By Tabb Pig, CJF     

When an equine athlete experiences an episode of laminitis or founder it can be a painful experience. While there are numerous studies and articles on the causes of these two maladies, there is also a general consensus on what the hoof capsule experiences after the episodes occur. 

When a horse experiences a bout of laminitis, whether through injury, overfeeding, or metabolic issues, inflammation of the laminae occurs. The anatomy of the hoof is such that the insensitive laminae are attached to the hoof wall and the sensitive laminae are attached to the coffin bone. In the event of hoof trauma, the inflammation and reduction of blood flow can cause partial or total separation of the laminae, allowing the coffin bone to rotate downward. Laminitis can show up as subtle lameness in the front feet, external bruising in the sole, or white line disease. When this happens, the experience can be compared to pulling off your fingernail. 

Obese horses are especially prone to developing laminitis. Photo: ©Dreamstime/Dizajune

The Anatomy of Laminitis and Founder

The relationship between the sensitive and insensitive laminae inside the hoof wall is like interlacing fingers in a tight hold; once they start to loosen, it does not take much to pull them apart. At this point it would be described as founder. In acute stages of founder, the hoof’s exterior would not show signs or symptoms of the disease. Once the bone has rotated, founder can be detected by an x-ray. Because the fragile attachment of the laminae is the support of the horse’s body weight, it is critical to get a hoof care team involved to address the issue fast. Proper diagnosis and treatment are crucial to recovery.

Treatment

Traditional methods of treating founder have varied and progressed over time. With today’s methods, an equine athlete can be expected to recover to a normal life in most cases. Past methods have included heart bar and egg bar shoes, a shoe nailed on backwards, and wedge pads. The only shoe that truly provides any type of support for the laminitic horse is a heart bar. Application of a heart bar shoe should be a very precise procedure, requiring training and x-rays for proper placement. If necessary, a vet may call for pads. In some cases, pads may allow sand and moisture to collect under the pad, which can be trapped between the pad and the foot. If the horse abscesses, the shoe will have to be removed for treatment. With any of these applications, the coffin bone and sole have limited support. Without solar or frog support, there will still be stress on the interior laminae.

The veterinarian, farrier, and horse owner must work together in the diagnosis and management of acute founder or laminitis to ensure the best recovery. Photo: ©iStockphoto/Fotoedu

When a farrier shoes the horse, all of the weight is placed on the hoof wall. When the horse moves, the coffin bone and sole are moving downward toward the ground. This creates more stress on the already inflamed laminae. The goal is to minimize stress, and support the boney column and sole. During this phase the hoof care team strives to relieve the stress between the hoof wall and the laminae. The most effective way to do that is to protect the hoof with a pad or a pour-in pad. These packages are designed to increase surface area for weight bearing so that the sole can take on some of the horse’s weight, and not just the hoof wall. Historically, it was thought that anything you put underneath a pad would help protect and cushion the sole of the horse. This, however, is not always the case. For instance traditional silicone from the hardware store has been used under a pad, despite some of its challenges. Some drawbacks of traditional silicone include: 

• A long set time of 24 hours
• Messy application
• The acid-base can leave a smelly residue
• The material does not absorb concussions, sending the pressure up the horse’s leg

An excellent alternative to traditional pads and silicone filling is a liquid pour-in pad made of urethane adhesive. These products offer a versatile solution that is easy to apply, sets quickly, and produces a soft, resilient supportive pad material.

Advantages of pour-in pad materials include:

• An immediate bond to the sole, sealing out moisture and debris. 
• The pour-in pad material can be filled to ground level for maximum support and effectively absorbs concussion, instead of sending it up the leg like silicone products. 
• The pad provides support to the boney column by loading the entire solar surface with a pour-in pad, and also positions the weight-bearing load over the entire ground surface and not just the wall. This reduces the “pull” on the laminae between the hoof wall and internal structures resulting in a faster recovery and a more comfortable horse.

Above and Below: Pour-in pads are an effective way to help support the sole and relieve stress. They are easy to apply, set quickly, and produce a soft, resilient supportive pad material. Photos courtesy of Vettec

 

Modern liquid pad materials come in different levels of firmness so they will match the needs of the individual horse. The pad materials can be poured to ground level. Even on hard ground, the sole frog and hoof wall bear equal weight. The pads can be customized so that if you do not want to cover an area that may be sensitive, it can be blocked out. Even if the whole sole cannot be covered, a half pad provides 50 percent more support than not having one. 

Managing a horse’s acute founder or laminitis can be a challenge, and it’s important to have a good team in place to diagnose, manage the treatment, and ensure recovery of the equine athlete. There are a number of treatments on the market today, but consider ones that will help relieve the internal stresses within the hoof capsule and support the boney column, providing a speedier recovery and a more comfortable horse. Using liquid pad technology, veterinarians and farriers now have the ability to use materials that will bond to the foot and withstand the weight of the horse.

Main Photo: The characteristic stance of a laminitic horse includes hind feet brought forward under its belly in an effort to take weight off the front feet, which are stuck out in front of its normal centre of gravity. Photo: Bob Langrish