This all-too common disease is one to be prevented, not treated. It is complex, with multiple precipitating causes, and its very difficult and frustrating to treat. Horses affected by laminitis (founder) often suffer prolonged and severe pain. Consider laminitis a medical emergency – ring CVH immediately if you suspect your horse is developing signs of founder.
What happens when a horse becomes foundered?
Laminitis is an inflammation of the layers of very sensitive tissue inside the horse’s hoof that secure the pedal (or coffin) bone to the hoof wall. When inflamed, these laminae can separate from the outer hoof wall. The separation causes the pedal bone inside the hoof to rotate down towards the sole. In severe cases the pedal bone will penetrate the sole of the hoof. Laminitis can affect one or all feet, but is most often seen in both front feet. Regardless of the number of feet affected the disease is immensely painful.
What causes laminitis?
Laminitis is always secondary to a medical condition, and it has multiple causes and risk factors.
- One of the most common is obesity. The classic founder case is a fat pony allowed unlimited access to lush feed with no exercise. New research has found this particular metabolic disturbance may be associated with impaired insulin function, similar to pre-diabetes in humans.
- Sudden intake of carbohydrates – for example, if a horse gets access to large amounts of grain – can cause acute and severe laminitis. This is extremely urgent – don’t wait for symptoms to appear, ring immediately.
- Maintenance diets high in carbohydrates (eg grain) can be dangerous for susceptible horses.
- Acute infections, including uterine infections following retention of membranes for more than 8 hours post-foaling, can initiate founder.
- Laminitis has now been linked to the hormonal disease Equine Cushing's Disease - read more here.
- Previous episodes of laminitis predispose a horse to future founder unless the cause in that particular horse is managed carefully.
- Severe colic.
- Excessive concussion to the feet.
- Researchers are also exploring the possibility that some horses may be genetically predisposed to founder.
Symptoms
The typical foundered horse is reluctant to move or walks gingerly. The horse stands with feet apart, leaning backward in an attempt to take pressure and weight off the toes (what we call a “sawhorse stance”). The feet are hot and the horse may shift from foot to foot and lie down frequently. The pain causes an increase in temperature, pulse and respiration rates.
In chronic cases, the hoof shows significant changes. The soles will “drop” and the hooves take on a dished "Aladdin-slipper" appearance ie the hoof at the heels grows faster than at the toes. Overweight horses develop a classic solid crest on the neck.
Prevention
- It’s far better to manage your horse’s health and prevent laminitis.
- Keep all grain stored securely out of reach of horses.
- Introduce horses to rich pasture slowly.
- Call us if you suspect your horse has an infection. Never neglect retained membranes – they must be removed as soon as possible.
- Be aware that stress of any kind can also initiate laminitis.
Treatment and management
Laminitis is a medical emergency. Please ring us immediately if you suspect your horse is showing signs of founder. The sooner treatment is initiated, the better chance your horse has to recover.
Depending on each case and diagnosis of the cause, our treatment will include:
- Immediate and ongoing pain relief.
- Antibiotics if an infection is suspected.
- In grain binges, mineral oil via stomach tube will aid in emptying the gut. These horses can be extremely ill and may require intensive treatment with I/V fluids and antibiotics.
- Stable the horse on soft ground (sand or shavings) and leave the horse lying down if that’s its preference – this helps take pressure off the inflamed laminae.
- For overweight horses, immediately modify the diet and implement a weight loss regime. Remove the pony or horse from lush pastures and avoid all grain (this includes grasses with seed heads). The best diet consists of a (small) daily ration of lucerne. Lucerne is high in protein and lower in carbohydrates – this provides nutrition as well as aiding weight loss.
- Longterm diets for recovered horses should provide adequate (ie not excessive) nutrition through high quality, low carbohydrate forage.
- The feet need to be managed in both acute and chronic laminitis. Acute cases may benefit from frog supports, therapeutic shoes or pads. In longstanding cases, the hoof must be regularly and carefully trimmed so the pedal bone sits more normally within the hoof. Therapeutic shoes will lower the heel and lift the toe (taking pressure off the rotated pedal bone).
- We may recommend radiographs (X-rays) of your horse’s hooves. This allows us to assess how much rotation of the coffin bone has occurred and helps with decisions re trimming and shoeing.
What’s the outlook for foundered horses?
Many horses recover with treatment and, when managed well, continue to live healthy and useful lives. Horses that have binged on grain have a poor prognosis. In these cases, the damage to the hoof can be irreparable even if the horse recovers from the accompanying severe gastrointestinal and other medical symptoms.
In less acute cases, management of diet combined with a good farrier able to undertake remedial trimming and therapeutic shoeing can aid recovery and a good longterm prognosis.
Remember, once foundered a horse is highly susceptible to future episodes.
Research
Pennsylvania University in the US, along with universities around the world (including the University of Queensland) is undertaking major new research on the causes and possible diagnosis and treatment regimes for laminitis through its Laminitis Research Initiative.
The availability of the horse genome sequence since 2009 has made research into genetic susceptibility achievable, and the University is also exploring insulin impairment as well as undertaking stem cell studies. The stem cell study is exciting as a potential future therapeutic method. That is, using stem cells for tissue regeneration in the laminitic hoof, similar to regenerative medicine for burn victims and corneal scarring.