in a very stressful situation like colic, or is post-surgery, be on the lookout. Swift medical attention will be needed if you suspect your horse is developing laminitis. It is the second leading cause of death in horses.
Please contact your vet immediately if you suspect your horse is suffering from laminitis or have any questions about prevention.
Mid-River’s Equine Hospital is available 24 hours a day for emergencies at (636) 332-5373.