Sand: More Concerns Than Colic

Perhaps the thought of sand conjures up images of tropical beaches, azure waters, and pure relaxation. But tie that word to colic and you have anything but an idyllic scene. Sand colic, like other variations on the colic theme, can cause anything from mild discomfort to death. Knowing what to look for, understanding treatment recommendations, and putting sound prevention strategies into practice can help keep your horse safe, and your visions of sand returning to paradise.

More Concerns Than Colic

Trouble starts when horses ingest sand or similar matter, including dirt, gravel, or decomposed granite. In general, they don't gobble it down intentionally. Instead, they swallow dirt attached to grass roots when grazing or they might pick it up when looking for forage in dry lots or overgrazed pastures. Dirt can also mix in with feed when horses eat meals off the ground.

Typically, the sand (or other matter) passes through the horse's stomach and small intestine fairly easily. In fact, a small amount of sand can pass through the entire digestive system and cause no harm. But, in cases that lead to colic, sand tends to settle in the right upper (dorsal) colon, says Diana M. Hassel, DVM, PhD, Dipl. AVCS, assistant professor of equine emergency surgery and critical care at Colorado State University. Often, the ventral portion of the colon is the accumulation point. Hassel says that's probably because the sand weighs down the dorsal colon, displaces it, and it lies against the lower body wall.

As sand accumulates, it creates an obstruction in the digestive tract, disrupting normal gastrointestinal activity. Gas can build up behind the obstacle, causing distension and pain that can lead to muscle spasms and slow intestinal motility.

In short, your horse colics.

However, in this scenario colic can be just the beginning of your worries. The sand can also abrade the mucosal lining, acting much like sandpaper on your skin. This irritation, combined with the sand, can reduce the intestines' ability to absorb water and other nutrients. In addition, says Hassel, "It is possible that the intestinal wall can rupture from a severe, long-standing sand impaction, since the intestinal wall becomes damaged from the chronic irritation."

Development and Diagnosis

Sand colic doesn't develop overnight. It can take weeks or months of accumulation to create a load that noticeably affects your horse. The first visual signs might be as vague as "he's just not doing well," changes in appetite or eating habits, or differences in attitude, behavior, or performance. An afflicted horse might experience mild, recurring bouts of colic, and could exhibit standard colic symptoms such as restlessness, kicking at the belly, and excessive sweating or yawning.

"Mild diarrhea, recurrent colic, and low-grade fevers of 101-102� (F) might be associated with sand accumulation," says Hassel. In fact, persistent diarrhea has been reported to develop in 35% of afflicted horses before they show other signs of pain (see "Ridding Sand from the Diet").

To begin differentiating a sand colic from any other type of colic, your veterinarian might look for telltale clues around the barn, such as sandy matter in water buckets, sandy pastures, and dirt feeding areas. There are also several diagnostic tests and tools at your veterinarian's disposal.

Fecal sedimentation test Hassel says to perform this test, collect manure in a rubber glove or other container. Add water, mix, and allow it to settle. Pour off the fluid and see how much sand is left in the container. "Horses with sand (in their gut) may be negative with the fecal test if the sand is not moving through the intestine," Hassel explains. "But those with a fair bit of sand present (in the glove) likely have a problem worth investigating."

Radiographs Hassel considers X rays the best diagnostic tool for identifying sand accumulation. "Unfortunately, this requires very specialized equipment that is typically found only in large referral institutions and practices," she notes.

Auscultation Your veterinarian can listen to your horse's gut through a stethoscope placed at several points along the abdomen. Sand makes a telltale sound that some veterinarians have likened to the tide rolling in on a sandy beach. However, lack of that distinctive sound doesn't necessarily indicate an absence of sand, so this test is not always definitive.

Ultrasound Hassel notes that sand cannot be visualized using ultrasound, but some ultrasonographic features can point to the presence of sand. For instance, an ultrasound study at Auburn University indicated that sand in a horse's intestines shows up as a textureless, homogenous gray pattern distinguishable from gas or feces (which present a textured appearance). Hassel believes ultrasound can be a useful diagnostic aid when used with other techniques, particularly when radiography is unavailable.

The Psyllium Debate

Once your veterinarian has diagnosed sand colic, treatment depends on severity of the problem. In relatively mild cases, veterinarians often recommend psyllium, which comes from the husk of the psyllium seed (also known as fleawort). Psyllium is available in many commercial preparations, including pellet and powder forms. Psyllium treatment typically involves stomach tubing the product for several days, followed by a few weeks of twice-daily supplementation with feed.

There is some debate regarding just how psyllium works. Proponents of the treatment say it lubricates the horse's gut, helping the sand slide through the system. Or it might stimulate intestinal motility and help the intestines retain fluid, which again helps move the sand along.

A 1998 University of Illinois study showed that there was no significant difference between ponies treated with psyllium and those not treated. However, a Finland study found that psyllium laxatives did help 13 of 14 horses to eliminate sand. Research at Colorado State University showed that psyllium therapy treated chronic diarrhea associated with sand accumulation.

"My clinical experience would argue that psyllium supplementation is beneficial in assisting with the removal or prevention of accumulated sand in the colon," Hassel says.

"The studies that showed no effects of psyllium on clearance of sand were based on experimental situations that do not mimic the clinical situation," she adds. "In reality, horses likely accumulate sand over a period of weeks to months or even years, and this sand likely impacts motility patterns in the large intestine and causes chronic irritation in the intestinal wall. In the experimental studies, sand was added to the cecum, where it almost never accumulates clinically, at a single time point in healthy ponies with normal intestinal motility patterns."

Other Options

Tubing with Epsom salts (MgS04) is another treatment option, apparently increasing water in the intestine and helping flush sand from the colon. Hassel believes that it can be particularly effective in combination with psyllium.

Some people believe that wheat bran can also help treat sand colic, perhaps because bran is considered a laxative. However, Hassel agrees with most other veterinarians who say that wheat bran is not likely to have any beneficial affect on sand accumulation in the horse's gut.

The Risk of Surgery

When sand accumulation is not caught soon enough, or when the horse doesn't respond to treatment, surgery is required. During surgery, a portion of the horse's large intestine is pulled out of the abdomen and opened. The veterinarian then flushes out the sand, stitches the incision and replaces the intestine in the abdomen.

While the surgery is fairly straightforward, the veterinarian must be careful to prevent sand and intestinal contents from contaminating the horse's abdominal cavity. A similar risk, says Hassel, is that horses whose intestinal walls have become damaged from the chronic irritation of sand might experience a rupture when the surgeon removes the impaction. In either case, the contamination can lead to an uncontrollable, fatal infection.

At one time, surgery for sand colic had a survival rate of 60-65%. Today, Hassel believes the figure is considerably higher. "With the use of products such as Biosponge (a clay that binds toxins and reduces diarrhea), we are reducing post-operative diarrhea, which is likely the biggest factor in survival of these horses," she says.

Hassel adds, "Horses with sand colic have a much better prognosis than those with any other type of intestinal disease associated with strangulation of intestine, such as colon torsions or small intestinal strangulations, but probably have a lower prognosis than horses with simpleimpactions or displacements that do not have irritation of the intestinal wall."

Overall, comments Hassel, horses treated successfully, either surgically or medically, for sand colic have a very good prognosis for a return to a normal life and diet. "The intestine has a remarkable ability to return back toward normal if the damage wasn't excessive," she says.

Sand-Free Strategies

As is the case with so many health care issues, prevention is nine-tenths of the sand colic cure. And, says Hassel, "The most important component to prevention is limiting access to dirt or sand."

To achieve that end, try these strategies:

  • Feed in bins off the ground.
  • Make sure the feeding area has a non-dirt surface, such as rubber mats, concrete pads, or straw. This is important even when using feed containers, since horses often pull hay out of bins and scatter it on the ground.
  • Manage pastures to avoid overgrazing so the horse is less likely to slurp up dirt while searching for grass.
  • Make sure your horse's diet includes sufficient fiber and forage, and consider feeding before turning your horse out, particularly if you turn out in a dry lot. This can reduce a horse's tendency to nuzzle along the ground searching out food. In addition, adequate fiber intake contributes to overall gut health.
  • Offer free-choice access to a mineral block. "Although not proven experimentally to my knowledge, (this) may be indicated in horses prone to eating dirt/sand since it is possible that these horses may be lacking some minerals in their diet," says Hassel.
  • For horses at risk or already showing mild signs of sand accumulation, discuss psyllium use with your veterinarian. In general, veterinarians recommend that you not use psyllium on a daily, ongoing basis. Instead, you might add a cup or two to your horse's diet daily for a week, then repeat the program every four to five weeks.

Take-Home Message

Sound prevention strategies teamed with knowledge of signs of sand colic and treatments can give you the upper hand when it comes to kicking sand colic out of your barn--and making sure that your horse stays healthy and able to enjoy a good gallop along the beach.

Who's At Risk?

Obviously, horses living in dry, sandy areas are at greater risk for sand colic than those living in lush, green fields. But it can crop up in any region of the country. "We rarely see severe sand colics at Colorado State University compared with northern California, Arizona, and Florida," says Diana M. Hassel, DVM, PhD, Dipl. AVCS, assistant professor of equine emergency surgery at Colorado State University. "However, small sand accumulations are very common."

When it comes to age, breed, and gender, sand colic knows no boundaries. However, some veterinarians feel that foals might be somewhat more susceptible because of their smaller digestive tract and their tendency to taste-test all kinds of foreign matter.

Some horses might be more prone simply due to differences in gastrointestinal motility, their ability (or inability) to excrete ingested sand, and their tolerance for having extra matter in their gut. Unfortunately, these aren't traits you can see from the outside, so applying good management practices remains your best path to warding off sand colic.--Sushil Dulai Wenholz

About the Author

Sushil Dulai Wenholz

Sushil Dulai Wenholz is a free-lance writer based in Lakewood, Colo. Her work appears in a number of leading equine publications, and she has earned awards from the American Horse Publications and the Western Fairs Association.

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