Saturday, June 15, 2013

Horses: Grass Founder

To protect your horse's health, you may need to limit his access to sugar-rich grass.

Why? Well, because lush spring pastures can be dangerous temptations for horses.

Especially during Spring, lush green grass begins to grow, it could be the beginning of serious founder problems – laminitis.

Laminitis is inflammation of the laminae of the horse’s foot.

the normal hoof

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.

foundered hoof with rotated coffin bone

Laminitis is a word no horse owner wants to hear associated with her horse.

It is a crippling disorder that takes weeks or even months for the horse to recover from, and that is if all causative factors are removed and the best equine husbandry is provided.

It can be permanently debilitating if not dealt with properly and promptly, leading to much pain and suffering for the horse.

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 repeated concussion on hard ground (road founder); grain overload; retained placenta; hormonal imbalance (Cushing’s disease or metabolic syndrome); certain drugs (corticosteroids); obesity; and lush grass.

Veterinarians and nutritionists have known for some time that plants store energy in their seeds in the form of starch that can cause laminitis if the horse is introduced to grain too quickly or eats 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.

Here are some tips for avoiding grass founder:

• 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 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.

• Allow horses to fill up on hay before turning them out on grass for a few hours.

At Risk

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.

If you have horses that are prone to grass founder, visit with your veterinarian or equine nutritionist to develop a strategy for introducing them to spring grass.

This is truly a situation where an ounce of prevention is worth a pound of cure.

Laminitis vs. Founder

What is the difference between acute laminitis and chronic laminitis, or founder?

If my horse has laminitis, does that mean he has foundered?

The term laminitis is often used interchangeably with founder, but technically the two are different, though related, phenomenon.

Laminitis is inflammation of the laminae in the hoof.

The laminae are the velcro-like connections that attach the coffin bone to the inner hoof wall, holding the foot together; because the laminae are trapped between a rock (the coffin bone) and a hard place (the inner hoof wall and sole), any inflammation is painful for the horse.

Chronic inflammation over time, or a catastrophic laminitis episode, will lead to degeneration of the blood vessels that feed the laminae and necrosis of the laminae themselves.

This breakdown of the laminae results in the coffin bone separating from the hoof wall and “rotating”; this stage of laminitis is properly called founder.

In very advanced cases of founder, it is possible for the entire hoof to slough off, or the coffin bone to penetrate the sole.

Acute laminitis usually lasts for only a few days.

External causes, like concussion on hard footing (commonly called “road founder”), chemicals like nitrate fertilizer, infections, colitis, pneumonia or retained placenta in a mare can all cause laminitis.

But those cases often heal and don’t result in chronic laminitis. A horse can have laminitis, heal and not founder.

When the laminae in the foot become so inflamed and damaged that they no longer support the coffin bone, which then rotates and sinks, the condition is then called chronic laminitis or founder.

That is when a long-term maintenance program provides the best possible outcome for the horse living with laminitis.

The signs

The signs can be subtle and confused for something else, like laziness, muscle soreness or arthritis.

Remember, laminitis is usually associated with the horse not wanting to bear weight on the front hooves and rocking his weight back on his haunches.

Not only do the hooves hurt terribly, but this posture quickly becomes painful as well; the horse was designed to bear more standing weight on the forelimbs, and extended periods of weight bearing on the hindquarters stress the joints and create chronic muscle tension.

What isn’t as well recognized is that there are usually early warning signs that a horse is developing laminitis; unless the horse broke into a fifty pound bag of grain, most cases develop over a few days, weeks, or even months.

For example, in early stage laminitis, a good footed horse will start to mince on gravel and walk slowly on concrete for no apparent reason.

A horse with a Grand Prix trot may begin to shuffle like a peanut-rolling pleasure horse.

Another horse may not want to pivot on his front feet.

A horse that would normally race out to pasture now walks or jogs.

While many laminitic horses exhibit the classic signs of heat in the feet and a bounding digital pulse, there are some horses, and especially early stage laminitics, that don’t present these symptoms.

Things to remember

Most laminitis cases are preventable, as they are related to the horse’s diet. Grain overload and too much pasture are very common culprits.

Most all grain products are very high in sugar content, and pasture can fluctuate from moderate to high sugar levels.

This leads to the reason for writing this article at this time of year; many horse owners realize the potential for grass founder in the spring, but don’t know that fall grasses can be just as problematic, as the climatic conditions that produce such rich forage are basically identical in spring and fall.

What is even less known is that some hays may be causing laminitis problems as well, as many of the hays commonly available have been hybridized for maximum sugar content to meet the demands of the dairy industry.

Horse owners wanting to understand the effects of sugar on the horse’s metabolism and how difficult it is to predict sugar content in a particular grass or hay should understand that whether its from grain, grass or hay, this diet rich in sugar triggers the inflammation, and therefore pain, in the hoof.

Other laminitis triggers are not quite as obvious.

Some horses react to certain medications, vaccines and wormers.

Infectious diseases or a retained placenta are also possible causes.

Metabolic disorders such as Cushing’s and insulin resistance can cause chronic laminitis and can be particularly difficult to treat.

And laminitis is not just for obese horses. While obesity may make a particular horse an easier target for a laminitis attack, a thin horse can still be susceptible.

If your horse is suddenly moving differently, and there’s no evidence of injury, take note of what may have changed in the last few weeks.

Is she being fed a different hay?

Has she been put out on pasture?

Has there been any other change in the feeding routine?

Have any medications been administered?

Provide this information to your veterinarian, as these may be clues that the horse is dealing with laminitis.

If laminitis is suspected, contact your veterinarian immediately, remove any identifiable triggers, and make sure the horse is transitioned to a low sugar diet.
An ounce of prevention goes a long way, attacking laminitis before it gets a foothold will save a lot of agony for horse and owner.

Every day veterinarians across the country see hundreds of cases of laminitis, a painful disease which affects the horse's feet.

What's especially alarming is that some cases are preventable. In fact, it may be that we are killing our horses with kindness.

Consider that a common cause of laminitis is overfeeding, a management factor that is normally within our control.

By learning more about laminitis, its causes, signs and treatments, we may be able to minimize the risks of laminitis in your horse, or control the long-term damage if it does occur.


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