While there are several different types of colic, impaction colic is the type most often seen during winter months. Decreased water consumption is assessed to be the number one factor contributing to impaction colic. In simple terms, impaction colic is caused by a blockage that forms in the large colon, cecum, or small intestines due to a feed material obstruction. Sufficient daily intake of water is a crucial component for healthy gastrointestinal motility of the large colon in the horse. The average 1,000-pound horse requires approximately 5 – 7 gallons of water per day, and in a 24-hour period, the horse’s colon and cecum secrete and reabsorb roughly 30 gallons of fluids.
It is a common belief that horses drink less water as the temperature of drinking water approaches freezing and that they will drink more if the water provided is warmer. Researchers from the University of Pennsylvania School of Veterinary Medicine conducted a study to determine the horse’s preferences for water during cold temperatures.
The study revealed that horses drank 40% more water when the water was heated (average 60°F), but ONLY if heated water was the only available water source. If cold water (approx. 32°F) was available, horses drank almost exclusively from the cold water and drank less volume than if they had only warm water available.
Researchers also observed that all horses in the study consumed 82% of their daily water intake within three hours of feeding, regardless of whether they were stalled or in pastures during feeding times. Additionally, the study found no preference or increase in water consumption between heated water buckets or heated stock tanks.
For optimal water consumption during cold weather and to decrease the likelihood of impaction colic, provide horses with warm and prevent access to cold water. Additionally, if you use buckets, it is important to refill them at (or just after) feeding to ensure a maximum amount of water is available to the horse in the three hours immediately after feeding.
Kristula, M.A.; McDonnell, S.M. Drinking water temperature affects consumption of water during cold weather in ponies. Applied Animal Behavior Science 41: 155-160, 1994.