Impaction Colics: who, what, where, when and why?
Colic in a horse is a loosely coined term that basically defines any type of discomfort signs a horse can show. Most typically, colic signs are caused by some sort of gastrointestinal disorder. Symptoms are typically pawing, flank watching, and/or lying down and rolling. Nevertheless, some horses can simply go off-feed and become lethargic as well. Disruptions of the intestine that can cause colic can range from severe strangulating lesions, to gas build-up, and most commonly, impactions. Impaction colic is a buildup of feed material in the intestine that causes a blockage. The blockage leads to constipation-like pain rooting from pressure and spasms on/of the intestinal wall. There are areas of the horse’s gastrointestinal tract that are prone to impactions due to their hairpin bends and smaller lumen diameter such as the pelvic flexure of the large colon. Other common locations for impactions are: the stomach, the cecum and the small colon (especially in breeds such as Miniature horses). However, it is important to remember that impactions can happen anywhere along the GI tract.
Many horses that are showing mild colic symptoms are diagnosed with an impaction. Typically these horses have been noted by the owner to have decreased manure production and decreased water intake. From the veterinary side, most of the horses we diagnose and treat for impactions have a normal to mildly increased heart rate and decreased gut sounds. We might also find that the horse is dehydrated on blood work. The most effective way to diagnose an impaction is by performing a rectal examination. Blockages that are closer to the “tail-end” of the horse can be palpated by the veterinarian, although sometimes these impactions can be out of arm’s reach. Another clue from the rectal exam that can lead us to suspect an impaction is the presence of dry, firm fecal balls in the rectum. This can indicate that the horse is dehydrated. When a horse’s water intake decreases, the hydration/lubrication of their intestines decreases; this causes reduces gut motility and build-up of feed material.
Horses can be prone to decreased water intake when the weather becomes colder. Simultaneously, winter months lead to more time in the stall and less turnout which, in turn, can decrease intestinal motility. These two factors ultimately can lead to impactions. Therefore, especially in the winter months, be sure to make note of any changes in your horse’s manure output and water intake. Also, ensure they are receiving as much turnout as possible when the weather permits such. Another predisposing factor can be trailering, recent feed changes, dental problems, or internal parasites.
A brief overview of what to expect if your horse is diagnosed with impaction colic is as follows. The best way to treat impactions is fluid therapy. This can be accomplished on the farm by passing a nasogastric tube and giving the horses fluids through the tube. These fluids can range from mineral oil, to water with electrolytes and/or Epsom salts. These fluids aid in hydrating the intestine, lubricating the blockage and breaking up the impacted feed material. Most horses can recover well with one dose of fluids; but, some horses require multiple doses of fluids to relieve the blockage. In rarer cases, severe impactions can require hospitalization. When the horse comes into the clinic for an impaction they will receive frequent doses (usually every 2 hours) of fluids through a nasogastric tube. Some horses will also be placed on intravenous fluids so they can hydrate both systemically and locally within the gastrointestinal tract.
Remember, the best way to fend off impactions is by providing horses with plenty of water and lots of turnout. But if your horse begins showing signs of colic call one of our veterinarians to the farm for an examination. We are available for emergencies 24/7!