Laminitis causes the breakdown of the internal supporting the structures (laminae) between the external hoof wall and the coffin bone inside the hoof. The laminae deteriorate when excess activation of enzymes known as Matrix Metalloproteinases (MMP's) cause the attachment of the laminar cells to break loose from their basement membrane. This results in the destruction of the normal blood supply to the laminae and causes severe pain to the horse.
- Carbohydrate overload - over-eating of grain
- Consuming too much fast growing, lush grass in the spring and fall
- Retaining placenta infection that follows failure to expel the afterbirth within a few hours of foaling
- Mechanical damage to the feet from excessive concussion on hard surfaces
- Metabolic stress such as becoming overheated
- Ingestion of Black Walnut shavings
- Hormone related changes due to Cushings disease
- Drug induced Laminitis from using corticosteroids
- Any serious illness may lead to laminitis
|Rotated coffin bone|
- There may be shifting of weight from foot to foot.
- A slight stiffness of gait may be detected.
- The horse will not want to move, and often assumes the "founder stance", with all four feet forward of the normal position, head low and back arched.
- The horse may lie down and not want to get up.
- Sweating, shallow breathing and a fever are typical.
- The feet may be warm to the touch and usually a pulse can be detected on the back pastern, below the ankle.
- From one to all four feet may be involved; most commonly the two front feet are affected.
- Unfortunately, when symptoms of Laminitis/Founder Syndrome are first noticed, the disease process may have already caused irreversible damage, therefore it is important to call your veterinarian immediately. The first 24 hours after onset may be critical to the outcome.
These guidelines are meant to serve as an overview to the general principles in treating and preventing Laminitis. Each case is different and must be treated individually. It is not the purpose to advocate a treatment for all cases, as this is impossible. It should be left to the attending veterinarian and farrier to make the final decision on how to manage each individual case.
Make every attempt to determine what caused the onset of laminitis and prevent further exposure. The cause is often difficult to determine, but since we do not understand the ‘trigger mechanism’ of the disease, the cause must be eliminated, even if the horse is recovering. Some of the possible causes of laminitis are: diet and grain overload, allergic reaction of any type, excess concussion to the feet, reaction to bedding, bad water supply, post-parturient retained placenta, aftermath of colic, diarrhea, severe myositis and excess stress such as hauling and prolonged exposure to high temperatures.
Many horses develop infections due to the death of tissue in the feet. If infection is present (this is not always easy to determine) the feet must be opened to establish drainage of the infection. The feet must be soaked in a warm disinfectant solution (Lysol, betadine or epsom salts) daily. They should be packed with a mild antibacterial salve and kept bandaged until the soles are healed. If fecal material is allowed to continue to get into the feet, the infection will persist.
Some supportive device should be used to stabilize the bone in the foot if there has been enough damage to the laminae to cause any degree of separation. This includes ‘lily pads’, styrofoam pads, or corrective shoes such as heart bar shoes, which support the coffin bone to prevent further separation of the laminae. Only a skilled farrier should put on these special devices with the assistance of radiographs and the presence of the attending veterinarian. If these are not applied correctly they can cause considerable damage. Care should be taken in selecting a farrier. Again, not all cases of laminitis need these shoes, only the more severe cases. These shoes have been used in many chronic horses with success to prevent continual breakdown of the laminae in the chronic foundered foot.
The use of excessive and prolonged drug administration may confuse the status of the horse and possibly be detrimental to the case. In the early stages, the use of non-steroidal anti-inflammatory drugs (i.e., bute, banamine) seems very useful, but beyond this point they only make the horse feel better. They are not really involved in the healing process, and may be detrimental in some cases. Therefore, we advocate using minimal amounts of drugs so that the real status of the feet may be evaluated and not be masked by these drugs. This is often difficult for horse owners to do since they don’t like to see the horse in discomfort. However, this may be necessary in order to evaluate the progress of the case and to tell if the feet are continuing to refounder. Often the best thing is for the horse to lay down and relieve the pressure on the damaged laminae.
The effect of exercise may vary in each case. If a horse has severe damage to his feet, exercise (especially early in the disease) may make the horse worse. As time goes on, the amount of exercise may be increased. A rule of thumb to use may be that as you start to exercise the horse and he seems to improve after a short amount of walking, then it is probably helping. However, if he seems to get worse or is very reluctant to move, you should discontinue the exercise and allow more healing to occur before you start to try again. Generally, as horses are recovering you can increase the time you walk them. If you overdo the exercise, the horse will usually be sore the next day so you will know you did too much. Use a surface that is free of rocks and hard material that would put excess pressure on the soles.
Diet is probably one of the most important areas in the treatment of laminitis as well as the one that we seem to understand the least. It is probably safe to say you should reduce grain intake and increase roughage in the diet. We recommend that corn and alfalfa hay be removed from the diet, as they often seem to be incriminated as a causative factor. The diet we currently feed consists of 3 parts oats to 1 part bran. The average amount of feed given to a 1,000 pound horse is 3-4 pounds total per day. The diet is fed in conjunction with good quality grass hay. It is beyond the scope of these guidelines to discuss all the extra supplements used for the treatment of laminitis.
Chronic obese-type laminitic horses and ponies require no grain, but can be fed good quality dry grass hay. They should not be allowed on grass pastures, particularly in the spring and fall of the year. Sometimes the use of thyroid supplement seems to reduce the incidence of reoccurrence in these animals. They suffer from a form of metabolic disease associated with being overfed. They require little to live on because their genetic makeup allows them to survive in areas with little available food. Their exposure to excess food causes changes in hormones, which increase the appetite and seem to influence the breakdown of laminae in the feet. Many of these conditions can be reversed after a prolonged reduction in food intake. However, many animals have had so much damage to their feet that cold weather, shoeing and other minor insults to the feet result in painful bouts with the disease. These cases are very difficult to manage.