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Equine Laminitis
EQUINE LAMINITIS
Laminitis is lameness in the front feet of a horse or cattle. It is a painful inflammatory condition of the tissues and the disease can affect any horse of any age or sex at any time of the year. Severe lameness of the front hooves causes cellular death and laminar disruption. This is a serious disease which can lead to death.
There are thousands of different causes of laminitis. It is associated with diet and diet changes, especially obesity because the horse will have to carry more weight per leg so the bones and the tissues will get damaged. Working on hard ground and over exercising can also damage the foot and cause laminitis. Improper shoeing causes sole pressure which might trigger laminitis. Vascular system in the foot is also an important factor since the tissues called laminae need a lot of blood supply.
The disease starts with the separation of the coffin bone and the inner hoof wall. The coffin bone is attached to the hoof wall with a tissue called laminae. They are layers of connective tissue. Tissues get inflamed and blood supply is disturbed causing the attachment between the laminae fail. So the hoof wall becomes separated from the rest of the foot. Pain and swelling of the foot begins.
If we talk about the anatomy and the physiology of the hoof, we can say that it is a highly keratinized epidermal structure. It has not got any blood vessels or nerves. The wall at the toe is the thickest and it thins towards the heels. The thickness is important when it comes to designing horseshoes or driving horse nails. Another important thing is the angle formed by the dorsal surface of the hoof wall with the ground surface. For the fore feet it should be 48-60 degrees and for the hind feet the angle should be 50-62 degrees. The skeleton of the foot consists of the proximal, middle, and distal phalanges, the cartilages of the distal phalanx and distal sesamoid bone.
Some clinical signs a horse with laminitis can have are; bounding pulse in the arteries, hot feet, weird posture with its front limbs stretched out and hind legs underneath its body in order to decrease the weight load. There might be an increased temperature of the sole. The horse can have anxiety or visible trembling. If the situation is too severe, patient will remain recumbent.
In acute laminitis, diagnosis is based on history and posture of the horse. The feet should be checked for inflammation doing a physical exam. We should look for increased temperatures of the hooves. A radiograph of the affected feet is useful since we need to have a clear understanding of what is going on inside the foot.
In order to treat laminitis anti-inflammatory agents can be used such as flunixin meglumine but it can be toxic as a side effect. Heart-bar shoes can diffuse sole pressure and avoid pedal rotation. A side effect is aggravation of the pain if improperly fitted. Over dosage of drugs cause ulceration and bleeding from the intestines. They also mask the lameness so people exercise the patient more, making the situation worse.
Shorty and long term expectations depend on the duration of acute laminitis; number of feet affected and amount of rotation. Some horses might need lifelong treatment; some of them do not get better so they get euthanatized. According to the lameness grading system the horse can die, get destroyed, and can be used as a pet. Some horses respond well to the treatments and return to athletic career.
To conclude, there are a couple of precautions you can take to prevent laminitis such as; weight control, restricting access to lush pastures, proper trimming and shoeing by an accomplished farrier. Laminitis is a serious disease which should not be underestimated.