It may not be the most convenient or cheapest option, but repeated naso-gastric tubing done in a hospital setting is the most effective method for clearing sand from a horse’s digestive tract, according to a new study from Finland. 

A horse who grazes on sandy soil can develop accumulations of sediment in his large colon, which can lead to recurrent colic, weight loss and diarrhea. In severe cases, surgery is necessary to manually remove the sand, but several non- invasive treatments are commonly used to prevent and clear accumulations. 

One method is feeding psyllium mucilloid, dried husks from the seed of the Plantago ovata plant that expand in the colon to a gelatinous consistency. As it passes out of the digestive tract, the psyllium is believed to carry sand with it. In the other common treatment, a nasogastric tube is used to administer magnesium sulfate (Epsom salts), which acts as a laxative.

To compare the efficacy of these methods, researchers at the University of Helsinki reviewed the records of 1,097 horses who had been x-rayed for sand in the digestive tract over a six-year period. They then focused on 246 horses whose radiographs showed areas of sand in the colon greater than 75 square centimeters and who were treated medically and were monitored radiographically. The study horses fell into one of three treatment categories: 

• those treated at home and fed psyllium daily for at least 10 days (group 1)

• those treated once with psyllium or magnesium sulfate delivered by a veterinarian using a nasogastric tube, and then fed psyllium at home for 10 days (group 2)

• horses kept in a hospital for three to seven days and treated there daily with psyllium and/or magnesium sulfate (group 3) 

“Horses in group 2 were initially given psyllium or magnesium sulfate or both depending on the clinician’s judgment,” says Ritva Kaikkonen, DVM. “In group 3 there were some horses who had high magnesium levels or very loose feces so some tubings were done without magnesium sulfate and some were given only magnesium sulfate depending of the clinical status of the horse.”

Follow-up radiographs were also taken for each horse. If the horse was managed at home, the radiographs were taken within 40 days of treatment and those in the hospital were radiographed within eight days. If the second radiograph indicated the sand area had decreased to less than 25 square centimeters, the accumulation was con- sidered resolved. 

The resulting data showed that group 3, horses who were hospitalized and underwent repeated tubing, had a much higher percentage of resolved cases, with 91 of 170 horses (53 percent) clearing sand. In contrast, the success rate in group 1 was 24 percent and in group 2, it was 21 percent. Kaikkonen says the effectiveness of hospitalization with repeated nasogastric tubings could be attributed to a few factors. “Horses usually do not eat magnesium sulfate [so it needs to be delivered via nasogastric tube]. With that method, you can get a large bolus0 at once. Administration technique seems to have an influence, but based on previous studies we know that magnesium sulfate and psyllium in combination seem to be most effective. Another factor may be also that horses in the hospital did not have continued exposure to sand.” 

Owners of horses at risk of sand colic are wise to consider the possible limitations of various treatments, says Kaikkonen: “We see lots of horses who are given psyllium at home but with no effect. So I would advise the horse owners not to trust blindly that feeding psyllium is the solution. At the very least, the horse’s environment should be controlled to prevent the access to sand.”

Reference: “Comparison of psyllium feeding at home and nasogastric intubation of psyllium and magnesium sulfate in the hospital as a treatment for naturally occurring colonic sand (geosediment) accumulations in horses: a retrospective study,” Acta Veterinaria Scandinavica, October 2016

This article was originally published the March 2016 issue, Volume #474 of EQUUS magazine