by Catherine Hall DVM
What comes to your mind...sandy beaches, cool ocean waves, days spent at the lake. For us as equine veterinarians, when we hear sand, we may also think of all the happy places we see sand, but always have thoughts of horses eating sand in the back of our minds. This can result in a horse colicking, a condition known as sand colic.
Most horses do not just stand around and eat sand, but if their feed falls to the sandy ground, they have a lack of food, boredom sets in, or they are not getting adequate minerals, they are likely to consume sand.
Sand colic can be very detrimental, especially if it's not caught early or measures are not taken to prevent the ingestion of sand.
Why do horses have problems from eating sand?
The horse, as we all know, does not have the most logical gastrointestinal (GI) tract. Like humans, the horse's GI tract is broken down into the small intestine and large intestine. But the horse's large intestine is broken down further into the cecum, large colon and small colon. The large colon is then further divided into the left and right dorsal and ventral colons...are we all confused by the similar sounding terms yet? Food travels from the stomach to the small intestine then enters into the cecum where fermentation of forage material and removal of water begins. From the cecum, food is moved into the very spacious ventral large colon, then the food must make a sharp 90 degree turn upwards into the more narrow dorsal colon. This is the area where most impactions occur since we are going from a large diameter part of the intestine to a considerably smaller diameter part of the intestine. The ventral colon is where sand likes to settle out of the food due to its weight being heavier than everything else. Over time, the sand will continue to settle to the point of causing an impaction itself. Due to the weight of the sand, it is very difficult for it to make the upward journey into the dorsal colon.
When the sand accumulates, it causes the colon to become very heavy. The weight and pressure, along with food material not being able to pass can cause the horse to begin to show signs of colic. As the colon continues to fill with sand, the colon will become pushed against the abdominal wall. The weight of the colon against the abdominal wall call lead to a pressure necrosis, or dying of the tissue. This can then lead to more pain and continued signs of colic.
The sand in the colon will also cause a large amount of irritation which could further slow the movement of the GI tract. Slowing things down will allow the sand more opportunity to settle in the colon and also lead to signs of colic in the horse.
There are several ways to diagnose that your horse is colicking because of a large quantity of sand accumulation.
1. Fecal floatation/glove test: Several fecal balls are taken into a rectal sleeve, water is added about half way up and then the fecal balls are broken up in the water. The sleeve is tied at the top and hung. Over several minutes, the heavier sand particles will settle into the fingers leaving the lighter grass material floating. This is an easy way for us to test for sand in the field.
2. Listening to the abdomen: If there is enough sand in the large colon, when listening with a stethoscope one may hear noises which sound like waves in the sand at the ocean.
3. Radiographs: Abdominal radiographs (or X-rays) can be taken. These have to be taken at facilities which have higher power equipment which will penetrate the large equine abdomen. Sand will be visible on the radiographs in the large colon.
If sand in the large colon is suspected, the initial treatment is to give the horse a large quantity of psyllium. Psyllium is a fiber source which also acts as a laxative. When mixed with water, it forms a gel which coats both the intestinal tract and the sand, which helps the sand to move through the GI tract more easily. There is also newer research which has shown that using psyllium along with a probiotic is more beneficial in getting the sand out of the large colon. Probiotic's are thought to help maintain the naturally occurring microbes in the GI tract and keep it functioning properly by helping with the increase in inflammation. The studies using psyllium with a probiotic produced a larger quantity of sand in the feces during treatment than using psyllium alone.
If we are unable to remove the sand with psyllium, or the horse continues to remain painful and show signs of colic, the horse may need to have surgery to remove the sand. The large colon is opened and the sand manually removed. These surgeries tend to have a good success rate.
The biggest key to prevention is to keep the horse from ingesting sand. Ways for prevention include:
1. Feeding the horses off ground, or on the ground with mats underneath
2. Making sure there is good quality pasture to graze
3. Keeping horses off of or limiting time to sandy areas
4. Feeding a diet high in bulk
5. Feeding psyllium daily for one week a month every month
6. Performing regular fecal floats for sand if feeding in sandy or overgrazed areas
We hope this is helpful in providing information about the problems that sand can cause in horses. If you live in a sandy region of middle Georgia, or have more bare pastures, we hope there are some helpful ideas to help you prevent your horses from over-consuming sand.
For more information about your horse visit our website at www.equineservices.com. You can find a library of all of our previous newsletters under the Newsletter tab. You can also learn more about your horse, cases we are seeing and current events on our Facebook page.
If you have questions or concerns about your horse please feel free to call us at 478-825-1981, we love to talk about horses!