What is Laminitis?
From Wikipedia: “Laminitis is a disease that affects the feet of hooved animals (ungulates) and it is found mostly in horses and cattle. Clinical signs include foot tenderness progressing to inability to walk, increased digital pulses, and increased temperature in the hooves. Severe cases with outwardly visible clinical signs are known by the colloquial term founder, and progression of the disease may lead to perforation of the coffin bone through the sole of the hoof, requiring aggressive treatment or euthanasia.”
What is the Affected Anatomy of the Hoof? What’s Going On In There?
The coffin bone, also known as the pedal bone, is the bottommost bone in the equine leg and is encased by the hoof capsule. Also known as the distal phalanx, third phalanx, or “P3”, the coffin bone meets the short pastern bone or second phalanx at the coffin joint.
The bones of the hoof are attached within the hooves of horses by layers of modified skin cells, known as laminae, which act as shock absorbers during locomotion. In horses, there are about 550–600 pairs of primary laminae, each with 150–200 secondary laminae projecting from their surface. The laminae connections hold the coffin bone suspended to the hoof wall, while the sole and frog support from the ground surface. The frog and digital cushion also absorb shock and together with the laminae they encase the coffin bone in a very strong elastic package.
What Happens When Laminitis Happens?
So, in layman’s terms, what happens when a horse gets laminitis? First off, any “–itis” suffix means simply “inflammation”. Not infection…that is something different, although the two are sometimes related and referred to in the same sentence. Inflammation can be classified as either acute or chronic. Acute inflammation is the initial response of the body to harmful stimuli and is achieved by the increased movement of plasma and white blood cells from the blood into the injured tissues. Prolonged inflammation, known as chronic inflammation, leads to a progressive shift in the type of cells present at the site of inflammation, and is characterized by simultaneous destruction and healing of the tissue from the inflammatory process.
Acute inflammation is characterized by “redness, heat, swelling and pain.” Acute inflammation is the body’s response to damage and doesn’t differentiate between an injury and the onset of laminitis, as you’ll see. This is one of the mysteries that researchers have been struggling with.
Acute inflammation is characterized by vascular changes, including vasodilation, increased permeability and increased blood flow. Vasodilation occurs first at the arteriole level, progressing to the capillary level, and brings about a net increase in the amount of blood present, causing redness (if it was outside the hoof capsule) and heat of inflammation. Increased permeability of the vessels results in the movement of plasma into the tissues, bringing white blood cells, proteins and antibodies. As this is happening, the swelling causes a restriction of blood flow and nutrients to the cells which leads to cellular death and further breakdown of the laminae. This function of bringing extra emergency healing fluid to the relatively rigid interior of the hoof capsule causes restricted swelling and subsequently causes pain. In fleshy tissue this swelling would be normal and controllable. Inside a hoof wall, it can be a catastrophe.
Because these connections were holding the coffin bone suspended to the hoof wall, this connection is now weakened and can stretch and tear. This forces the coffin bone, which is supporting the weight of the horse, to seek support elsewhere – from the ground surface directly below it. It can rotate or sink downward until it finds that support. It is when the coffin bone is supported by the hoof wall as the primary means of support that “founder” can happen. Picture a toilet plunger. When you put the plunger part on the ground and push on the handle, the center, which was previously held up by the periphery, looks for support from the ground directly below it. Same principle. If the hoof wall is long, the sole is concave, or if there are horseshoes suspending the front edge of the coffin bone, it can rotate or sink further, often through the sole.
How Could This Possibly Happen to My Horse?
So, how did this happen? What causes a horse to founder? Researchers wish there was a definitive answer, but in reality it can be a number of things singly or in combination. I’ve worked on national show horse winners right after a show. I’ve worked on expensive warmbloods and adopted mustangs each living in sandlots. I’ve worked on Budweiser Clydesdale broodmares in the perfect barn. All of them were a puzzle as to why laminitis happened, but it did. There are tons of articles written on laminitis causes and prevention so I won’t belabor that issue, but I’ll cover some obvious causes and shamelessly borrow as I try to simplify them. Wikipedia has tons of info. Also, there are at least four theories about the causes of laminitis. A few years back a virtual epidemic of laminitis in pregnant mares in Kentucky was a blamed on caterpillars. There are laminitis seminars and conferences every year to compare notes. So far, it’s still happening a lot.
The mechanism of laminitis remains unclear and is still the subject of much research. Three conditions are thought to cause secondary laminitis:
- Sepsis/endotoxemia or generalized inflammation
- Endocrinopathy (insulin related)
- Trauma: concussion or excessive weight-bearing
Inflammatory events that are associated with laminitis include sepsis, endotoxemia, retained placenta, carbohydrate overload (excessive grain or pasture), enterocolitis, pleuropneumonia, and contact with black walnut shavings. In these cases, there is an increase in blood flow to the hoof, bringing damaging substances and inflammatory cells into the hoof. Typically, there is a general body-wide inflammation caused by the release of endotoxins into the bloodstream; but which is more apparent in the hooves.
Endocrinopathy is usually the result of improper insulin regulation, and is most commonly seen with pituitary pars intermedia dysfunction (also called equine Cushing’s syndrome) and equine metabolic syndrome (EMS), as well as obesity and glucocorticoid administration. In cases of EMS, most episodes occur in the spring when the grass is lush, particularly when there is a freeze overnight and higher temperature during the day.
Mechanical laminitis starts when the hoof wall is pulled away from the bone or lost, as a result of external influences. Mechanical laminitis can occur when a horse habitually paws, is ridden or driven on hard surfaces (“road founder”), or in cases of excessive weight-bearing due to compensation for the opposing limb, a process called support limb laminitis. Support limb laminitis is most common in horses suffering from severe injury to one limb, such as fracture, resulting in a non-weight bearing state that forces them to take excessive load on the opposing limb (remember Barbaro?). This causes decreased blood flow to the cells, decreasing oxygen and nutrient delivery, and thus altering their metabolism which results in laminitis.
How to Tell If They Got It
So, how can you tell if your horse has laminitis? There are a few phases to laminitis. The first is the developmental/acute stage. This is generally within the first 1 to 72 hours. Clinical signs at this time include bounding digital pulses, lameness, hoof heat, and possibly response to hoof testing. The horse may have elevated temperatures and be sweating due to a body-wide inflammation. It may seem anxious and trembling. It may have the notorious “founder stance” of the front feet extended forward and the back legs underneath to take over more of the weight of the body from the sore front feet. It may want to lay down as often as possible. This is the most important phase where prompt and proper treatment can prevent displacement of the coffin bone. This information is covered below under treatments.
Chronic laminitis is when there is movement of the coffin bone within the hoof wall. A coffin bone can rotate downward due to the weight of the horse on the coffin bone no longer being securely suspended at the dorsal hoof wall. This can be combined with the tension of the flexor tendons which come around the Navicular bone and attach to the bottom rear of the coffin bone. A coffin bone can sink directly downwards as well. This is often signaled by a depression in the coronary band.
So What Can Be Done? Fix It!
The Laminitis Repair system has fixed many foundered horses world-wide both by myself or farriers and vets I coached. I have flown around the U.S. from Ocala to Malibu for what was normally a last chance for horses others gave up on. Many of these had the coffin bone protruding from the sole and the application of the prosthetics had them on their feet in minutes. See the testimonials for proof.
Contrary to some beliefs, a change of diet will not fix a structural catastrophe. Of course, the diet that caused laminitis must change right now. There are tons of diet recommendations out there but mainly, a fat horse has to lose weight. Plenty of low energy hay should be given and not much else. Supplements, herbal remedies, etc. are everyone’s separate opinion but, to be safe, fewer groceries are called for. Get the weight that’s on those sore hooves as minimal as possible during the healing process. Less weight equals less pain. OK, enough.
If a horse gets laminitis and there is no movement of the coffin bone, you don’t need my process. Just follow my trimming recommendations, chill the hooves with buckets of water, salt and ice, and the horse should recover. However, I’m basically an engineer and as this is a structural problem I work to fix that. However, the end result of the horse’s recovery may depend upon many factors, including the quality of aftercare, age of the horse, diet and nutrition, skill, and knowledge and ability of the attending veterinarian and farrier(s). Lack of these elements may lead to euthanasia of the patient. The only ones I’ve lost have been when the Laminitis Repair System was not kept up; hence, the Laminitis Repair Shop.
The first principle behind the Hoof Armor Laminitis Repair System lies in supporting the sole and suspending the hoof wall for as long as it takes to grow hoof wall back normally. In supporting the sole you are therefore supporting the forward edge of the coffin bone. Removing the pressure from the hoof wall by supporting the skeletal structure of the horse, and keeping the hoof wall trimmed so that it doesn’t contact the ground surface in normal movement will allow the hoof wall to grow out undistorted and attached via the laminae to the coffin bone in a normal manner and with a thicker sole grown under the coffin bone. In effect, de-rotating the coffin bone. This has been proven on x-rays.
Think of the hoof like your fingernail. If you caught your fingernail on something and it tore away from the nail bed it would hurt. Or, maybe got your finger smashed and the nail detached from the nail bed. As long as you kept upward pressure on it, it will keep hurting and it will never grow back reattached. Only when you take the pressure off is the nail able to grow back reattached. The hoof is the horse’s nail and the function is the same. Take the pressure off of the hoof wall and let it grow back reattached. You’ve seen chronic laminitis where the hoof tried to grow back under pressure. That’s what causes the laminar wedge that blocks regrowth.
The second principle of the Laminitis Repair System involves very slightly elevating the heels. This allows the flexor tendon attached to the bottom rear of the coffin bone to relax. This tension can cause a downward pull on the coffin bone and further contribute to the rotation effect. By raising the heels the form puts slight pressure on the extensor tendon which is attached to the top front of the coffin bone and will put pressure toward maintaining the coffin bone as it is drawn toward its original position.
The Hoof Armor Laminitis Repair System fabricates a rigid form molded precisely to the bottom of the hoof covering the sole and frog and staying inside the hoof wall. The sole pressure is distributed 100% over the entire sole and frog and therefore does not put pressure in any one area. The bottom of the form is lens shaped for easy break-over and thick enough to keep the hoof wall from contacting the ground surface. The lens shape of the form also allows the horse to find its most comfortable position. The rear of the form is thicker to elevate the heels a little higher than normal to utilize the tendons.
The treatment must be continued for as long as it takes for the hoof wall to grow back reattached to the coffin bone, while the sole grows thicker for more coffin bone support. The sooner treatment is started following the onset of laminitis or founder the quicker the recovery will be. For example, the approximate time for an entire hoof to grow out is one year. If the hoof is chronically distorted and separated halfway up it will take about six months to recover. This means that the form must remain on the hoof continually for that length of time, except for periodic removal and replacement for cleaning, disinfecting and maybe refitting. This should be done as often as necessary, sometimes several times a day. The form should be removed and the hoof wall trimmed back as often as necessary to avoid ground pressure on the wall.
And abscesses…yes, they are a routine part of laminitis recovery. As the hoof grows back the excess fluids that filled the expanded space must come out. It is a function of recovery. The exudate materials are too large to be passed through the bloodstream, so they work their way out wherever it is soft enough. The forms should be removed daily and the abscesses cleaned. They are not infectious abscesses, but must be disinfected and the hoof form reinstalled or refitted as necessary. That is a prime reason for Laminitis Repair Shops where daily professional care can be maintained so the recovery progress remains on the fast-track.