Horse Health Article - Sand Colic
With Autumn comes rain, and in Western Australia, with rain comes sand. Most West Australian horse owners know all about our sandy soils, and how this predisposes our equine population to sand accumulation, and sometimes sand impaction colic.
But why does this happen? And does the traditional “oil drench” actually do anything? How can we help to prevent sand accumulation? Read on to find out.
Why is sand accumulation common at this time of year?
As we all know, Western Australian soils are extremely sandy meaning that there is a poor ability of the soil to hold together. With the first Autumn rains, the soil is subject to surface erosion, where the sand is moistened and breaks apart more easily. It is presumed that as horses graze the new grass shoots coming through, the poor soil quality leads to the plant become uprooted, leading to sand becoming ingested by the horse.
What are the signs that my horse may have sand accumulation?
In a study done by Niinsto et al. (2022), the singular most significant signs reported by horse owners whose horses had clinically significant sand burdens were colic, diarrhoea and poor performance.
When looking at a combination of clinical signs, the horses that had the strongest correlation with heavy sand burdens had both colic signs and diarrhoea, or colic signs and sensitivity around the flank.
Image: K Niinsto et al. (2021) https://doi.org/10.1111/eve.13562
What tests should be done by your veterinarian to confirm a diagnosis of sand accumulation?
Interestingly, while many veterinarians will auscultate (listen with a stethoscope) for the presence of a “seashells” noise to indicate the presence of sand in the ventral colon, a 1989 study by Ragle et al., showed that over 6.5kg of sand must be present in the colon before it can be “heard”!!! So if your vet can’t hear sand - that doesn’t mean there isn’t any in there!
What about the faecal glove flotation test?
This is actually not a good screening test for the presence of sand in the ventral colon. Sand in the faeces shown by the presence of sand in the fingers of the glove is simply a sign of sand ingestion by the horse, but not whether there is abnormal accumulation of sand in the colon.
So how do we best diagnose the presence of sand in the horse’s colon?
The answer is with X-rays. X-rays allow us to visualise the lowermost portions of the horse’s ventral colon within the abdomen, and sand shows up as “white” compared to the normal “grey” soft tissue opacity. There has been an algorithm developed that allows us to determine whether the presence of sand is likely to be significant (i.e. causing a problem for the horse) or not.
What actually causes sand colic?
A significant accumulation of sand within the ventral colon is likely to cause colic in horses. The reason for this is likely due to the irritation of the colonic mucosa leading to “colitis.” Colitis is an abnormal inflammation of the bowel tissue, which in turn sets off a series of events leading to decreased motility of the gut. This decreased motility can cause further ingesta to become “clogged” in the bowel, leading to an impact ion. This, in turn with the pain and discomfort experienced by the horse, leads to the signs of colic.
How do we treat sand colic?
The primary treatment for any colic is to control pain, inflammation, maintain hydration of the intestinal contents, and return normal intestinal motility. Treatment for colic caused by a sand impaction is no different to any other colic = pain relief, fluids +/- ancillary treatments.
Removal of the sand should NOT be incorporated into any primary medical treatment of colic. Once a horse’s intestinal function has returned to normal (i.e. the initial colic episode has resolved), the sand impaction (i.e. the cause of the colic) can be treated.
If the horse is not able to be medically managed, sometimes horses will require surgical removal of sand and/or impacted intestinal contents through colic surgery.
My horse is no longer colicky - so how do we get rid of the sand?
Some of you may be shocked to read that recent data by Niinsto et al. (2021) shows that a one-off drench with paraffin oil + psyllium husk +/- Epsom salts was NOT effective in the removal of sand.
Similarly, treatment with either paraffin oil alone, paraffin oil + psyllium husk, or paraffin oil + Epsom salts, was NOT as effective as the combination of paraffin oil + psyllium + Epsom salts all together (given at a ratio of 1g/kg body weight). This study showed for this treatment to be effective, it should be given every day for a total of 4-7 days.
The removal of sand through this treatment was found to cause discomfort in some horses, so pain relief is also suggested throughout the duration of treatment.
Does this mean feeding psyllium for a week once a month doesn’t do anything?
According to the research, yes. Technically, feeding a horse psyllium once a month for a week does not do anything to prevent or treat sand accumulation. There is also NO evidence to suggest that constant feeding of psyllium causes the horse to develop a “resistance” to psyllium.
So will feeding your horse psyllium do any harm? The answer is no. If feeding psyllium makes you feel better about managing your horse for sand, then by all means go ahead. However, if you really want to be proactive, save the money you spend on these feeds and get your vet out to X-ray your horse for the presence of sand.
Is there any way to help prevent sand accumulation in horses?
Yes! There are a few ways you can help to prevent sand accumulation in your horse:
Always feed hay above the ground in slow-feeder nets, with a solid surface below (e.g. rubber matting/concrete). This stops horses from ingesting sand on the ground when picking up fallen pieces of hay.
If your horse is greedy (i.e. gobbles up every last bit of feed on the ground), feed your horse in a hanging bucket or a nose bag. This stops them from spilling as much of their hard feed onto the ground.
Put rubber mats down around communal feeding areas (e.g. hay rolls).
Put a grazing muzzle on your horse to prevent them being able to eat so closely to the ground, and prevent overgrazing of pastures (the longer the grass, the less likely your horse is to uproot the plant.)
If you want to know more about treatment for sand accumulation, or would like to book your horse in for a sand assessment - please don’t hesitate to contact us.