Question
What is sand colic and how can I safeguard my horse from it?
Answer
The pain resulting from an accumulation of sand in the digestive tract that prevents normal passage of ingesta is called sand colic. As in other types of colic, the first sign of this ailment is usually gastrointestinal distress and inappetance.
Other signs include fever, depression, frequent lying down, pawing, rolling, and possibly thrashing. One sign that often forewarns of sand colic is chronic diarrhea that usually progresses in severity over several days or weeks.
Sand gains entrance into the gastrointestinal system inadvertently when horses overgraze sandy-soil pastures or are fed from the ground. Horses that are chronically underfed will likely procure more sand from the environment because they will scavenge for every stray stem of forage or kernel of grain. Because of the weight of sand, it does not advance normally though the colon or cecum of the large intestine and usually settles in the hindgut. Veterinarians can often determine if sand is present in the large intestine through ultrasound, radiography, stool samples, or occasionally abdominocentesis.
The key to preventing sand colic is astute management. Of foremost importance is where a horse is fed. Feeding systems designed specifically to reduce sand ingestion should be engineered. Instead of feeding horses off the stall floor, for instance, place large rubber mats beneath a manger or hanging haynet. The horse will consume the majority of the hay allowance from the haynet. Should he decide to delve into the fallen stems and leaves, he will be plucking them from a sand-free surface. In pasture situations, hay feeders can be secured on rubber mats or concrete or asphalt pads.
Textured feed and pellets should also be offered in an appropriate feeder, ideally one large enough to catch any grain that falls from the mouth. As with the hay feeders, these tubs or containers should be placed on a hard surface that is cleaned regularly.
In terms of a supplement that may rid the gastrointestinal tract of sand, there is only one that may be of benefit. Husks of the minute psyllium seed are often fed as a sand colic preventative. Such products come as pellets, powders, or granules and are top-dressed to the feed. Psyllium is thought to improve intestinal motility and remove sand by a process known as agglutination, which causes sand granules to bind to psyllium and move through the gut normally.
Occasional feeding of psyllium is recommended more often by veterinarians than daily feeding. Dosing once a week or for several consecutive days a month is thought to be more advantageous because the gastrointestinal tract will not have time to become accustomed to psyllium, thus reducing its effectiveness in clearing sand. Daily psyllium intake may also prevent proper absorption of some nutrients from the intestinal mucosa.
The scientific community does not agree on the benefits of psyllium. Numerous studies conducted on psyllium-dosed horses have ended in mixed results; some researchers have found psyllium useful in clearing unwanted sand, while others have encountered only negligible results.
