Laminitis or Founder

Structure of the foot of a horse, c1907 (c1910)
Laminitis is inflammation within the hoof wall. Print Collector / Getty Images

The onset of laminitis is an emergency. If you suspect laminitis, you must call a veterinarian.

The hoof wall that makes up the hard outer capsule meshes to the flesh-like laminae beneath it with finger-like projections somewhat akin to hook and loop fastener. If the laminae become inflamed, you will see the symptoms of laminitis. Because the laminae are encapsulated by the hard hoof wall, there is no room for swelling, and the horse will be in severe pain. Quick veterinarian treatment of laminitis is essential. If you are reading this because you suspect your horse may have laminitis, stop now and call your vet. The sooner your horse has treatment, the more hope you'll have for a good recovery.

Other Names for Laminitis

founder, road founder, grass founder

Causes of Laminitis

There are many reasons horses develop laminitis. Grain or grass overload are the most common causes and ponies are most susceptible to laminitis caused by grass overload. Ponies can live on very spartan rations, and can easily overeat on good pasture. A half-hour on lush pasture can be enough to founder a pony. This is also why feeding grass clippings to your horse is a bad idea. Laminitis can be caused by excessive concussion.

Horses can be injured after being ridden long and hard down a hard surfaced road. The laminae and hoof wall can be separated and the horse will spend long painful months while the hoof wall re-grows. Bacterial infections and viruses can cause laminitis as can colic. That is not to say all horses that get bacterial infections, such as a mare with retained afterbirth, will get laminitis. But the possibility does exist. Once a horse has had laminitis, it is more likely it will have further attacks. Anything that disrupts the healthy blood flow to the hooves can cause laminitis. Other contributing factors can be:

  • Stall bedding that contains black walnut wood shavings.
  • Grass that has been frozen and thawed.
  • Drug reactions
  • Severe colic.
  • Metabolic diseases.
  • Poor shoeing and trimming.

Symptoms

There are degrees of acuteness in laminitis that range from mild to severe. The initial symptoms of laminitis are heat in the hoof wall, coronary band and sole, with an obvious pulse in the arteries in the hoof area. The horse may show signs of distress and shock with shaking, sweating, increased pulse, body temperature and respiration. In very severe cases, the coronary band may weep body fluids mixed with blood. The bones within the foot may start to rotate.

The horse may walk and stand in such a way that the horse shifts its weight to the back, rather than front quarters avoiding pressure on its front hooves or try to remove the weight from all hooves. The horse may lie down and be unwilling to get up. When the horse stretches its self backward to relieve the pressure on the front hooves, the position is called pointing. Even after the initial symptoms subside the horse may continue to point because of continued pain, continue to show severe lameness and be reluctant to move taking short, quick steps. The hoof wall may grow laminitic rings as it grows out or may separate from the internal hoof structures. The hoof may grow out narrower, with the heels dropping. In extreme cases, the internal bones of the hoof may rotate so they penetrate the sole.

If the laminitis is mild, and all that is seen is a reluctance to walk over hard surfaces and heat in the hoof, radiographs may be taken to confirm the diagnoses. It is possible for a horse to have laminitis only in the front hooves, all of the hooves or only one hoof, depending on the cause.

Treatment

Quick action is required if you suspect your horse is suffering from laminitis. Veterinarian assistance is essential. While you are waiting for the vet, keep the horse still in a deeply bedded stall or on a surface like soft sand. If the laminitis is from eating too much grain, the vet may administer mineral oil to move the remaining grain quickly through the digestive system. Your veterinarian may suggest cold packs to the hooves. Your veterinarian may also suggest painkillers such as NSAIDS, Butazone, and Banamine being two commonly used drugs. Vasodilators may also be administered. Home remedies at the early stages are not a good idea. Your veterinarian will know the best course of treatment.

Prevention

Avoid putting horses out on lush grass suddenly and introduce spring or fast-growing pastures slowly. Take extra care with ponies, or any horse that is an easy keeper and gains weight easily. If you're like me and have a mare that tends to have a fat neck (cresty) and puts on weight by just looking at a round bale, be careful introducing pasture and be cautious with concentrates like sweet feed. Keep a lock on the feed room or bin, so horses can't steal grain if they escape from their pasture or stall.

Gradually increase the workload on a horse. Being a weekend warrior on horseback may not be a great idea for your horse. Avoid riding fast on very hard surfaces such as cement, rocks or tarmac for long periods of time. In addition to being unsafe and hard on your horse's joints, prolonged pounding over such surfaces can cause founder. If your mare has had a foal, and all appears to be well, it is still a good idea to have the vet out to check the mare.