A study from Finland suggests that some horses develop sand colic not because they accidentally ingest dirt with their meals but because they actually like to eat soil.
University of Helsinki researchers conducted an online survey of owners whose horses had been radiographed at some point to check for accumulated sand. Each respondent was asked a variety of questions including which clinical signs prompted a call to the veterinarian, how much sand had accumulated in the horse’s gut and how the horse was managed at that time. Data from a total of 447 surveys were used in the final study.
The researchers discovered that, in many cases, the veterinarian was called in because the owner suspected that sand had accumulated in the horse’s gut, and abdominal radiographs confirmed the suspicion. Diarrhea, colic and poor performance were among the signs of trouble most commonly reported by the owners.
“Most often the poor performance is subtle,” says Kati Niinistö, DVM. “The horse is not jumping as nicely as it used to, not cantering properly, or just does not want to move forward. Many times people don’t link the changes to sand accumulation, but only realize that the problem disappeared when sand was treated. If we don’t find anything special in the lameness exam, but the horse is unwilling to move and maybe not using the hind limbs as before, we sometimes take a radiograph for sand.”
In addition, the data showed that horses exhibiting signs of colic were more likely to have significant accumulations of sand in the gut than were other horses. There was also a correlation between poor performance and large sand accumulations. Horses who seemed colicky and performed poorly had the highest levels of sand.
The researchers did not find any connection between the likelihood of sand accumulation and feeding methods, housing arrangements or other management practices. Niinistö says this may be because some horses habitually eat soil.
“Unfortunately there are many horses who actively seek the soil and try to eat it, even when muzzled,” she says. “They learn to use the plastic muzzle as a shovel and push the soil into it. We are currently collecting samples to study if any of these horses have deficiencies in the trace minerals and, therefore, seek the soil.”
Interestingly, the study found that “greedy” horses---those who always ate all of their hay---had larger sand accumulations than did horses who often left some uneaten. “I am not always sure if [the problem of sand accumulation is related to] the soil, or the habit of keeping horses out most of the time during a long season without proper grass,” says Niinistö. “We have some horses who have the habit to try to find food anywhere.”
Regardless of whether sand ingestion is intentional, prevention is the best course of action, says Niinistö, who notes that sensible feeding practices can reduce the inadvertent ingestion of soil.
“I would avoid giving food from the ground, and try to give horses something to chew on---spruce or willow branches or whatever wood they like that is not toxic---if they are too fat to eat all the time,” she says. “Some horses just need to be muzzled. I would treat the susceptible horses with psyllium a few times a year, and if there is any doubt, take x-rays to confirm or rule out the sand.”
Reference: “Owner-reported clinical signs and management-related factors in horses radiographed for intestinal sand accumulation,” Journal of Equine Veterinary Science, May 2019
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