Enteroliths (or Intestinal Calculi) are formed in a horse’s GI tract and can cause GI obstruction and pain (i.e. colic). Enteroliths consist of struvite, which is a substance composed of magnesium ammonium phosphate. The struvite builds up around a nidus, such as a piece of metal, cloth, a pebble, or some other foreign object consumed by the horse, and are then passed as crystals or stones in the stool. Horses passing a few walnut-sized enteroliths is common, but more than that can be a cause of concern. Here are some ways to help your horse stay enterolith-free.
According to the National Research Council horses living in the Southeast (primarily Florida and Louisiana) as well as western states like California and Nevada are at greater risk of forming enteroliths. When a horse consumes a nidus and the GI environment is in a more alkaline or basic state, rather than acidic, this allows the struvite to form and construct an enterolith around the nidus. Once the enterolith becomes too large to pass out of the system naturally it must be removed surgically, which can be costly for owners and very stressful for horses. Enterolith formation can occur in any horse at any age, and have been seen in horses as young as 11 months as well as geriatric animals, and in any breed. Some breeds, such as Arabians, Arabian crosses, Morgans, American Saddlebreds, and Miniatures have been reported to have a higher prevalence of enteroliths but in the right environment any horse can be at risk. Additionally, there does seem to be a possibility that enterolith formation can be heritable according to a study by Hassel et al. done in 1999 that reported a high prevalence of enteroliths among siblings.
courtesy Arenus
enterolith 2
stones found in horse
With this in mind, here are a few nutrition tips for enterolith prevention:
Decrease legume hay that may create a more basic GI environment.
Certain legume hays like Alfalfa are fantastic protein sources; however, they also contain a higher amount of calcium and other minerals that may create a more basic environment in the GI tract. While this is very helpful for ulcer prevention it can be problematic for horses that are prone to enterolith creation. Additionally, legumes can contain a higher amount of magnesium which is an ingredient in struvite.
Exclude wheat bran from the diet.
Much like legume hays, wheat bran can create a more basic environment in the GI tract. Reduced acidity of the GI tract fosters an environment where struvite forms. Legume hays and wheat bran both provide the building blocks for struvite, and if a horse is prone to enteroliths, it can run into problems that are not easy to fix.
Add apple cider vinegar.
The National Research Council recommends adding one cup of apple cider vinegar to the feed ration twice (ponies used 1/2 cup) daily to help reduce the basic environment created in the GI tract and mildly increase the acidity of colonic contents.
Give your horse daily pasture turn-out where possible.
Studies have shown that daily turn-out on pasture has reduced the risk of enterolith formation. Scientists have not determined whether it is the increase of fresh grass or the exercise-induced by pasture turn out, however it is apparent that turn out on fresh grass is beneficial to horses suffering from enterolith formation. It is important to note that they must be turned out on a healthy grass-laden pasture; turning out on a dry lot or a very sandy soil could actually cause more enterolith-related problems.
Commit to a monthly psyllium regimen and a daily pre and probiotic regimen.
Psyllium and pre- and probiotics can help modulate the motility of the GI tract. Probiotics keep things moving at the correct pace in the hindgut, preventing slow-downs by hindgut inflammation and other issues. This reduces the possibility of a nidus and struvite having the time to form. Additionally, there have been cases where small enteroliths are able to be expelled before they become large enough to necessitate surgical removal. Psyllium and pre- and probiotics can be very beneficial for proper motility in the enterolith-prone horse.
courtesy Arenus
enterolith
Enteroliths can cause significant GI problems and may result in colic issues or, in the worst cases, emergency surgery. Taking the measures outlined here can prevent enterolith formation and proactively help clear them from the system while they are still small and less likely to cause impaction and abdominal pain. Taking preventative healthcare for our horses seriously can not only help them live longer, happier lives, but also help us as horse owners sleep better at night and enjoy longer, more fulfilling relationships with our equine partners.
Brady Karren is the Equine Nutritionist for Arenus makers of Assure and Sore No More and can be reached at brady.k@arenus.com
Photos by Evon Harrison http://www.myhearthorse.com/how-i-finally-ended-the-six-year-battle-with-sand-in-my-horses/