Fall Laminitis in Horses

 

 

How Grass Affects the Laminae in the Hoof

 

• You may hear the phrase “sugar goes right to their feet,” and in many ways, that’s absolutely correct. But how do we get from a horse grazing on pasture grass to laminitis?

 

Sugary pasture and the microbes of the cecum trigger damage

 

• The intestinal microbes aid digestion when sugars and starches enter the horse’s hindgut. Some microbes break down fiber; others work on sugars and starches. Ideally, the horse’s small intestine digests the sugars and starches, leaving very little to journey into the hindgut.

 

• When horses overeat sugar, the small intestine has leftovers, thus feeding the microbes in the cecum this excess sugar content. When in large enough quantities, this microbe feast changes the pH of the hindgut, killing some of the other microbes.

 

• Then, there is a change in pH, endotoxins are released as microbes die, and the intestinal wall will leak this toxic brew into the bloodstream. From here, those endotoxins float through your horse and trigger an inflammatory response, affecting the hoof’s laminae. And BAM – laminitis.

 

• Another byproduct of this process is gas, which can trigger gas colic and painful torsions of the digestive system.

 

For more on hoof anatomy, this article is for you!

Read this for deets on the horse’s digestive system.

 

    

This x-ray shows the coffin bone’s normal position inside this hoof.  

 

How does laminitis turn into autumn founder?

 

• When the inflammation is severe enough, the blood flow to the horse’s hoof is severely compromised. The damaged laminae, which once held the coffin bone in place, starts to falter due to the swelling and decreased circulation.

 

• The tendons of the lower leg also play a role in founder. The deep digital flexor tendon (DDFT) attaches to the underside of the coffin bone. In a healthy hoof, this tendon aids movement by pulling the hoof from the bottom. It’s primary role is to flex the leg, but it also supports the heel.

 

• As the laminae fail, the usual tension in the DDFT tugs at the coffin bone and, without much resistance, can create rotation and sinking of the bones. Unfortunately, this structural failure can lead the bone to punch through the sole of the hoof.

 

• Equine laminitis does not always end in founder, but a foundered horse will suffer greatly and have a much longer recovery process. This underscores the value of early intervention and help from your vet.

 

 

Grass may look dead or dormant, but it’s still stocking up on sugars. 

 

Risk Factors for Fall Laminitis and Founder

 

• There are two main reasons the risk of fall laminitis is greater than spring laminitis. One, your horse’s metabolism fluctuates in the fall, and two, changing weather creates grass that hoards sugars.

 

• Incidentally, the #1 reason horses develop laminitis is due to metabolic disorders. This creates endocrinopathic laminitis, which is the vast majority of cases.

 

Metabolic Health

 

• During this time of year, your horse’s brain is preparing their body for winter. As their eyes notice daylight hours dwindling, they grow a winter coat.

 

• Fall also signals your horse to gain weight to prepare for colder weather. As the seasons change, their pituitary gland releases more adrenocorticotropic hormone (ACTH) to signal hair growth and weight gain. ACTH is also involved in a chain reaction of hormones – by increasing cortisol, the stress hormone, and eventually down the line to rising insulin levels.

 

The trouble with insulin

 

• There is a direct link between increased insulin levels and an increased risk of laminitis. In research programs, laminitis in horses is triggered when horses are dosed with insulin.

 

• While helpful in the winter, as insulin reminds your horse to conserve energy and keep their fat reserves, it may also create laminitis.

 

• This article from an equine nutritionist expands on fluctuating hormones and metabolic conditions in equines. 

 

Simple bloodwork can help you determine your horse’s metabolic status. 

 

EMS influences hormonal changes

 

• Equine metabolic syndrome (EMS) is an endocrine system disorder that appears in a few ways. Horses with EMS:

 

• Display weight issues – they are overweight or have weird pockets of fat in places like the crest, shoulder, or flank.

 

• They have insulin dysregulation, usually called insulin resistance (IR). IR means that your horse will produce insulin, but their body doesn’t react to it as it should, so more is made. In human terms, this is very similar to pre-diabetes.

 

• Have had laminitis, have subclinical laminitis, or have chronic laminitis. A horse may have had a solitary instance of laminitis, or they show very mild signs but have hoof damage, or they are always coping with signs of hoof pain.

 

Read more about subclinical, acute, and chronic laminitis here.

 

Overweight horses are at risk of EMS and Osteoarthritis

 

• Monitoring your horse’s weight is always a good idea, as overweight horses commonly develop EMS. Additionally, that extra weight exacerbates osteoarthritis in their joints, reducing mobility and comfort.

 

PPID (Cushing’s disease)

 

• Pituitary Pars Intermedia Dysfunction (PPID) in horses begins in the brain. Damaged neurons deep in the hypothalamus affect part of the pituitary gland, causing it to produce more ACTH than is necessary.

 

• And that ACTH and subsequent cortisol increase creates muscle wasting, excessive hair growth, and increased insulin levels.

 

• In a nutshell, EMS and PPID cause increased insulin secretion. When the horse’s body nears winter, this makes the insulin levels that much higher.

 

ICE ICE ICE ICE ICE if you even suspect laminitis.

 

Pasture Conditions

 

• Fall’s weather can sometimes be a guessing game, with wild swings of temperature and rain. Many factors increase sugar and starch levels in the grass:

 

• Chilly nights and cooler early morning temps create sugar spikes. 
• Warm afternoons also create sugar spikes.
• Mowing can increase sugars, too.
• Grass going to seed requires hoarding sugars and starches to reproduce
• Late summer rains can trigger a growth spurt of grass, not unlike that in the spring. 

 

• You may not see the wild growth and bright color change of pasture that you do in the spring, but know that the grass is much sweeter and not always in a good way.

 

When you consider those hormones and the unique sugar-hoarding habits of grass in the fall, the overall risk of laminitis and founder increases for all horses, but horses with metabolic disorders have a double whammy.

 

 

Reduce the Risk of Fall Founder and Subsequent Lameness

 

• You can reduce the likelihood of acute laminitis in three primary places in the fall. One, know your horse’s metabolic health status; two, feed your horse a low-sugar and starch diet. Lastly, make barn management and lifestyle changes that encourage a healthy body weight, movement, and slow feeding.

 

Your vet can test for many metabolic conditions

 

• Your vet can use several blood tests to uncover EMS and PPID. Usually, it’s a simple blood test, but the timing of the test does matter. Your vet can help you decide what tests are best, and when to perform them.

 

• Because the window of increased ACTH ranges from July to November, it might mean your vet pops over in the summer, or for other horses, later works well, too.

 

• If your horse is already overweight or has a history of hoof soreness, consider testing as soon as possible to get some baseline measures that can be monitored all year.

 

Equine Nutrition Considerations – Forage and Supplements

 

• Feed a low non-structural carbohydrate (NSC) value diet. Ideally, your horse’s forage and commercial feeds, grains, and supplements all have NSC values under 10% if there is a metabolic disease. However, this lower NSC value benefits all horses.

 

• NSC value measures the sugars and starches in the equine diet.

 

• Use hindgut buffers. This supplement will help balance the hindgut’s pH should there be too much sugary deliciousness in your horse’s hindgut. Hindgut buffers also support general digestive health.

 

• Use an Omega-3 fatty acid supplement. Omega 3’s are anti-inflammatory, support skin and coat health, taste great, and some even include gut health support, like pro- and pre-biotics. Flax seed is affordable and delicious.

 

 

The Benefits of Slow Feeders and Grazing Muzzles in Autumn

 

• While NSC values are one portion of the equine nutrition plan, all forage and feed are best when “meals” are avoided and your horse nibbles on feeds all day.

 

Slow feeding accomplishes many things:

 

• Your horse is chewing and occupied for most of the day.

 

• Gastric ulcer risk is reduced.

 

• They are mimicking natural feeding behaviors.

 

• Less sugar and starch are entering the cecum, and the volume matters; just ask the clever horses that break into the feed room.

 

Slow feeder systems

 

• There are dozens of slow-feeding systems for hay and forages – tubs, nets, bags, and toys.

 

• You can also find specialty tubs and bowls for commercial feeds.

 

• For pasture grazing, opt for grazing muzzles. These wearable hay nets reduce the volume of food and reduce the speed at which sugars and starches enter the hindgut. It’s a win-win for overweight and metabolic equines.

 

• Grazing muzzles also allow turnout, movement, and herd interactions.

 

• Slow feeding is beneficial year-round, and it’s extra important to help prevent fall laminitis.

 

Omega 3’s are easy to feed.  Flax is affordable and delicious and an excellent source of Omega-3’s.

 

Lifestyle changes and overall health considerations

 

• Keep your horse moving. Regular exercise and turnout are keys to healthy and happy equine partners. 

 

• Monitor your horse’s weight. A simple weight tape measurement every few weeks tells you how your horse’s weight trends. 

 

• Use dry lots when needed. These are a great alternative when the pasture has reached peak sugar content.

 

• Know how to check your horse’s digital pulse, and do so daily. This handy and super-quick measurement of the blood flow into the hoof alerts you to possible hoof danger long before your horse shows classic signs of laminitis, like reluctance to turn and awkward stances.

 

Read about checking your horse’s weight here.

This article describes checking the digital pulse.

 

A weight tape is a must-have to monitor your horse’s health. 

 

Your Veterinarian and Farrier Can Help Stop Horse Founder in the Fall

 

• Your vet and farrier are a team when it comes to hoof health. At the first sign of any hoof problem, talk to your vet. Only they can x-ray, diagnose, relieve pain, and create a treatment plan for hoof trouble.

 

• Your farrier then helps execute said plan, which might be as simple as creating a channel for an abscess or special trimming and shoeing for laminitis cases. Farrier care is also ongoing and critical for chronic laminitis cases.

 

What are the symptoms of fall laminitis in horses and ponies?

 

• Symptoms of fall laminitis in equines include lameness, increased digital pulse in the hoof, shifting weight between hooves, reluctance to move, heat in the hooves, and a stretched stance to relieve pain. Monitoring these signs and seeking veterinary care promptly for proper treatment is crucial.

 

What are the effects of horse founder in the fall?

 

• Recurrent fall laminitis in horses can lead to chronic lameness and hoof deformities and even necessitate euthanasia in severe cases. Prevention is best, using proper barn management protocols, low NSC value diets, weight management, and regular vet care to check for equine metabolic disorders.

 

What’s the prognosis for horses with fall laminitis?

 

• Horses that have experienced fall laminitis have a guarded prognosis. Early detection and prompt treatment are crucial for a better outcome, including ice therapy, calling your vet immediately, and changing your horse’s diet. Your vet and farrier will need to monitor your horse continuously to prevent further damage, like founder, from fall laminitis.

 

The following comes from the Equine Cushing’s and Insulin Resistance Group, Inc, (ECIR) 

 

• Research has shown, and most veterinarians recognize, that most laminitis cases are related to hormonal/endocrine disorders, specifically those involving insulin resistance. Avoidance requires diets very low in simple sugars (ESC) and starch, i.e., the components of the diet which cause an insulin rise (fructans do not elevate insulin).

 

• While it’s true that regrowth of fall pastures and/or exposure to cold nights can raise the simple sugar and starch levels in the grass, fall laminitis can, and often does, strike horses that had no trouble handling spring pastures and even many horses with no access to pasture at all.

 

• Eleanor Kellon, VMD, Veterinary Advisor to ECIR Group Inc, explains. “The typical case of fall laminitis is experiencing laminitis for the first time, or as a repeat of a previous fall episode. They are in their teens (or occasionally older) and owners report no change in diet or management. The cause is the seasonal rise in the hormone ACTH.”

 

Grazing muzzles help reduce the risk of laminitis.

 

• ACTH is a hormone secreted by the pituitary gland. Its function is to stimulate the adrenals to release cortisol. Cortisol induces insulin resistance and also makes the blood vessels in the hoof more sensitive to chemicals mediating constriction. “All horses experience this seasonal rise in ACTH“, said Kellon, “but it can be much more pronounced in older horses, particularly those in the early stages of PPID (pituitary pars intermedia dysfunction – Cushing’s disease) which may not yet be showing any obvious outward symptoms.”

 

• The ECIR group has been following horses with hormonal disorders for over 15 years. In that time we have seen many horses whose first sign of PPID was an episode of fall laminitis. If your horse experiences this, have a talk with your veterinarian about testing for ACTH and PPID. The usual dietary measures are not enough when high levels of ACTH are involved. These horses require therapy with pergolide.

More about the ECIR Group, Inc.

 

• Started in 1999, the ECIR Group is the largest field-trial database for PPID and IR in the world and provides the latest research, diagnosis, and treatment information, in addition to dietary recommendations for horses with these conditions. Even universities do not and cannot compile and follow long term as many in-depth case histories of PPID/IR horses as the ECIR Group. In 2013 the Equine Cushing’s and Insulin Resistance Group Inc., an Arizona nonprofit corporation, was approved as a 501(c)3 public charity. Tax-deductible contributions and grants support ongoing research, education, and awareness of Equine Cushing’s Disease/PPID and Insulin Resistance.

 

• For more information on the seasonal rise in ACTH, Cushing’s Disease and insulin resistance in horses visit www.ecirhorse.org and our outreach group at https://ecir.groups.io/g/main.

 

 

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