Here is one of the two muscles we’ll focus on: the longissimus dorsi, which both extends the horse’s back and flexes his spine laterally.

Photos © Jim Leiby

How do you feel and behave when you get out of bed in the morning with tight or painful back muscles? Chances are you move stiffly or tentatively and your range of motion is restricted. Until you get relief, you don’t have your usual enthusiasm for normal tasks.

It’s much the same for your horse when his back muscles are stiff or hurting. He may

• flinch or sink away when you’re saddling him;
• travel with his head elevated and/or his back hollowed;
• canter less freely than usual;
• experience a decrease in coordinated power;
• trail his hind end rather than stepping under himself;
• jump flat rather than with a rounded bascule;
• drift sideways, either on the flat or over jumps;
• resist lateral work.

One thing your horse will not do as a response to back pain or tightness, by the way, is buck. He needs to round or flex his back to buck, whereas his normal reaction to pain and tightness in his back is to move away from the discomfort by hollowing.

What’s Hurting

The longissimus costarum, just below the longissimus dorsi, extends across the horse’s ribs. This muscle assists in extending the spine and in flexing it laterally.

© Jim Leiby

The muscles whose tightness is frequently a cause of these signs are the longissimus dorsi—the longest and largest muscles in your horse’s body and a powerful extensor of his spine—and the longissimus costarum, which lie below the longissimus dorsi across the ribs on each side and are important in lateral flexion of the spine and in breathing (see photos page 66 for the location of these muscles).

As part of understanding how tightness develops in these and other muscles, let’s take a quick look at how muscles work. Every muscle has two ends, each connected to bone by a tendon. One end is the anchor and the bone to which it is connected doesn’t move. The other end is connected to a bone that moves when the muscle is used. The middle part of the muscle, which does the work of moving the bone, is called the belly. It’s composed of hundreds of tiny fibers, each of which has its own blood supply. When a muscle is working normally, it tightens, then immediately relaxes or ­releases. Muscle tightness occurs when the muscle doesn’t release as it should. When a muscle becomes chronically tight, the fibers lie closer together. This constricts the flow of blood through the muscle belly, somewhat like stepping on a garden hose reduces the flow of water. The muscle ­operates less effectively when it’s tight, and it may be painful.

All muscles work in pairs of opposites: As one muscle contracts, its opposite ­releases. When a muscle is tight, the ­release process of the muscle is affected. The back muscles extend the horse’s spine, and tight back muscles can’t release to allow for the spinal flexion your horse needs to, for instance, round himself for a bascule over a fence or a nice collected canter. Tightness in the longissimus ­costarum will also affect your horse’s ability to bend around your inside leg.

What Causes It
Back muscle tightness can result from a number of factors. Some of the most common are

• the strain and exertion of repetitive schooling, such as working much more on one canter lead than the other;
• footing that is very deep or too hard;
• an ill-fitting or out-of-balance saddle;
• a very imbalanced rider (whose horse will attempt to compensate for her ­one-sidedness);
• poor saddle placement (for instance, too far up on the withers, which drives the cantle into the back muscles);
• too many pads under a correctly fitted saddle. Contrary to some riders’ belief, this does not reduce pressure on the horse’s back but is more like cramming two pairs of socks inside your shoes.

Tight back muscles can also signal a deeper problem such as hock or ankle issues, weak stifles or ligament problems. How can you know whether you’re dealing with simple muscle tightness or with something more serious? If your horse’s discomfort is not relieved after you have done the massage and exercise sequence I’ll describe on the next two pages a couple of times, you need to involve your veterinarian. (As a general rule of thumb, in my 20 years of practice as a massage therapist, if I find persistent tightness in the forward area of a horse’s back, it may indicate a deeper problem in his front end; if the muscles remain tight in the area near his haunches even after massage, there may be a bigger problem in his hind end.)

Click the link below to access a downloadable, printable PDF.

BCS: What Body Condition Scores Mean, ©EQUUS

Imagine looking down the length of a 100-foot garden hose. Now imagine gathering up that hose and fitting it inside your horse’s belly. One end of the tube is at his mouth, and the other is at his tail, with the majority balled up in his abdominal cavity.

You’ve just pictured a rough image of your horse’s digestive system. One hundred feet of tube through which ­everything you feed him travels, with ­digestion and absorption processes all along the path. That’s a lot of tube. And, when things go right, the system is very efficient. However, so many things happen in those 100 feet, it’s not too surprising that there are quite a few potential problems.

There are also many rules in feeding horses: feed small meals often; feed only high-quality hay; make any feeding changes gradually; never feed cattle feed to horses, etc. Why does feeding your horse seem so complicated, and why so many rules? The answer lies in the architecture of the horse’s gut—how his unique digestive system is designed.

I’ve always thought understanding how your horse’s digestive system works is more important than trying to memorize all those rules. If you understand the architecture of the gut and how digestion and absorption of nutrients works in horses, you don’t need to memorize anything—it all just makes logical sense. Then, when you’re faced with a new situation, you don’t have to try to remember the ­appropriate rule, you can just think of what makes sense. That will help you make the best choices in what and how to feed your horse.

The horse’s gut is fairly unique compared to other livestock species. The horse is classified as a nonruminant herbivore—an animal that eats plants and is not a ruminant. Several livestock species are ruminant herbivores, including cattle, sheep and goats. Ruminants have stomachs that are divided into compartments, whereas horses have simple stomachs with only one compartment. Animals with simple stomachs are classified as monogastrics, including horses, pigs, dogs, cats and humans.

With those basic differences defined, let’s look at the horse’s gut. We’re going to start at the beginning, follow it through to the back end and examine what goes on in each section.

The Upper Gut
The gut starts at the mouth, which the horse uses to take in feedstuffs and chew. In horses, a unique aspect of the mouth is that the physical act of chewing stimulates the production of saliva, which is not necessarily the case in other species. To understand the importance of this, think of saliva as lubrication. If your horse doesn’t chew adequately, there will be larger chunks of feed and less lubrication (saliva) to help the feed flow smoothly through the digestive tract.

Providing regular dental care is the first step horse owners can take to help ­ensure adequate chewing. This decreases the risk of digestive tract problems, such as choke, and helps ensure optimal digestion and absorption of nutrients.

The next part of the gut is the esophagus, or throat. The horse’s esophagus is unique in how it attaches to the stomach. The attachment is at such an angle and the muscles are so firm that once the digesta passes that point, it’s not coming back—it’s a one-way trip. The horse normally cannot belch or regurgitate. In fact, if something makes it into the horse’s stomach that should not be there, such as a toxic substance, his stomach would rupture before he could ever regurgitate.

This is different than in cattle. Cows can belch and “chew their cud” (or ­ruminate) when partially degraded food moves back up the esophagus from the stomach and is then chewed and swallowed again. This allows them to break down less digestible foods so nutrients are more available farther down the tract, which is one of the reasons cattle are better able than horses to utilize poor quality hay.

Now we enter the horse’s stomach. As I mentioned before, the horse has a ­monogastric stomach, meaning a single compartment or a simple stomach. This single compartment contains primarily ­digestive enzymes and hydrochloric acid, so feed is degraded by enzymatic digestion.

This is also quite different from cattle, as a cow’s stomach comprises four compartments, with the largest compartment being the rumen. The rumen is a very large bag—large enough to fill a typical wheelbarrow. It contains billions of microorganisms—bacteria and protozoa. When feed enters the cow’s rumen, it is digested (fermented) by the microbes. This accounts for one of the reasons you should feed your horse only products designed specifically for horses and not cattle, because ­microbes are able to digest and utilize some feed components (and some potentially toxic substances) that digestive enzymes cannot. (For more information, see ”Why Cattle Feeds Don’t Work,” below.)

Another function of microbial fermentation is the digestion of fiber carbohydrates in the diet. Fibers are made of sugars linked together by a bond that requires a microbial enzyme to break. In ruminants, microbes in the rumen break down fibers into volatile fatty acids (VFAs). The VFAs are then absorbed from the small intestine and are an important energy source for the animal.
In the horse, these fibers pass through the stomach and small intestine with very little breakdown. This is another reason to feed high-quality hay to your horse. The more fibrous the hay, the less digested it will be in the upper gut (stomach and small intestine) and the fewer nutrients your horse will get out of the hay. Cattle are quite efficient at ­retrieving nutrients even from fairly poor-quality roughages due to the microbial fermentation in the rumen.

One more interesting difference between the equine and bovine stomach is the rate of passage. In cattle, it can easily take 24 to 36 hours for feedstuffs to pass through the entire stomach. In horses, digesta usually passes through the stomach within two hours, though it can be as short as 15–20 minutes. The faster digesta moves, the less efficient digestion processes may be.

Moving on, the next part of the horse’s gut is the small intestine. This is a tube that is about 3 inches in diameter and 60–70 feet long.

As digesta moves through the small intestine, more digestive enzymes are produced, and nutrients are degraded into components that can be absorbed into the bloodstream. In fact, the small intestine is the major site of nutrient absorption: Most if not all of the fat in the diet is digested and absorbed here, soluble carbohydrates (sugars and starch) are primarily digested and absorbed in the small intestine, and it is the only appreciable area of absorption of amino acids from dietary protein. The ­majority of vitamins and several minerals are also absorbed in the small intestine.
Here again, the rate of passage of digesta through the small intestine is fast—as short as 45 minutes, with a maximum rate of about eight hours. In 10 hours, feed has passed all the way through the stomach and small intestine in the horse.

Anything that we can do as horse owners to slow down the rate of passage in the stomach and small intestine can help increase the efficiency of digestion and nutrient absorption. About the only way to do that is to slow down your horse’s rate of intake. Feeding management practices such as placing large, round stones in the feed tub can accomplish that goal—your horse has to pick around the stones, slowing down intake.

Mackler and his wife Judy bought the sorrel Quarter Horse gelding in 2002, when he was 7 years old. Five years later, in late winter, they began to notice he was having problems urinating. “He began straining and grunting every time,” says Mackler. “And he’s not a complainer.”

Tucker was urinating frequently in short streams that over the course of about three weeks eventually petered out into slight

Some bladder stones can be broken up into small pieces that are passed out with the urine. Because Tucker’s stone was so large and solid, however, it had to be removed surgically. ©Tom Moates

trickles and then dribbles. Worried, the Macklers called their regular veterinarian, Dennis Farrell, DVM, of Ridge, New York, to come and check Tucker out.

Tucker’s signs were consistent with a urinary infection, a painful inflammation in the urethra0 and/or bladder caused when bacteria or fungi from the surface of the skin invade the urinary tract. Horses with this condition often strain to urinate, with frequent attempts that produce only small amounts of fluid or none at all. “[When investigating a problem] you start with what happens 95 percent of the time,” says Farrell. “So we looked for infection, took a blood sample, cleaned his sheath and put him on some antibiotics.”

Within days, the dribbling cleared up and Tucker seemed more comfortable, but over the course of a week or so all the signs of trouble returned. Farrell prescribed another course of antibiotics and again the signs cleared up, only to return. This cycle went on for nearly six weeks into early March.

The Macklers and Farrell explored other possible causes for Tucker’s issue, but they kept coming up short: The other horses living with Tucker were on the same feed and running in the same paddocks, and none showed problems of any kind, so some type of environmental toxin was unlikely. Urinary infections in horses often occur in conjunction with other illnesses or skin infections, but Tucker had never spiked a fever and he was otherwise healthy. Other than the strange urination, there didn’t seem to be anything wrong with the gelding.

All blocked up
The break in the case came when Tucker began showing mild signs of colic one afternoon. As Farrell did a rectal exam to check for impactions, he noticed that Tucker’s bladder was very full and extended. Normally, a horse would be anxious to empty it, but Tucker showed no signs of trying. Farrell passed a catheter up the gelding’s urethra and into the bladder to evacuate the urine. Once his bladder was empty, the signs of Tucker’s colic vanished. “He went from miserable to chipper in a matter of minutes,” says Jim Mackler.

This was an important clue, which told Farrell that the gelding had an issue with his bladder---something was preventing him from emptying it. Farrell performed another rectal exam to feel the empty bladder. “That’s when I felt a mass,” he says. Through the muscular walls of the organ, he could feel a round, hard object. It was, in all likelihood, a bladder stone.

Bladder stones are rare in horses.“I’ve seen this twice in 25 years,” Farrell says. The causes of this are not known, but most develop in a predictable way: Under certain conditions, dead cells, proteins and minerals that are normally washed out with a horse’s urine collect to form tiny crystals. Additional cells and debris then become attached to one or more of these crystals, called niduses, to form larger rocklike masses. If these get big enough, they remain trapped in the bladder, where they can block the  entry to the urethra and prevent the outflow of urine. Most of these stones are composed primarily of calcium carbonate, but other minerals, such as magnesium and phosphorus, may be included as well.

Male horses are much more likely to develop bladder stones than mares are because of differences in their anatomy. The female horse’s urethra is shorter, wider and distends more easily than a male’s, and so small and moderately sized particles can pass out more readily, and larger masses are less likely to develop.

All of Tucker’s signs were consistent with bladder stones: first the dribbling and straining, and then the colic once the stone had grown large enough to prevent him from urinating at all.

Make way
Tucker’s situation was an emergency. If his bladder filled again while he remained unable to urinate on his own, the organ could rupture. Farrell immediately referred the gelding to the Mid-Atlantic Equine Medical Center in Ringoes, New Jersey, and the Macklers loaded him up for the 100-mile trip.

Patty Doyle-Jones, DVM, DACVS, met Tucker when he arrived. “I knew he had been exhibiting a history of painful urination and dribbling, and that Dr. Farrell had felt what he thought was a stone,” she says, “but [otherwise] Tucker was a healthy horse when he got here.”

Doyle-Jones started by performing a rectal exam to feel the mass herself before continuing on to more thorough diagnostic techniques. “We did ultrasound imaging of his kidneys,” she says. “The left one was normal, and he had some slight calcium grit in his renal pelvis on the right side---not like very large stones or anything, but there was some grit there. And then we ran the endoscope up from the penis into the bladder, and you could see the bladder stone sitting right there. We estimated the stone to be eight centimeters across.”

Several techniques exist for removing bladder stones. They can be surgically removed, or sometimes they can be shattered within the bladder into pieces small enough to flush out with the urine. This second approach, called lithotripsy, can be accomplished with lasers, with shock waves or manually, with a long metal tool called a lithotrite that is inserted in the urethra. Lithotripsy is less invasive than surgery, but it does carry the risk of burning, abrasion or other injury to the bladder wall, and sometimes the initial procedure may not break the stone into small enough pieces. Which approach is best for each case depends on several factors, including the gender of the horse and the size of the stone.

Gender matters, again, because of the differences in the size and shape of the male and female urethra. “The position of the urethra on the floor of a mare’s bladder makes it easier for small particles to be voided with urine,” says Doyle-Jones. “If they do develop stones, they are easy to reach and break up so they can be passed. Some smaller handed vets can actually reach through the urethra into the bladder and remove them directly.”

But a gelding’s longer urethra not only makes the stone harder to reach, the position of its opening in the bladder also makes it difficult to flush the debris if it is crushed. A veterinarian might have to repeatedly flush the bladder, then use an endoscope to ensure all of the pieces had been cleared.

Nevertheless, Doyle-Jones says that the majority of bladder stones she sees do not require major surgery: “Most of them you can treat standing because they are small enough when they’re diagnosed you can just go in and pull them out. The larger ones are not all that common.”

But Tucker’s stone was very large and solid. “We decided the better option was to put him under general anesthesia and remove the entire stone at once,” says Doyle-Jones. (She adds that lithotrite designs have improved since 2007, when Tucker was treated, and they are now more effective than they were then. If she faced the same case today, Doyle-Jones says, she might try to break the stone manually.)

Relief at last
Tucker was positioned on his back for the procedure, and Doyle-Jones made an incision near his sheath to access his abdominal cavity. For a horse in this position, the bladder has to be lifted up from the floor of the pelvis to the opening in the abdomen. “You have to work it carefully to allow the smooth muscle to relax in order to lift it and position it for the incision,” says Doyle-Jones.

Once the bladder was in place, surgical drapes were placed around it to prevent any urine from leaking back into Tucker’s body. Doyle-Jones made a small incision in the organ, reached in and removed the stone. Then she sutured the bladder closed, repositioned it back in the body and closed the primary incision.

Tucker recovered at the clinic for the next week. He received antibiotics, anti-inflammatory drugs and painkillers. He was also monitored to make sure he was urinating normally. “Usually horses have no problem with bladder function after this,” says Doyle-Jones. “We didn’t put a catheter in Tucker and we typically don’t have to. The bigger concern is infection at the primary incision, and he didn’t show any signs of that.”

Tucker’s convalescence continued after he returned home. “He was on stall rest for about a month to make sure he didn’t damage his incision,” says Judy Mackler. “But when he went back out with his friends he had no problems at all. We started riding him shortly after that.”

The Macklers also continued to monitor his urination habits. Horses who have had bladder stones are at a slightly higher risk of recurrence in the immediate period after removal, especially if the stone was broken and some particles were left behind. But, says Doyle-Jones, after they have been free of stones for several months, they are no more at risk than any other horse.

Since his procedure, the Macklers have never seen Tucker groan, strain or dribble while urinating, but Judy comments that he does seem to go more often then he did before.

“It’s possible they are just more aware of when he goes,” says Doyle-Jones. “Or it’s possible there is a very small adhesion or scar that’s limiting how far his bladder can expand. As long as he appears to be voiding normally when he does go, there’s no need to worry.”

The only permanent change the Macklers have made in Tucker’s care is to remove alfalfa hay from his ration. Although it’s not known why horses develop bladder stones, one theory is that high levels of calcium in a horse’s diet may contribute to the problem, and alfalfa contains significantly more of that mineral than grass hays. This possibility cannot be the entire answer, because many horses regularly eat alfalfa and never develop the stones. But just as a precautionary measure, Doyle-Jones suggested switching Tucker off of alfalfa altogether, a policy that the Macklers have strictly adhered to ever since.

In theory, changing the diet to increase the acidity of a horse’s urine could also prevent the recurrence of bladder stones, since calcium carbonate needs an alkaline environment to form crystals. But, says Doyle-Jones, “We’ve never really found a way to keep the urine acidified enough to keep that calcium carbonate from forming those stones. We never do really figure out why they have it.”

In the five years since Tucker’s bladder stone episode, he has continued to be healthy and active with no further signs of trouble. And he is still a charming all-around horse anyone can ride. “He’s really one in a million,” says Jim Mackler.

Last fall I wrote on “Vegas,” Turtle Powell’s standout head horse, and his medical problems, including laminitis. This column is an update on Vegas, courtesy of Turtle and Vegas’ farrier, Blaine Chapman, with some general comments along the way on laminitis in horses, aka “founder.”

Vegas’ problems started last summer with a respiratory infection that had as a consequence a vascular disease (purpura hemorrhagica) and ultimately resulted in significant laminitis. General comment number one: Laminitis can result from a variety of causes. Laminitis literally means inflammation of the lamina. The lamina are the interlocking structures that form the weight-bearing bridge between the inside of the hoof capsule and the corium (covering) of the coffin bone. These cause symptoms of laminitis, which I'll discuss below.

When these structures become inflamed they swell, exude serum and functionally the connecting bond gives way to the stress of weight-bearing and they fail. Efforts to minimize the damage become the objective in dealing with this condition. These efforts include systemic medications, local treatment (such as soaking the feet) and supportive measures to try and stabilize the anatomical structures of the foot. General comment number two: It takes a dedicated team of owner and specialists in the field to have a chance for success in significantly impacted horses with this condition.

Turtle related that the most discouraging days were right before he left to go to the NFR (Wrangler National Finals Rodeo) last December. Vegas had basically been lying down for two weeks. He was eating and drinking well, but would not get up. Turtle called in Blaine Chapman, a horseshoer he knew who has had a lot of experience in dealing with this condition. Blaine encouraged Turtle to wait out the bad spell because, considering the severity of Vegas’ founder, his state was to be expected.

In this horse’s specific condition, it was decided to resect (remove) the anterior hoof wall, which was known per radiographs to have already separated from the coffin bone, plus using special supportive shoeing as the basics of treatment. General comment number three: This example pertains to the circumstances of this specific case. There is no “one size fits all” or singular approach to treating this condition.

This photo shows the anterior hoof wall having been resected. The bottom of the shoe is specially designed to support the coffin bone during the healing process. (It takes six months to a year for the hoof wall to grow from the hairline to the ground.)

Photo courtesy Turtle Powell

Laminitis has received a good deal of attention and study in the last few decades. To this point, there has not evolved any “silver bullet” treatment regimen for the problem. It should be treated as an emergency, but unfortunately, by the time one notices symptoms of painful feet there is already the start of degenerative changes in the critical areas of the foot. We continue to wish Vegas the best possible progress, and will keep tracking his condition as he is no doubt one of the great ones.

The more researchers learn about laminitis, the clearer it becomes that it’s not a disease just of the hooves. The events that culminate in the inflammation of the soft tissue of the feet usually begin in the digestive tract or even the endocrine system. Horses who are prone to laminitis also typically have characteristic traits evident far from the feet, such as fat pads over the withers or large, cresty necks. Indeed, to understand the causes and earliest physiologic processes of laminitis, you need to look at the entire horse, not just his hooves.

Nonetheless, when a horse is diagnosed with laminitis, it’s his feet that require the most attention. That’s because by the time a horse begins showing clinical signs of laminitis, the tissues of his hooves may be so damaged that they give way, releasing the coffin bone from its moorings to rotate out of position or “sink” downward to and even through the sole of the hoof. This change in the hoof anatomy, commonly known as founder, can be devastating.

Intensive hoof care, however, can help mitigate the pain associated with these changes as well as halt the damage. No trim or shoe can restore the hoof to its original condition, but a treatment approach devised by a veterinarian and farrier can be the difference between a sound, useful life and eventual euthanasia for a horse. A successful treatment plan will likely combine specialized trims and therapeutic shoes and will need to continue for months as the hooves recover. In some cases, a horse may require lifelong therapy to remain comfortable and sound. Knowing what’s involved with post-founder hoof care can help you be prepared to do all you can to help your horse.

Damage assessment
In the immediate aftermath of a laminitic episode, a farrier or veterinarian will formulate a treatment plan based on how much damage has been done to the hooves. Hoof testers and an experienced eye are helpful, but they are no substitute for radiographs. “I take x-rays to see how much rotation there is,” says Tia Nelson, DVM, a veterinarian/farrier in Helena, Montana. “These can be useful to have as a baseline, a starting point. If we need to, we can refer back to those first x-rays to see if we are making progress or are still at ground zero.”

In the best-case scenario, an x-ray reveals no movement of the coffin bone, which means the laminitis did not progress to founder. Once the acute inflammation dissipates, a full recovery is possible without any specialized hoof care. Unfortunately, many laminitis cases don’t unfold that way, and the radiographs become a tool for determining the extent of the resulting founder.

Radiographs also provide a basic blueprint for shoeing, says Scott Morrison, DVM, a veterinary podiatrist at Rood and Riddle Equine Hospital in Lexington, Kentucky: “Knowing exactly where the bone is will tell you where the breakover needs to be, how much heel to take off, how much wedge you need. Without radiographs you are guessing. Unfortunately, there are circumstances where radiographs won’t be possible. Then you are working under compromised conditions. A farrier who has worked on hundreds of chronic founder cases can probably look at a foot and draw a picture of where that coffin bone is in the foot and be pretty close, but even then a person can be fooled occasionally. I still shoot radiographs because it’s good insurance---to know exactly how the coffin bone is sitting---and it may also show any other pathology that might be there.”

There is no standardized scale for grading founder so the terms individual veterinarians, farriers and horsemen will use can vary. (You may hear the word “chronic” used along with “founder,” but that’s a redundancy. Chronic, in medical parlance, means long-term and not likely to be resolved. Laminae do not regrow. Damaged tissues may heal to strengthen the attachment of the bone to the hoof wall, but dead laminae are gone forever and a bone moved out of place permanently alters the internal conformation of the hoof. All founder then, by definition, is chronic.)

Morrison puts founder into three categories: “low grade,” “stable” and “unstable.” The category a horse falls into will depend upon the changes seen in the hoof and provide guidance on how to best manage them.

Low-grade founder: It’s all about sole
This insidious type of founder develops slowly over the course of months or even years, usually as a result of metabolic imbalance or neglected hooves. “A low-grade case of founder is sometimes misdiagnosed as just a bad-footed horse,” says Morrison. These horses may have never had an acute episode of laminitis to draw the attention of caretakers. They may never even seem lame.  Instead, they may simply seem “ouchy” for a few days in the spring or appear to have a preference for softer footing. Often the problem isn’t even suspected until radiographs are taken.

The exterior of the hoof with low-grade founder is likely to appear normal, but a close look at the bottom of the foot and radiography reveal minor but important changes. “Usually the white line is stretched at the toe, making the horse more prone to white line disease,” says Morrison. “When you radiograph these feet there may be a degree or two of coffin bone rotation.”

Fortunately, he says, hooves with chronic low-grade founder are fairly easy to manage by just improving the condition of the sole, which in turn supports the coffin bone: “If the horse has thin soles that are easily bruised you may just need to thicken up the sole depth. Sometimes just shoeing with a regular keg shoe, a wedge and a rolled toe is all that’s required to help the sole become stronger and thicker.” Morrison usually uses glue rather than nails to apply the shoes for the first two or three shoeings. Once the sole is thickened, he lets the horse go barefoot and rolls the edge of the hoof walls.

“Where the sole meets the wall it is fairly tough and strong, compared to the inner central part of the sole. The perimeter becomes calloused and strong,” Morrison explains. “With this process of letting the sole thicken by first protecting it with shoeing, the feet grow out beautifully. The cracks in the wall grow out and the foot becomes shiny and healthy rather than dull and shelly; the integrity of the wall changes.”

Julie Bullock, DVM, of Mount Sidney, Virginia, adds that frequent trimming is paramount in these cases, because it keeps the toe short to ease breakover. “Some of these horses grow very little sole, so they are often sore. Sometimes I put them in boots that can be taken on and off with Velcro. Those boots can be used intermittently, depending on the footing,” she says. “Ideally, you want to get the horse to where he can go barefoot. That’s easier on the horse and the pocketbook---just doing frequent trimming to keep the feet short and at the proper angle.”

Travis Burns, a lecturer and farrier at the Virginia–Maryland Regional College of Veterinary Medicine, says it can be helpful to use sole and frog supports in low-grade cases of founder until the sole naturally thickens. “Chronic laminitic horses that have adequate sole depth do very well, but if they lose their sole depth they become uncomfortable and tender very quickly,” he says. “You can create artificial sole depth, using things like packing or silicone pads. If you are lucky, the horse can grow more sole himself, after a while.”

Stable founder: Out of rotation
Cases of what Morrison describes as “stable founder” typically have mild rotation or movement of the coffin bone due to persistent low-level inflammation of the tissues. Like low-grade founder, the condition doesn’t arise from a single carbohydrate overload after a raid on the feed room, but instead from an underlying physiological problem that continually stresses the structures of the hoof. Nor are these horses likely to have an episode of acute pain, but they are more likely than horses with low-grade founder to be continually tenderfooted and “off.” Stable founder is also more likely to produce exterior evidence of the damage being done inside the hooves.

“There is more hoof capsule distortion than in low-grade cases. The heels grow faster than the toe, and there are founder rings around the hoof. There’s more dishing at the front of the foot, and stretching of the white line,” says Morrison. “This is the typical foot you’ll see in a horse with metabolic syndrome.”

Radiographs will reveal rotation of the coffin bone, caused by the pull of the deep flexor tendon. The rotation isn’t typically progressing, hence the term “stable,” but is still the primary consideration in mapping out a shoeing protocol. “One of our major shoeing goals is to decrease the pull of the deep digital flexor tendon and rehabilitate those feet,” says Morrison. “Therefore, the shoe requires some degree of wedge at the rear and also a rolled toe, to take some of the stress off the laminae during breakover.”

Even when an underlying metabolic problem is controlled through management changes, stable founder will persist and require continual care. “Usually those feet can’t get to where they can go barefoot,” says Morrison. “The majority of them need to stay in some type of shoe because the laminae are more compromised. The foot needs more protection and you need to keep the coffin bone at a better angle.”

A common and time-honored shoeing technique in these cases is a standard shoe tacked on backward, says Paul Goodness, a farrier with Forging Ahead in Round Hill, Virginia: “Some people may use a reversed shoe to provide support across the heels without putting pressure on the toes. The toe area is usually painful for about three months and incapable of being a weight-bearing structure. So we concentrate support on the back part of the foot---the frog and the heels---any area that is not painful. This gives the damaged laminae in that area some relief.”

Other styles of shoe perform the same function. “We do this with many different types of shoes, such as an egg bar, heart bar or anything that provides support across the back of the foot,” says Goodness. The exact shoe will depend on the specific situation, but some aspects of the technique are universal: “The ground surface of the shoe must be beveled appropriately, for easy breakover, to relieve some of the stress on the front of the foot when moving forward, or help prevent shearing of the laminae when the horse turns,” he says.

Whether it’s better to use nails or glue to attach the shoes depends on the quality of the horse’s wall, says Morrison: “If the foot is very sore, the horse may not tolerate nailing. Low-grade foundered feet tend to have very thin walls. I often glue the shoes on those. By contrast, many of the stable founder cases are Cushing’s horses or have metabolic issues, and some of these individuals have good, strong walls, especially ponies, Andalusians, Arabians and Morgans. These hardy horses usually have strong, good-quality feet and hoof walls, and you can nail the shoes on when correcting the rotation. But if an individual is painful you should glue the shoe instead---at least for a couple of shoeings until the feet are more comfortable.”

Whatever the approach, horses with stable founder need frequent farriery work to make sure the hoof doesn’t grow too long, which would put more leverage stress on the foot. “Those horses tend to get more out of balance than a normal foot would between each trimming/shoeing,” says Morrison.

You’ll know when the shoeing is correct by looking at the growth rings on the foot. Foundered feet typically have wide growth rings at the heel and narrow rings at the front because that hoof horn grows more slowly there. “When you get the shoeing mechanics and hoof angle just right, you start to see the hoof wall growing out more evenly, heel to toe,” explains Morrison.

Unstable founder: All hands on deck
In unstable founder, the foot has sustained significant structural damage that will worsen without intensive intervention. These cases typically occur in the aftermath of an acute laminitic episode, such as one brought on by an overload of grain or systemic illness, but they are also seen in horses whose minor founder went untreated and was exacerbated by poor hoof care or metabolic imbalances. In any case, growth centers of the foot are so severely compromised that growth of the sole, wall or both stops.

A horse with unstable founder is likely to be very lame, and radiographs will reveal dramatic rotation of the coffin bone, which may even also drop down to or through the sole (“sinking”). And, because the hoof is so compromised, the damage escalates quickly. “These horses are best treated by a veterinarian and farrier who specialize in these cases, or by an equine podiatrist---a veterinarian who specializes in foot problems,” says Morrison. “With such help, the unstable cases often can be stabilized and rehabilitated back to pasture soundness or even low-intensity riding.”

Standard treatments of unstable founder incorporate the techniques used in the low-grade and stable cases---including increasing sole depth and supporting the hoof heels while taking pressure off the toe---but with fewer guarantees. “There is a limit to what can be done with shoeing, if the pull of the tendon is overpowering, so we have to try something else,” says Goodness.

In unstable cases, it’s critical that farriers and veterinarians work together closely, combining skills and techniques to help the horse. For instance, says Goodness: “The veterinarian will often use something like Botox to lessen the pull of the tendon by temporarily paralyzing the muscle/tendon. The Botox is generally injected into one of the deep flexor muscle bellies and it temporarily weakens them, which reduces the pull from that tendon. Effects of the Botox seem to wear off in about six months. This may give the farrier a window of opportunity to correct the rotation and realign the coffin bone so the horse can regrow a new hoof capsule down around it.”

A more drastic approach is to cut the deep flexor tendon. “This also gives the farrier quite a bit of time to get things straightened out,” says Goodness. “Eventually the tendon heals and reattaches and often, the horse progresses and his feet and tendon heal so he can be turned out or sometimes even used for light riding. A certain percentage, however, develop some scar tissue and adhesions around the surgical site. If that happens, the horse may have limited athletic ability because the tendon doesn’t work quite as well anymore.”

Research into rehabilitating the hooves of horses with unstable founder continues: “One of the newer things some people have been trying on severe cases is injecting the foot with stem cells,” says Goodness. “The jury is still out on that, but the early information indicates that this may be a useful treatment, especially for sinkers. We are still learning about this treatment possibility, but in the future this may become a good weapon to add to the arsenal for treating chronic founder.”

No matter where it starts within a horse, laminitis that progresses to founder takes the harshest toll on his feet. That’s why hoof care is such an important cornerstone of treating, rehabilitating and maintaining horses who have foundered, and why it continues to be an area of intensive research for both farriers and veterinarians. Until a way to prevent laminitis entirely is found, the best defense against long-term debilitation will remain focused on the feet.

March 27, 2012—Nature, not the farrier, shapes the feet of feral horses. A school of “natural” hoofcare holds these feet up as a model of health, and followers try to replicate the shape in domestic horses. But the model may not be all it’s cracked up to be, says a report from Australia.

The report summarizes 14 studies backed by Australia’s Rural Industries Research and Development Corporation, a government agency. Researchers looked at genetics, travel profiles, nutrition, foot shape and structure, and foot health in a large number of feral horses from different environments. Here are three key findings:

There’s more than one model. Researchers who looked at feral horses from six environments identified six different foot models—because environment changes foot shape. The distance feral horses travel to find food and water and the type of surface they travel on determine hoof structure. The short-walled hoof usually considered the natural model is a desert foot, shaped by long-distance travel over hard, dry ground. On softer footing, with food and water close at hand, hoof growth exceeds wear and feet grow long and flared.

Change may be good or bad. The fact that the horse’s feet respond to the environment doesn’t mean that they always adapt in ways that help the horse. Long, flared feet are prone to cracking and injury, and some desert feet show excessive wear.

Natural doesn’t mean healthy. The researchers discovered high rates of foot problems in the feral horses. A study that examined the left forefeet of 100 horses found 377 significant abnormalities; only three feet had no problems. A combination of high travel and hard ground was linked to more serious foot problems.

Although feral horse feet often appear healthy and at first glance seem an ideal model for domestic horses, the researchers say that the model should be reconsidered. “Best practice in hoof care should evolve from passed-on knowledge, new research, clinical practice and practice review. Knowledge of wild horse and feral horse feet provides useful supportive information, but a feral horse foot model should not form the basis for the foot care of the domestic horse,” the report concludes. You can download the full report online at www.rirdc.gov.au.

This article originally appeared in the April 2012 issue of Practical Horseman magazine.

Question: I am doing a science fair project on the effects of conformation on the jumping horse. What points should I follow that would have the most significant effect on the way a horse jumps?

John: Unfortunately, I can’t answer this because it is based on looking at the entire horse—his balance and proportions—not just at specific parts.

Question: When evaluating a horse, which conformation faults are you most likely to dismiss in terms of suitability for athletic performance? Which faults do you consider most serious?

John: Most serious: uneven feet, low heels; curled-under heels; any indication of soft-tissue damage, like bowed tendons. Less serious: splints, cow hocked and toed out.

Question: It seems like conformational leg issues that you pointed out in your presentation did not, in general, cause lameness problems. Which leg conformation issues would you avoid?

John: Tied-in at the knee and over at the knee.

Question: Are there any conformational flaws you would absolutely stay away from?

John: Horrible feet, and I tend to stay away from horses who are over at the knee because it puts far too much stress on the tendons.

Question: Are "no heels" on a horse correctable?

John: They may be correctable, but it is very difficult and not always correctable. It takes a very good blacksmith and a lot of time. It is one of the defects that I really avoid. It is probably the most serious flaw in my mind.

Question: Is toeing in below the ankle an issue?

John: An issue? Yes. Deal breaker? Not necessarily. Though I have had better luck with horses who toe out than with horses who toe in. Every fault is an issue.

Question: What’s your opinion of a slight clubfoot defect?

John: Slight clubfeet don’t bother me too much. They can be managed with a good blacksmith.

Question: How do you see a good foot through bad farrier work?

John: Mostly, a good foot can survive a lot of bad farrier work. Though farriers get blamed for bad work when, many times, the horse just has bad feet. The best way to tell good feet in general is to try to look at it in the whole leg and how the lines all fit together and how the foot is attached to the leg.

Question: Big Ben had a lot of shoulder but it was pretty straight in angle. Same with Abdullah. What shoulder angle do you have the most success with?

John: I don’t look at shoulder angle by itself; you must step back and look at the bigger picture to see how the shoulder angle relates to the other angles and to the hind end to evaluate potential ability.

Question: How does the conformation of the horse's back affect jumping ability?

John: It has to do with balance and coordination. It’s too complicated to dissect to this level, which is why I like to look at it from a whole horse perspective and evaluate balance and proportions.

Question: What are the most common injuries in jumpers that you see as related to conformation?

John: Sore backs are an occupational hazard. Horses who have the structure and the power to do the job may have an increased tendency to hurt their backs.

Question: I've heard longer-backed horses are usually scopier. What is your experience with that?

John: I would agree, but any extremes can be detrimental. Long-backed horses can be hard to shorten and can be prone to back injuries.

Question: On a head with a lovely eye and nice well-set ears, what is your feeling about a slightly convex profile?

John: It wouldn’t be a deal breaker, but it is not my personal preference. I prefer slightly convex to slightly concave if I had to choose, but be careful that the horse is not obstinate.

Question: Are there any positives to a horse with a longer back line from the point of hip to the hock? She has a long tibia/fibula.

John: The ratio of that line to the cannon bone is important but it comes down to proportion. Too long can be a detriment because it becomes a mechanical disadvantage if the lever becomes too long and too much muscle is needed to move the bone.

Question: How much weight do you give to a horse's breeding? For example, Darko produced some wonderful offspring; would you ignore more conformation faults in a Darko baby just because of its breeding?

John: If the horse is a stallion or mare, it matters a little bit. However, I use breeding only to confirm thoughts or feelings that I already have to reconfirm the characteristics of the bloodline for conformation, soundness, scope, carefulness and temperament.

Question: What is given more weight in evaluating a jumper—breeding or type? Would you take on an unusual breed (e.g., Morgan/Thoroughbred ) if it was put together well?

John: Type is more important. If the horse in question was put together well, I would take it on, but the odds are against it. The characteristics of other breeds would probably preclude it. I have found that Thoroughbreds and warmbloods are the best suited for jumpers.

Question: Many winners of breeding classes don’t go on to win jumper or hunter classes. Why is that?

John: I think it is because the criteria are wrong as the pretty horse beat the well-put-together horses.

Question: Do you have a preference among stallions, geldings and mares?

John: No, no preference. But generally geldings are more tractable. Stallions can be more obstinate, and mares can be more temperamental. But all of those things can be seen as advantages or disadvantages.

Question: What are your thoughts on young horses who are very brave and truck around the ring like seasoned campaigners but who are not careful and get the occasional lazy rails?

John: There is no chance to improve on that. They can be nice horses for some jobs, but it will just get worse over time, in my opinion.

Question: Could you say something about horse size? All things being equal in terms of conformation and temperament, do you prefer one height over another?

John: 16.1–16.3 hands is ideal. Conformationally it makes the most sense because that is the size where you get enough leverage from length of the skeleton without overloading the skeleton with muscle to move the bone. It’s the most versatile package, in my opinion.

Question: How do you apply your principles when looking at, say, weanlings or really young horses who will change shape a lot?

John: Let them grow up a bit before evaluating them. For sure you can see major flaws at a young age, but for jumpers there are too many different types that are good that you should not preclude any young horse from being a good horse, barring a huge defect.

Watch a replay of the webinar “Evaluating Horse Conformation for Potential” with John Madden.

The horse conformation webinar focused on assessing horses by body type to determine which animals are built to succeed as sporthorses. John Madden also examined performance-limiting conformation traits and reviewed horses that are exceptions to the rules. Watch the recording of the webinar below!

John Madden has extensive experience with sporthorses competing at the top level. He has trained riders at four Olympic games, multiple World Cup finals and World Equestrian Games. John is based at John Madden Sales, Inc. in Cazenovia, New York, with his wife, Olympian Beezie Madden.

Webinar attendees submitted more questions than could be answered during the time allotted. Read John's answers to those questions at "21 Sport Horse Conformation Questions with John Madden."

After I lost a wonderful trail horse to a tragic accident, I was depressed and did not even want to start looking for another one. But my loyal friends, knowing how much I need a horse in my life, dragged me all over Michigan. Yet my response to every horse for sale was always, “No, thank you. Not quite right.” This went on for the entire summer of 2009.

Finally, while we were riding one day in our favorite local park, my friend and I met a couple with some very nice Quarter Horses. Casually I asked, “Do you know of anyone who might have a nice trail horse like yours for sale?” The man said he had a few, and he lived only 45 minutes away. On a very cold, windy November day, my friend and I made the trip.

I said that I really wanted a quiet horse so my granddaughter could ride too, and the man brought in from the pasture a 5-year-old Quarter Horse mare named Jodie. Her owner mentioned that she had not been ridden for a few months, so I was a bit wary. But he saddled her up, led her out into his 50-acre hay field and just hopped on. She walked right off and then he loped her around the field. Just then, a little old pony who roamed freely on the farm came cantering in and ran in circles around the mare. Jodie was unfazed and just kept loping along as nice as could be.

My friend and I took turns riding the mare, who seemed unconcerned about everything---just what I had been looking for. I purchased her the next day.

A sudden change
Jodie settled into her new home quickly. She was turned out 24-7 in a pasture with a run-in shed, keeping company with two ponies that belonged to my granddaughters. She also made an easy transition to our meal plan---grass hay to supplement the fall pasture, plus a token amount of complete feed.

The weather was beautiful, so I started riding Jodie right away at the state park. From our first outing, she was perfect. She walked out happily and freely and cantered beautifully down the trails. I rode as much as
possible that fall and through the winter and spring.

But the next summer, Jodie’s personality began to change. When I tightened the cinch, she’d pin her ears and try to bite me. I suspected the problem was back pain---she has a broad back and I’d been having a terrible time finding a saddle that fit her well. It seemed I was shipping saddles back and forth from tack shops almost every other week.

Despite my efforts to find a better saddle, Jodie got more and more miserable. In late October, she began stopping at the bottom of hills and would go up only with urging. Then one day she did not want to continue her canter. When I asked her to move on, she actually bucked and pinned her ears---this
from a horse who could have won the Miss Congeniality award just a few months earlier.

I knew this had to be more than just an attitude problem, so I called my veterinarian, Robert Renton, DVM, of Howell Animal Hospital. As he examined Jodie, it took him only a few minutes to discover the
nature of the problem: When he pushed gently on her side, she pinned her ears and tried to kick him. He carefully continued the exam and listened closely as I described the changes in the mare’s behavior.

Jodie was clearly in pain, Renton told me when he’d finished. That conclusion was easy. The difficult part would be figuring out what was causing it. My mind reeled as the veterinarian outlined what seemed like an endless list of potential causes, ranging from poor saddle fit to hock pain, ulcers and ovarian tumors.

A few of the possibilities didn’t seem likely. Gastric ulcers, for example, can cause overall grumpiness, but Jodie’s outdoor, hay-fed, low-stress lifestyle didn’t fit the profile for that condition very well. Renton also discussed a type of muscle disorder, but most horses affected with that have asymmetrical hindquarters and are on high-grain diets, neither of which was true for Jodie.

Renton suggested that I continue looking for a better-fitting saddle while we worked down the list of more probable causes of Jodie’s pain, beginning with the most likely one---her hocks. Renton took a series of radiographs of both Jodie’s hocks. Everything looked healthy and normal, but just to be sure, we started her on a course of phenylbutazone, which would reduce any pain and inflammation, to see if she would improve over the next few weeks. She didn’t.

To investigate the next possibility, Renton returned to do a full reproductive exam, including an ultrasound of Jodie’s ovaries and blood work to look for abnormal hormone levels. A growth on her ovary would be painful, and it would also secrete hormones that could explain her aggression. Once again, though, everything was normal.

And Jodie’s pain continued unabated. Things seemed to be at their worst around Christmas of that year. We had unusually nice weather just before the holiday and I slipped onto Jodie bareback to take a walk around the pasture. But the moment I sat on her, she pinned her ears, braced her back and sent me a very clear message that she hurt. I knew then it wasn’t the saddle, and I was starting to worry that my sweet mare was forever changed.

I wasn’t ready to give up, however. The next rule-out Renton suggested was equine protozoal myeloencephalitis (EPM), a progressive neurological disease caused by a parasitic infection of the central nervous system. Jodie didn’t seem particularly uncoordinated, as horses with EPM typically are, but she had started to drag her hind toes as she walked, which can be an early sign of the disease. A blood test for antibodies to the protozoa came back positive, which meant she had been exposed to the organism, as about half of U.S. horses are, but that doesn’t necessarily mean that they have the disease. Only about 1 percent of the horses who encounter the protozoa, which are consumed with contaminated feed or water, ever develop signs of illness.

To explore this possibility, we could have had a spinal tap performed. This procedure involves drawing a sample of cerebrospinal fluid from the spinal canal to look for the presence of the protozoa, but the test is invasive and can still yield false positives. What’s more, it would require taking her to a university hospital. Or, Renton suggested, we could just start Jodie on the medications for EPM and look for improvement. I opted to skip the spinal tap and begin the treatment. I had high hopes it would help. But it didn’t.

Gastric ulcers were next on our list. These painful lesions in the lining of the stomach can cause a number of subtle signs, including vague pain and touchiness, especially when being saddled. They are more likely to occur in horses kept in stalls, fed a high-grain diet and subjected to a stressful lifestyle, including travel and competition. But although Jodie lived outdoors and ate mostly hay, she did show some signs of digestive discomfort. Every morning when I went out to feed, she had moist ruffled hair on both her sides where she had bitten at herself.

Gastric ulcers can be diagnosed with an endoscope, a long tube with a camera inserted down the esophagus and into the stomach, but many veterinarians will simply administer the medication to treat ulcers, GastroGard, and watch to see if the signs of discomfort dissipate. We put Jodie on GastroGard, and after a month she did stop biting her sides, but she remained grumpy, and her body still seemed sore. In fact, if I just pointed to her sides, she would pin her ears.

By May of 2011, Renton and I had exhausted the obvious diagnoses that could be made on the farm. He suggested I take her to Michigan State University’s large animal clinic for a more complete exam. Two internists, a back specialist and a physical therapist saw her there, and together they performed a series of exams so thorough it took nearly two days to complete.

The only obvious problem they found was mild gastric ulcers, although the physical therapist also noted that Jodie’s back was oddly dipped. She wasn’t swaybacked, but it seemed as if her back muscles were weak and possibly strained by her extra weight. We were sent home with instructions to continue the ulcer treatment, begin a routine of exercises, such as belly lifts and carrot stretches, designed to limber and strengthen her back muscles, and have Jodie lose 100 pounds.

I faithfully did Jodie’s back exercises daily but saw little improvement. When I massaged or manipulated her back, she would crankily bite the cross ties. I was beginning to think that I would never be able to ride my poor mare again, but even more distressing was the thought that she’d always be uncomfortable and unhappy.

Finally, an answer
Over the Fourth of July weekend, I found myself searching the Internet for any situation that sounded even remotely similar to Jodie’s. As I clicked from one false lead to the next, I grew increasingly despondent.

Then, suddenly, I was reading a description of a horse who sounded remarkably like Jodie. This horse had suddenly turned cranky with no obvious physical reason. The owner, like me, hadn’t wanted to give up and eventually got a diagnosis: polysaccharide storage myopathy (PSSM).

This was one of the muscle disorders Renton and I had discussed briefly a year ago, but we’d decided that Jodie did not fit the profile. Well, neither had this horse I was reading about.

I immediately called Renton to tell him what I’d read, and he agreed it was worth a shot to have Jodie tested, even if the results came back negative. Currently, researchers have described two forms of this disease---PSSM Type 1, which has been linked to two specific genetic mutations that can be tested for, and PSSM Type 2, which is diagnosed by a muscle biopsy. Both tests are available only through the University of Minnesota, where much of the research on this disease has been done.

Which testing approach is recommended---the genetic test or the muscle biopsy---depends on the breed of horse. For Quarter Horses, the Minnesota researchers suggest doing the genetic test first, and by the end of the afternoon, I had received instructions via email on how to pluck mane hair and send it to the lab. Three days later I had an answer: Jodie had PSSM.

In the meantime, I’d been doing plenty of reading on PSSM, starting with the University of Minnesota’s website. I learned that many Quarter Horses, as well as more than 20 breeds, carry a genetic mutation that causes this disease (PSSM 1). Other light breeds, including Arabians and Thoroughbreds as well as some Quarter Horses, may also develop PSSM without carrying the mutated gene (PSSM 2).

Both forms of the disease affect the way muscle cells absorb, store and use the sugars they burn for energy. In horses with PSSM, the muscle tissue pulls a sugar (glucose) out of the bloodstream faster than in normal horses, according to the Minnesota researchers. The genetic mutation for PSSM, GYS1, results in overproduction of the storage form of the sugar, called glycogen, in the muscle cell. As a result, abnormal amounts of glycogen, as well as another abnormal sugar (polysaccharide), tend to accumulate in the cells. One reason for this, according to their research, is that the abnormal GYS enzyme that produces glycogen is very sensitive to insulin, a hormone released when a horse eats carbohydrates, which stimulates the muscles to take up more sugars and make more glycogen.

Horses who have inherited either one or two copies of the gene mutation may develop episodes of tying up (exertional rhabdomyolysis): painful, severe muscle stiffness and cramping in the hindquarters, usually after exercise. The muscles will feel very hard to the touch, and affected horses will resist moving their hind feet. In severe cases, the urine may be dark, brick-red or coffee-colored---a sign that muscle cells have been damaged and released proteins into the bloodstream. These proteins can damage the kidneys.

Fortunately, however, some horses like Jodie may have milder muscle pain, which is why I’d never seen signs that obvious. The downside, of course, was that her muscle stiffness and soreness were so subtle that it took
us nearly a year to figure out what the problem was.

But there was good news, too. Even in severe cases of PSSM, episodes of tying up can be prevented with careful attention to the horse’s diet and exercise. Because meals rich in starches and sugars cause insulin spikes, diets based on grass hays, with no added grains, are recommended for these horses.

Jodie got barely any grain at all, so the source of the sugars in her diet could only be our lush pasture and hay. I immediately put a muzzle on Jodie to keep her from eating any grass at all, switched her to a low-nutrient grass hay and began feeding a low-sugar, high-fat concentrate specially formulated for PSSM horses. Within two weeks she was moving much more comfortably and no longer snapped at anyone who tried to touch her.

But she still wasn’t entirely comfortable. After consulting with Renton and the University of Minnesota, I decided to discontinue the grain mixture because, frankly, Jodie didn’t need the extra calories. Within another week, her demeanor improved even more.

Regular exercise and as much turnout as possible are also recommended for horses with PSSM. This helps the muscle cells to continuously burn off the stores of glycogen they accumulate.

Jodie was already on 24-hour turn-out, but I continued doing the back exercises, and I noticed that she was beginning to lift her back and stretch more comfortably when I asked. I switched from using carrots, which are high in sugar, to celery as a lure to move her head and neck. Eventually, her topline filled in as her muscle tone and strength improved.

Once Jodie was moving comfortably, the next phase of the plan was to begin working her under saddle again. I’ll admit I was a bit anxious when I got back on her, but because she was no longer in pain, she was her old, sweet self. We hit the trails again, starting at a walk, then added short stretches of trotting. But to me it all felt as if we were flying. I cried tears of happiness the day we finally cantered and hopped over a small log.

Jodie’s PSSM wasn’t apparent when I purchased her because of the sparse fields at her previous home. Only as the sugar levels increased in our pasture over the spring and into summer did the problem arise. This past winter, the weather wasn’t cold enough to convince me the grass was dormant until mid-December, so I left Jodie’s muzzle on until then. I’ll put it back on the moment the days start to warm up again this spring.

I’ve also made one other management change. Knowing just how sensitive Jodie is to sugars and starches, I now have each batch of hay I buy tested for both. This is a lot of work, but everyone who knows Jodie knows it’s worth it. In fact, my wonderful husband even made me a hay corer for Christmas, allowing me to easily pull hay samples from the center of the bales. It was the perfect gift.