We're trying to determine the incidence of sand accumulation in the fecal matter of horses around Saskatoon because of sand-related gastrointestinal disease (SGID) — or sand colic.
SGID can occur in horses when ingested sand accumulates in their large colon — a problem that can lead to diarrhea and impaction. A horse suffering from sand colic often requires veterinary attention and sometimes requires surgery to correct a major impaction.
An indicator of sand intake in horses is the presence of sand in the horses' fecal matter. Veterinarians also use X-rays and ultrasound images to diagnose sand colic, but these methods are more costly and sometimes not available if the horse is being seen on farm.
Before taking a fecal sample from a horse, I have to don an arm-length plastic sleeve, lube up my arm and go in rectally to find the feces. We use a standardized technique to determine the amount of sand in the sample. We measure out 200 grams of fecal material and mix it into 1,000 millilitres of water in a graduated cylinder (essentially a tube with a base).
After the mixture sits for 20 minutes, the sand settles to the bottom of the cylinder while the fecal matter floats to the top of the water. The amount of sand is then measured using the marks on the side of the graduated cylinder.
Anecdotally, there's a low incidence of horses presenting with SGID at the WCVM Veterinary Medical Centre even though a number of Saskatoon-area equine facilities are built on sand-based soils. Horses that are fed hay on the ground at these barns are likely to ingest increased amounts of sand along with their feed. By focusing on sampling the barns with sandy soils, we can estimate the risk of sand colic around Saskatoon.
"The incidence of sand-related gastrointestinal disease has never really been looked at around the Saskatoon area. We know that it is a common occurrence in many states such as Texas but it is impossible to extrapolate findings from a very different geographical location and project them onto Saskatoon," says Manning, an equine field service veterinarian.
"It is important to find out what is normal in our specific location. This project is a starting point in our efforts to understand the importance of this problem in our area."
The early stages of the study have not revealed any sand in fecal samples from horses around Saskatoon. These samples were from early on in the summer, shortly after the snow had melted. The same horses will be tested again in late summer to determine if a longer exposure to sand increases the risk of sand colic.
Along with fecal samples, we also gather information about the horses including their diet, activity level, housing and medical history. Most of the horses involved in the study are quarter horses that are used for pleasure or schooling. Very few of them travel, and they primarily live in pastures, eating grass and hay. We have acquired samples from horses ranging in age from three years to more than 20 years old.
The collected information will allow us to look at the overall risk factors for SGID in horses around Saskatoon and adequately inform their owners. If there is sand, we would recommend that horse owners use a hay net or feeder versus feeding hay on the ground. Horses can also be fed a fibre supplement to help encourage the movement of sand through their system and preventing it from accumulating and causing an impaction.
Lindsay Rogers of Calgary Alta., is a third-year veterinary student who participated in the WCVM's Undergraduate Summer Research and Leadership program in 2013.