Sand Colic in Horses

The ingestion of sand (and/or dirt) can lead to multiple health issues with horses. The accumulation of sand in the digestive tract of the horse can cause chronic diarrhea, weight loss, and colic. Sand Colic is where sand can accumulate in a horse’s digestive system and cause either irritation, inflammation, and/or an impaction colic. Surprisingly, sand colic is a leading cause of death in young horses in certain parts of the United States.

How Can Horses Get Sand Colic?

Sand colic occurs more often in areas where there are sandy soils. This is most seen in coastal areas around the United States. Outside of coastal areas, you’ll find sandy soil in states such as Texas, Michigan, Wisconsin, Minnesota, Nebraska, and Utah. Estimates are that nearly 8% of the United States is covered in sandy soils.

In regions with less sandy soils, it is estimated of all colic cases that only 5% are caused by sand accumulation in the gut of the horse. However, in these coastal areas or in regions with sandy soils, the estimates can be as high as 30%.

The most common cause of sand accumulation in the digestive tract of horses are those that are fed on the ground. Hay or horse feed fed directly on the ground in areas with sandy soils puts these horses at greater risk. As they pick up the feed with their very tactile lips, horses will also pick up sand and/or dirt. Additionally, if feed is put on a small feed pad or in a small feeder, feed can get pushed or knocked off into the sand and horses will ingest sand when eating them off the ground.

Another contributing factor for sand colic is when horses are kept on poor quality pastures. When plant availability is low, horses will graze the plant down to near the soil. Under conditions with poor quality pastures, horses will tend to pick up soil as they graze. They also can accumulate sand in the gut by drinking water with sediment in it.

Signs of Sand Colic in Horses

Rather than pass all the sand into their feces, sand can begin to accumulate in the gut of the horse. Generally, the sand will accumulate in the large colon. This can result in impaction or also result in a twist (volvulus) and displacement of the large colon. Signs of sand colic are very similar to any other bout of colic and can include:

  • Abdominal pain. Often horses will nip at their sides with colic and can be seen with raised tufts of hair along their abdomen.
  • Abdominal distension.
  • Diarrhea.
  • Weight loss.
  • Distress with rolling, pawing at the ground, groaning, and sweating.

Another way to evaluate a horse’s risk to sand colic is to check their feces. Sand will be present in horse feces, which can either be observed directly or through dilution. Fresh feces not contaminated with ground material can be diluted in water. For example, placing fresh feces in a bucket and mixing will help free up any sand. Then if any sand is present it will settle on the bottom of the bucket or other holding vessel used.

Finally, if you are concerned with sand accumulation in your horse, it is always recommended to discuss this with your veterinarian. They can help check your horses’ feces or conduct their own evaluation.

How Horses Are Treated for Sand Colic

From the data we have, about 5% of all horses will suffer a bout of colic every year. As mentioned, of these, and depending on the area of the United States, up to 30% of all colic cases can be due to sand accumulation in the gut of the horse. We also do know that most colic cases are medical in nature and need immediate treatment from a veterinarian. However, of the most severe cases of colic, only a costly surgery will help the horse survive.

In one study of sand colic cases that required surgery, the veterinarians found sand impaction in multiple locations of the digestive tract of the horses. Of these horses studied, 10% were euthanized during surgery. Of the remaining 90% of surgical cases, nearly all went on to recover and had a 100% recovery rate 1-year after surgery.

Preventing Sand Colic in Your Horses

The first step in prevention is to identify what type of soil your horses are kept on. If you are having difficulty, you can contact your local extension office and they can provide you with advice. It is also worthwhile to have a discussion with your veterinarian and ask them about the colic cases they are observing in your area, as well as the cause.

One of the most important tips for preventing sand colic is to feed your horses off the ground. There should be multiple types of hay feeders available to you in your area. The same advice extends to their horse feed. If ground feeders are used, placing large mats under the feeder is also recommended. You will also want to ensure your horse’s water supply is always clean, fresh, and free from any debris or sand/soil.

Pasture quality is also a contributing factor to preventing sand colic. Fresh grass has a high moisture content, which helps soften the feces and improves gastric mobility of the equine digestive tract. High quality forage also helps improve the quality of the hindgut microbes and overall hindgut health. If feeding hay, increased turnout time also helps with gastric mobility.

Feeding psyllium is a management strategy often employed in the hope it can help reduce sand accumulation in the horse’s digestive tract. Psyllium is a plant that produces a husk that is a source of soluble fiber for the horse. If used, it is very important to remember to feed it dry. This is because once it becomes wet, as in the digestive tract of the horse, it swells and becomes gel like. It is thought that this gel will pick up any sand in the gut of the horse to pass in the feces.

The evidence for psyllium is still under debate. Limited studies have shown some efficacy in helping to clear sand from the horse’s gut and often the amounts fed are much higher than those recommended in commercial supplements. Most studies have shown that it has no effect. Further research is ongoing with testing of individual products and their effectiveness in horses. There aren’t reports of adverse events from feeding psyllium, so it can be used as part of a holistic approach to preventing sand colic, but should not be relied upon as the sole intervention.  

Take Home Message

The saying goes, “an ounce of prevention is worth a pound of cure.” This holds true for horses under risk of sand colic. It is critical that you know what types of soil your horses are housed and fed on. If you determine your horses may be at risk, then ensuring their feed is up off the ground, or, at minimum, fed on a large mat, can go a long way in preventing sand colic.

References

Hassel, D. M. et al. 2020. Evaluation of fecal sand clearance in horses with naturally acquired colonic sand accumulation with a product containing prebiotics, prebiotics, and psyllium. J. Equine Vet. Sci. 90:102970.

Rood, K.A. and C. Tebeau. 2011. Sand colic: Risk factors, detection, treatment, prevention. Utah State University Extension Publication. AG/AnimalHealth/2011-05.

Granot, N. et al. 2008. Surgical management of sand colic impactions in horses: a retrospective study of 41 cases. Australian Vet. J. 86:404-7.
Article By: Chris Mortensen, Ph.D.
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