Last Updated on February 28, 2022 by Allison Price
Laminitis can be fatal. Learn why this deadly disease is so dangerous and what you can do to prevent your horse falling prey.
I love horses. As an equine veterinarian, it is one of my greatest acts of kindness to end the suffering of horses with severe laminitis. My fellow equine vets also endanger many horses every year because of the same reason.
Laminitis, also called founder, is able to strike any horse. Remember Secretariat? Remember Secretariat? He was 19 when he contracted laminitis and had to be put down. Barbaro was born. He became a household name after fracturing his left leg in the Preakness Stakes 2006. We all saw the reports about the many surgeries and intensive care he received over the next 8 months. He eventually found himself in serious pain and was eventually euthanized. Gunner, the beloved reining horse and sire of Gunner, was euthanized last summer. This disease caused Colonels Smokin Gun to be put down.
Laminitis is a deadly disease. How is it possible that horses as valued and well-cared for as Secretariat and Barbaro can’t withstand it?
It’s all about the discomfort. We’ll be looking at the function of your horse’s feet and the physical damage that can occur when it gets laminitis. This article will help you understand the causes of laminitis and how to stop it from happening again. We will discuss the causes, risk factors, and triggers of laminitis. And, last but not least, we’ll show you how to prevent your horse from becoming a victim. –
From Bad to Worse
Your horse’s foot is unique. The foot allows a horse weighing 1,000 pounds to run, jump, and slide on his tips. Prey animals are horses, which means that they evolved to run fast across the ground and avoid predators. He evolved from a tiny, fawn-like creature to become the long-legged, sleek animal we see today. He was able to use his middle toe to support himself, and his legs became longer to be faster and more efficient.
The hoof is a hard, horny structure covering and protecting the bones and soft tissue of the foot. The hoof’s inner surface is composed of 600 serrated ridges called the “insensitive lamellae.” Each ridge appears a bit like a grapefruit knife blade, with 150 to 200 secondary ridges running along each primary lamella.
The tissue covering his lower leg’s bones has 600 projections of fleshy finger-like tissue. These are called the “sensitive lamellae.” Each sensitive lamella also has 150 to 200 secondary ridges. These secondary and primary lamellae form the bond that holds your horse’s hoof together. This bond must be strong enough to withstand the weight of your horse, as well as his jumping and running.
Each secondary insensitive lamellae has a rounded tip that is enclosed by a “basement Membrane” which separates it from adjacent sensitive lamellae. Laminitis is a condition in which the relationship between the cells at each lamella’s tip and the cells of their basement membrane breaks down. This can be divided into three grades.
Grade 1 –Tips containing secondary insensitive lamellae get elongated and lose contact with basement membrane. Small bubbles can be seen at the tips of secondary insensitive lamellae, where they no longer attach to the basement membrane. This is before symptoms appear. This means that your horse’s feet will be damaged before you notice any symptoms.
As seen here, the coffin bone of a horse is aligned with the hoof wall. The lamellar attachments can become weaker and separate from each other during laminitis. This allows the toe of a coffin bone or the whole coffin bone, to turn downwards, causing a lot of pain.
The coffin bone is held in place by the interlocking mechanism formed by the sensitive and insensitive lamellae. These lamellae become dislocated during laminitis.
Grade 2 With each step taken by your horse, the cells of its lamellae move closer to the basement membrane. The connective tissue between secondary lamellae and the cells that make up these layers is being ripped away as they separate. As they come into contact with each other at the base, the insensitive lamellae lose “holding power”, instead of securing themselves to the fleshy fingers of sensitive lamellae. Small blood vessels, called capillaries, are also drawn away by the lamellae’s cells. This causes increased resistance to blood flow. This is why your horse may feel a “pounding” or strong pulse in his feet when he first develops laminitis. It’s a sign that usually comes with the onset and progression of pain. What does this signify? This means that the link between your horse’s hooves, and his feet, is already potentially irreversible.
Grade 3 This is the final stage in laminitis. It involves the complete separation of the basement membrane and the lamellae. This separation can initially be only seen under a microscope. As it progresses, you can see the horse’s bones and soft tissue separated from the hoof. Within the hoof capsule, the toe of the horse’s hoof-shaped coffin bone begins to rotate (or “sink”) into its hoof. It will sink straight down in severe cases where all attachments have been lost. This is known as the “fatal sinker syndrome”, which is the most severe form of laminitis. The horse has lost all attachments to his hooves. Grade 3 laminitis may occur abruptly (complete separation can occur as soon as 48 hours after the process began), or slowly over time. The pain can be excruciating and constant in either case. Grade 3 laminitis can be fatal if euthanasia is the only option for horse relief.
What Causes Laminitis?
There are three main mechanisms that can cause laminitis episodes: hormonal disorders and intestinal disturbance. This is how it works.
Hormonal Disorders:It all comes down to insulin, which is responsible for controlling glucose (sugar metabolism). Laminitis can be caused by insulin resistance (IR). Insulin is released when glucose enters the horse’s bloodstream to stimulate glucose uptake into his tissues for storage and processing. Insulin is also involved in controlling blood flow by dilation of blood vessels. Insulin resistance means that your horse’s insulin is less effective and blood flow through his feet is affected.
Equine Metabolic syndrome is a condition that can lead to insulin resistance. Your horse may be overweight with fat deposits around his head and crest, and an easy-to-keep horse who thrives on air. Obesity, grain overload (your horse sneaks into a feed room), and grazing on lush green pasture grass pose major laminitis risk factors. They increase glucose in your horse’s bloodstream, cause excessive insulin release, and eventually lead to insulin resistance.
Cushing’s disease, another hormonal condition that can cause laminitis indirectly through its effects on insulin, is also known. Cushing’s disease can cause abnormal pituitary function in horses with Cushing’s disease. This causes an increase in cortisol, the body’s stress hormone, to be released into your horse’s system. While the exact link between cortisol, laminitis and insulin is not clear, it is believed that cortisol may antagonize the effects of insulin–which could again compromise blood flow to your horse’s feet. Cushing’s may not increase your horse’s likelihood of developing laminitis. Cushing’s can increase your horse’s risk of developing metabolic syndrome. This is when laminitis occurs most often.
Intestinal disturbances: If your horse experiences severe colic or diarrhea, his normal bacteria population that helps maintain the intestinal balance can become depleted. Acid levels rise and the horse’s intestines become less able to absorb nutrients, which allows toxins and other inflammatory cells to get into his bloodstream. This combination of bacterial byproducts and inflammatory cells causes blood vessels to narrow, reducing blood flow to his feet.
Carbohydrate overload, whether it is from an over-indulgent snack or an overnight attack on the feedroom, can cause intestinal disruption and impact insulin. Double-whammy effects may explain why laminitis caused by carbohydrate overload can be sudden and severe.
Mechanical: If your horse is injured, his lamellae may become damaged. This can lead to a long-lasting, but often irreversible, episode of laminitis. This type of laminitis was evident in Barbaro’s death. Barbaro’s death was caused by the stress of weight bearing on his “good” leg during treatment for his fracture. This left him literally with no leg to stand on.
Mechanical stress can also be caused by long, hard, on-the-ground work (“road founder”) or poor farrier care that causes chronic foot imbalance. If your horse is prone to having very long toes and low heels, this can cause laminitis.
Prevent Laminitis from Taking Your Horse
Laminitis is a deadly disease. Why is it so difficult to treat? It’s all about pain, the constant, excruciating suffering. You should also consider the fact that irreversible damages can often occur long before signs are identified. This means that no single treatment will always be effective. It is easy to see how laminitis can cause so much suffering in horses. Prevention is key. These are the five steps you should take.
It is important to recognize it quickly. The damage starts before your horse becomes lame. It’s important to identify subtle signs of laminitis early so that you can start treatment. Your vet should be notified immediately if your horse has a foot sore or digital pulse. Research has shown that applying cold to the feet can prevent basement membrane from separating. This happens before the lamellae loose their grip. This is why icing can be very effective in preventing the disease from progressing early. Put buckets of ice water on your horse and ask your vet for advice regarding administering anti-inflammatory drugs such as flunixin meglumine or bute. You should avoid exercising if you suspect you have laminitis. Exercise can add stress to the lamellae and make things worse. Do not walk your horse and do not turn him around.
Research shows that laminitis is most common in those who are older. You can’t stop the aging process, but you can pay special attention to your older horse.
Be aware of your body weight. Another important risk factor for laminitis is body weight. Don’t let your horse get fat. Obese horses are more likely to develop insulin resistance and laminitis. His weight alone can cause mechanical stress to the lamellae. You can protect your horse by keeping him at a healthy weight. To keep your horse fit, adjust his rations and ensure that he is on an exercise program.
Avoid carbohydrate overeating. Even if your horse isn’t overweight, his overnight consumption of grain or sudden exposure to lush green pasture could lead to a laminitis episode. Close feed-room doors and lock grain bins. Your vet should be contacted immediately if your horse gets into the grain room. If your horse hasn’t been outside in a while, gradually introduce pasture-grass exposure to him. Avoid free-choice green pastures if your horse is older, obese, or has insulin resistance. He can be allowed to graze on pasture with a properly fitted grazing muzzle.
Cushing’s disease can be diagnosed and treated. Consider testing your horse if you suspect that your horse may be suffering from Cushing’s disease. Cushing’s disease can be treated if it is diagnosed. The TRH stimulation test is a more sensitive test that can detect this disease early. If your horse is symptomatic and tests negative, ask your vet if this test would be recommended to identify Cushing’s disease early.
Take care of your horse’s feet. Avoid mechanical trauma to his lamellae. Pay attention to the surface where your horse works and maintain a consistent trimming or shoeing schedule. A radiograph of your horse’s feet might be recommended by his vet or farrier to show the relationship between his coffin bone and his hoof wall. Regular radiographs at 6- to 12-month intervals will allow his hoof-care provider to have the best chance of keeping his feet in balance. Radiographs are valuable for all horses, but they could save the life of a horse that is prone to laminitis.
