Laminitis and founder
Laminitis can severely affect a horse's wellbeing. Horses of every breed, age and sex can get affected. Laminitis can lead to founder which can be life-threatening. So what happens exactly, why and what can we do?
Did you know the terms laminitis and founder do not mean the same thing? Laminitis is a disease of the feet. It literally means “inflammation of the lamini”. The lamini are what make the connection between the pedal bone (also known as coffin bone or P3) and the hoofcapsule. The pedal bone is suspended in the hoof by these lamini, which keep the bone firmly in place. This is necessary because the horse’s weight would otherwise otherwise move it. When the lamini inside the foot become inflamed, the local swelling that goes with it causes the lamini to separate, lose their grip and the connection between the bone and the hoof wall becomes unstable.
When the lamini lose their grip, the forces that are put on the pedal bone can cause it to shift. The horse’s bodyweight can cause the pedal bone to sink down inside the hoof. The deep digital flexor tendon, which attaches to the pedal bone, can cause the bone to rotate by pulling the toe tip backward. When these incidents occur, it’s commonly called “founder”, or a sunken bone can be called a “sinker”. In severe situations, the bone can even push through the sole of the foot.
As you can imagine laminitis is an extremely painful condition. An acute episode of laminitis is an emergency situation that needs to be handled by a vet ASAP! If this does not happen in time, the horse can start to founder. Once the pedal bone sinks or rotates, the prognosis becomes poorer.
Horses that have acute laminitis have painful feet and therefore don’t want to walk or pick up their feet. Their digital pulses may be felt in the pastern area and their feet may be warmer than normal. Laminitis can happen in one foot, both front feet or all four feet at the same time. It the pain is mainly located in the front feet the horse may shift its weight back. If the hindfeet are more painful than the front feet the horse may shift its front legs further under its body. A horse may just lie down to get off its feet.
Chronic laminitis leads to disturbed hoofgrowth. Hoof growth becomes retarded in the front side of the foot, which makes the heel area grow relatively faster. This leads to diverging growth rings. The white line, visible in the hoofwall on the solar surface, may become widened.
If your horse is showing signs of laminitis, call a vet immediately and don’t move or feed your horse until the vet is there. Putting ice or rags covered with with cold water on the feet can help. The inflammation needs to be stopped medically before the horse founders. The vet can inject anti-inflammatories to help stop the inflammation in the foot as soon as possible. Anti-inflammatory treatment is then continued orally daily. However, in some cases euthanasia may be in the best interest of the horse. Radiographs may help with this decision.
In the first weeks your vet will have regular contact to assess progress and determine when to safely stop medication, when the horse can resume in-hand walking and to treat the underlying problem that lead to laminitis. Response to treatment will help determine prognosis. If initial treatment results are positive, horses may be managed long term with corrective trimming, special shoeing if needed, and by staying on top of the cause to prevent relapse. Radiographs may be advised, to see whether the bone has rotated or sunken. Radiographs can also be used to determine optimal hoof trimming strategies. If a horse does show signs of founder and isn’t responding enough to treatment, good quality of life may not be achievable, in which case euthanasia has to be considered.
Laminitis is a serious condition that can have lifelong effects on a horse (and therefore the owner). It is therefore important to find the cause of laminitis and treat it, otherwise it is likely to recur. Laminitis is most often caused by insulin resistance, which may be due to overweight, PPID or old age. Prevention is better than treatment, especially because the consequences of laminitis can’t all be cured. If you think your horse might be overweight, have PPID/Cushings or has become senior, let your vet do a health check. Your vet can test your horse's insulin and help you address any issues.
On rare occasions laminitis can also occur in horses that have certain orthopaedic or endotoxaemic health issues, which they are usually already getting veterinary attention for.
Do you have questions about laminitis or founder? Or do you think your horse might be at risk? Give us a call.