by Brenda Jackson, UGA Extension, Murray County and Dr. Kylee Jo Duberstein, Professor, Equine Science, Department of Animal and Dairy Science
Laminitis and founder are often used interchangeably in regards to issues with the hoof but subtle differences exist between these two terms. Laminitis specifically refers to inflammation of the laminae of the foot and is typically divided into stages. Founder, on the other hand, refers to displacement of the coffin bone in the hoof as it begins to rotate or sink within the hoof capsule. Founder is a potentially severe outcome of laminitis. It is important to seek veterinary assistance when laminitis is suspected because prompt treatment can mitigate damage to the hoof and improve the horse’s outcome. A veterinarian can perform proper diagnostics, including radiographs of the hoof to assess the position of the coffin bone in relation to the hoof capsule and form a treatment plan to manage inflammation and provide support for the coffin bone.

3 Stages of Laminitis:
- Developmental – The developmental phase of laminitis occurs after exposure to a causative agent or event. During the developmental phase, the horse does not show clinical symptoms of laminitis. However, pathological changes to the laminae of the hoof are beginning to occur.
- Acute – Lameness signs begin within hours or days due to acute inflammation in the hoof. You will likely feel an increase in the digital pulse, the hoof will feel warm/hot. Any swelling will be internal so you won’t see it. What you will see is constant shifting of weight off the front feet; it might appear as if they are “rocking” back and forth or standing with all their weight on the back feet. They may be unwilling to walk/move or rise from a laying position. In severe cases, inflammation in the hoof will cause weakening in the structure of the laminae which allows the coffin bone to rotate or displace from normal position. It is important to note that laminitis is more common in the front hooves, which leads to the classic rocked back stance. However, the hind hooves can be affected in addition to the front feed, and less frequently, laminitis can occur in the hind feet alone which can lead to different lameness symptoms.
- Chronic – Long term damage to the hoof structure is referred to as chronic. Displacement of the coffin bone can be measured on radiographs. Outwardly, the hoof may start to take on a dish appearance in the hoof and ridges may be observed on the wall of the hoof as it begins to grow out from the coronet band.
The acute tissue inflammation in the laminae of the hoof is what causes the pain associated with laminitis, which can range from mild soreness to severe separation of the coffin bone. Causes of this inflammation will vary by horse, ranging from too much grain (non-structural carbs) in the diet, eating toxic plants, pasture associated laminitis (also non-structural carb related – obese or insulin resistant horses are prone to this version), working on hard surfaces (road founder) or systemic inflammatory response syndrome (SIRS).
The first step in preventing laminitis in your horse is to focus on hoof care. Conduct daily hoof inspections for rocks, wounds, cleanliness around the frog, etc. Have regular farrier visits to ensure hooves are balanced appropriately, toe angles are correct for your horses’ conformation and are the proper length. In cases where your horse has a limb injury, provide adequate support for the opposite limb to avoid “supporting limb laminitis.” Store grain securely so horses cannot get into it by accident. For high risk horses (those that have had episodes in the past or are insulin resistant) ensure they have a balanced diet that limits non-structural carbohydrates such as sugar and starch. You can also limit access to pastures, particularly in months where cool season grasses produce higher levels of non-structural carbohydrates (spring/fall), by using a grazing muzzle.

For a horse with laminitis, treatments will vary by veterinarian and animal, usually in response to the severity of the diagnosis. Initial treatment will revolve around minimizing progression of the disease – pain management and supportive care until inflammation subsides. It is important to identify the inciting factor and eliminate that to prevent recurrent episodes, and then work to prevent further damage to the laminae while maintaining blood supply to the hoof. Acute laminitis treatment often includes
- Stall rest with deep bedding
- Non-steroidal anti-inflammatories (NSAIDS)
- Cold therapy – either a cold-water hose, ice bath or “ice boot”
- Farrier treatment to support the coffin bone and encourage normal hoof growth
- Dietary management to minimize sugars and carbs and limit access to lush pasture
If laminitis is caught early, the severity can be minimized. The outcome will depend on the severity of acute inflammation, and displacement of the coffin bone (if any). Prevention of laminitis requires minimizing risk factors, and in many cases, paying close attention to the horse’s diet. The majority of laminitis cases (as much as 90% according to some reports) are endocrinopathic in nature and typically involve insulin dysregulation. It is critical to manage the horse’s diet to keep the horse at an optimal body condition score. Additionally, owners should work with their veterinarian to diagnose any underlying conditions that may lead to insulin dysregulation. For horses that are insulin dysregulated, it is often recommended to restrict levels of non-structural carbohydrates (NSC) in the diet to approximately 10% (e.g., provide forage and concentrates that have an NSC of 10% or lower). Your county extension agent can assist you with learning how to body condition score your horse as well as testing forage and feed for NSC levels.
Sources:
Hoof Care for a Horse with Laminitis and or Founder. Doug Butler, PhD, CJF, FWCF, https://equimed.com
Laminitis in Horses. Brian Beasley, DVM, UGA, MSD Veterinary Manual, https://www.msdvetmanual.com/musculoskeletal-system/disorders-of-the-foot-in-horses/laminitis-in-horses
Laminitis. UC Davis Center for Equine Health, https://ceh.vetmed.ucdavis.edu/health-topics/laminitis