Horse Colic - Causes and Recovery

where the gut is not occluded and colic can resolve with routine therapy. This makes enteroliths difficult to diagnose because they are difficult to palpate rectally even when they cause colic. Depending on the size of the horse and location of the enterolith the blockage can sometimes be diagnosed using abdominal radiography Xray. Enteroliths are most often diagnosed during exploratory surgery. Several studies have shown that enteroliths are more common in California in Arabian horses and in horses over four years of age.
Enteroliths are composed of magnesium calcium and variable amounts of other minerals. Diets high in alfalfa are a recognized risk factor for enteroliths. It is believed that the combination of high dietary calcium magnesium and elevated concentrations of ammonia in the gut when protein is digested all contribute to enterolith formation. The only practical way to prevent enteroliths is to restrict or eliminate alfalfa from the diet.
The large colon can displace or move from its normal position in the abdomen and not necessarily twist. Pain still occurs due to tension on the gut or accumulation of gas. Large colon displacements tend to have a favourable surgical prognosis. An example is left dorsal displacement or nephrosplenic entrapment in which the left colon rises up over the nephrosplenic ligament a ligament between the spleen and left kidney and becomes entrapped. Many cases will need surgical correction but some resolve with medical therapy to shrink the spleen or by rolling the horse under general anaesthesia Small intestinal colic can result from gas or fluid distension obstruction of the small intestine ileal impaction or roundworms or twisting of the gut small intestinal volvulus or pedunculated lipoma in old horses.
In general small intestinal colics are more worrisome than large intestinal colics. The usual hallmarks of small intestinal colic are elevated heart rate 80 beats per minute or more gastric reflux when a nasogastric tube is passed into the stomach and severe pain that is difficult to relieve. Despite the intense pain the horse often becomes comfortable when the gastrointestinal tract is decompressed with nasogastric siphonage.
Ileal impaction is a frequent diagnosis of small intestinal colic where coastal bermudagrass is a readily available forage. Coastal bermudagrass hay has a high fibre content compared to most other forages and is more likely to cause impactions especially in dehydrated horses. Tapeworm infections and thickening of the muscular layer of the ileum muscular hypertrophy in some older horses