According the AAEP, colic is the # 1 cause of death in horses. Impaction colic is the blockage of the gastrointestinal tract by solid material, usually feed or hay.
The equine digestive tract is approximately 100 feet long. The intestines make several hair pin turns, making it difficult for large amounts of dry hay to pass through. Insufficient water consumption can exacerbate the issue because water helps lubricate the intestines and aids in moving feed through the system.
The risk of impaction colic typically increases in the winter months because hay consumption typically increases in the winter. Hay contains about 20% less water than grass making it more difficult to digest than fresh, green grass. Large mouthfuls of hay in combination with inadequate water intake can lead to disaster.
An Ounce of Prevention is Worth a Pound of Cure
In order to help prevent hay impactions, slow feeding and increased water intake are a good place to start. When left for hours without hay, many horses will eat too quickly when they receive their next ration and colic as a result of big, dry, masses of hay obstructing the intestines. Slow feeding helps provide a consistent supply of hay and turns off the brain's "survival mode" mechanism which is what makes many horses inhale large mouthfuls of hay. Slowing down consumption and providing forage 24/7 will help prevent not only impaction colic, but ulcers as well.
Water is key in preventing impaction. Horses drink 8-12 gallons of water a day and sometimes more during the winter. Clean water should always be readily available. Providing a plain white salt block will encourage your horse to drink more water in order to keep dry matter moving smoothly through the digestive tract.
In addition to proper diet and water consumption, regular exercise and deworming will also help prevent colic. Turnout provides movement which naturally aids digestion. By keeping worms in check, the digestive system will function much more effectively and reduce the chances of obstruction.