By Maia Aitken, DVM, Large Animal Surgery Intern, New Bolton Center, University of Pennsylvania School of Veterinary Medicine

[November 15, 2010; Kennett Square, PA]--As if the cold weather, hard-as-cement ground and short days weren’t enough, horse owners have another thing to dread in winter: Colic. There are varied causes of colic, really just a term for abdominal pain, but during the cold season, a frequent type of colic we see at New Bolton Center is impaction of the gastrointestinal tract, especially of the large colon. Impactions of the large colon occur when the large intestine is blocked by a mass of firm, thick, dry ingesta (feed material). Common clinical signs often begin as mild signs, including decreased manure production, decreased appetite, and dry manure. However, if untreated, horses usually begin to show more dramatic signs of abdominal discomfort including pawing, flank-watching and rolling. There are three main reasons as to why impactions occur commonly during the winter. Most importantly, horses tend to consume less water in colder weather. This may be due to a decrease in thirst or because water sources freeze over. Secondly, horses are often fed increasing amounts of concentrate and grain during the winter months, which may alter digestion. And lastly, inactivity due to confinement during the colder months may also contribute to a change in movement of ingesta along the gastrointestinal tract.

Whatever the cause, impactions are generally treated medically with a course of enteral fluid therapy administered via repeated nasogastric intubations to soften and break up the impacted feed material. Horses are usually held off feed until the impaction is resolved and may be administered anti-inflammatory medication as needed. More severe impactions may also require intravenous fluid therapy depending on the horse’s state of dehydration. The most severe impactions may require the need for surgical intervention to physically remove the impacted feed material from the gastrointestinal tract.

Horse owners can help lower the risk of their horses developing impactions by employing management changes that target the previously mentioned risk factors. The first step involves ensuring your horse has access to clean, fresh, unfrozen water at all times. Strategies to manage this task may include insulating any above-ground water pipes, purchasing water-trough or bucket heaters or even carrying hot water to thaw frozen buckets at least twice daily. In addition, providing your horse with a salt block or electrolyte bucket may encourage consumption of water. Secondly, turning out horses increases digestive stimulation, provided that they have heavy winter coats or blankets and access to shelter. Finally, when increasing your horse’s caloric intake, reach for an extra flake of good quality hay, rather than grain, when temperatures start to decline. Horses are grazing animals and rely on constant digestive stimulation to maintain a healthy gastrointestinal tract.

Any winter, be it mild or severe, will be easier to deal with if you are prepared in advance. Plan ahead, and remember that many of the wintertime woes that plague our horses may be prevented with simple management changes.