Founder and the Horse


Spring is upon us. As our green grass begins to grow, it could signal the beginning of serious founder problems – laminitis.
Laminitis is inflammation of the laminae of the horse’s foot. Laminae make up the delicate, accordion-like tissue that attaches the inner surface of the hoof wall to the coffin bone (the bone in the foot.) The sensitive laminae cover the bone and interlock with the insensitive laminae lining the inside of the hoof wall to keep the coffin bone in place within the hoof.
A horse suffering from laminitis experiences a decrease in blood flow to the laminae, which in turn begin to die and separate. The final result is hoof wall separation, rotation of the coffin bone and extreme pain. In severe cases, the coffin bone can actually rotate through the sole of the horse’s hoof where it becomes infected and usually results in the death of the horse.
Laminitis is triggered by a variety of causes, including lush grass, repeated concussion on hard ground (road or mechanical founder); grain overload; retained placenta; stress, hormonal imbalance (Cushing’s disease or metabolic syndrome) and certain drugs (corticosteroids). Obesity makes any of these much more likely to happen.
Veterinarians and nutritionists have known for some time that plants store energy in their seeds in the form of starch that can cause laminitis. This is why a horse must not be introduced to grain too quickly or eat too much grain. Only recently have researchers discovered that grasses not only store energy in their seed heads as starch, they also store energy as sugar.
In the spring, as grass is growing rapidly, it stores more sugar than it needs for growth, and horses consume the sugar as they graze. Later in the year, when the daylight and nighttime temperatures are more consistent and grass growth rates decrease, the plant uses up most of the sugar produced during the day each night.

We OFTEN hear, “but horses in the wild eat grass all they want and they are fine!” Yes, because humans have not used fertilizer to kill all the weeds in their lands and thickened the grass. Because humans have not fenced them in and provided them with easy access to water where they never have to roam far and exercise when they are thirsty. Our “un-natural” horse keeping is what has created this problem and many others!

Here are some tips for avoiding grass founder:
ALLOW HORSES TO FILL UP ON HAY BEFORE TURNING THEM OUT ON GRASS FOR A FEW HOURS. This one is a very important, easy step. When turning horses out onto lush pasture (or onto pasture for the first time if they have been completely stalled), limit their grazing time for several days to avoid digestive upset and laminitis. Increase the amount of turnout time by one hour every 3 days until they’re turned out for the desired time (be it all the time or just until they’re brought in for the night).
Make sure your horses get at least 15 minutes of good exercise per day. This should include some trotting. Round penning them or riding them is ideal.
Watch what kind of grain you are feeding at the same time as lush grass. A grain based, low NSC grain is best if it is needed at all.
Keep horses off lush, fast-growing pastures until the grass has slowed in growth and produces seed heads.
Graze horses on pastures containing a high percentage of legumes. Legumes, such as alfalfa or clover, store energy as starch, not sugar.
Avoid grazing horses on pastures that have been exposed to bright sunny days followed by low temperatures, such as a few days of warm sunny weather followed by a late spring frost.
Avoid grazing horses on pastures that have been grazed very short during the winter and are growing rapidly.
Keep overweight horses in stalls or paddocks or put a grazing muzzle on them until the pasture’s rate of growth has slowed, then introduce them to pasture slowly.
Turn horses out on pasture for a few hours in the early morning when sugar levels are low, not at night when levels are at their highest.
To avoid being unnecessarily cruel, you MUST take all precautions to keep this from ever happening again! IT IS VERY VERY PAINFUL TO YOUR HORSE TO BE IN THIS STATE!!!!!!
Horses that are over the age of 10, “easy keepers,” overweight or those with crested necks seem especially vulnerable to grass founder and should be the focus of your preventive program.
After the horses are turned out on pasture, check them often for early signs of laminitis such as heat in the feet and a pounding pulse at the back of the pastern. Foundered horses also assume a characteristic “sawhorse” stance with their hind feet up under their body and their front feet placed farther forward than normal. This is because the horse is trying to shift its weight off its painful front feet to its hind legs.
Grass-foundered horses also move gingerly, as if walking on eggshells, and are often unwilling to turn or move at all. In severe cases, the horse may refuse to stand. If your horse demonstrates these signs after being turned out on grass, immediately pull him off the pasture and call a veterinarian. While you are waiting for their arrival, you can cold hose the feet, or stand them in a creek, puddle, or wet mud. These things will give your horse a bit of relief.
Buttercup is pictured here in a classical founder stance. She was an owner surrender when her person realized she needed more help than she was able to give. Butter will always have to be managed carefully to avoid another painful episode.

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