In a healthy hoof, the hoof wall is tightly attached to the bone inside with structures called laminae, similar to the closing action of a zipper. When your horse develops laminitis, the inflammation of these laminae is extremely painful, since there is no where for the swelling to expand within the hard hoof wall. It would be similar to you bruising your fingernail, although your horse also has to support its entire body weight on its painful digit.
Diagram of a horse' hoof with laminitis
In spring, the biggest environmental risk for laminitis is new grass, with high sugar content. It is theorized that this increased carbohydrate load may cause a proliferation of hindgut bacteria, which is thought to trigger an enzyme release within the hoof, leading to damage of the sensitive laminae. For horses with metabolic diseases such as Cushing’s disease, insulin resistance, or weight issues, new grass carries an even greater risk. Ponies and some breeds, such as Morgans and Arabs are also at greater risk.
While grass, or grass hay, is the most appropriate feed for a horse, many grass seed varieties available today have been selected for increased nutrient and sugar content. This means that you may need to restrict the amount of grass available to your horse. A grazing muzzle is another option, which may allow a horse to remain in pasture with its herd mates, while decreasing the volume of sugar rich grass it consumes.
What are the signs of laminitis?
Attitudinal signs can include: depression, or anxiety/trembling.
Movement signs can include: reluctance to move, difficulty turning, exaggerated steps with hind legs, tender on gravel, exaggerated heel first landing, stiff gait, rocking back on heels, shifting weight from one foot to the other, or tight muscles.
Physical examination can reveal: elevated respiratory rate with panting/sweating, strong bounding digital pulses, excessive heat in hooves, bulging sole, and pain when pressure is applied to the sole.
Is laminitis an emergency?
Absolutely. The first 24 hours of an acute (new) laminitis case is critical to preventing permanent damage to the laminae. We would advise that you call our office immediately. Therapies would likely include: long-term ice bathing, anti-inflammatories, deep sand or organic bedding, strict stall rest, diet changes, pasture management, padded boots, and working with your farrier towards corrective trimming. Radiographs (x-rays) are not critical in the early phase, but may be considered several weeks after the acute episode.
What happens after my horse has recovered?
After recovery, there may be other strategies you need to implement to prevent a future episode. Examples include:
sourcing low-sugar grass hay,
testing the hay you have on-farm,
using a slow-feeder,
working with a nutritionist to find an appropriate low-sugar mineral supplement,
paddock design to increase exercise, and
testing for metabolic disease.
Proper hoof care will also become essential to preventing future episodes. We would recommend against putting shoes on a horse suffering from laminitis. However, a physiologically correct trim will ensure the hoof mechanics work with the hoof, not against it.