I’m confused about how to encourage horses to drink enough during the winter. I’ve heard that research shows horses drink more water in winter if it’s warm, but I can’t find information on just how warm the water should be. I have tank heaters in a trough to keep water from freezing, but is that warm enough? And how do people keep water warmer all day? If I top off a bucket with hot water in the morning, will my horse drink it before it cools enough to ice over? I’d like to follow best practices, but I’m not sure what they are.
The research you most likely heard about was done by Sue McDonnell, MS, PhD, and myself at New Bolton Center in the late 1990s. We published results from two crossover trials on offering warm water to 14 pony stallions stabled in a barn with individual tie-stalls in the winter, when ambient air temperature in the barn ranged from 19° to 41° Fahrenheit.
Studies of cold weather hydration in horses
In the first trial, commercially available bucket heaters kept water in individual buckets warm. That water temperature averaged 66.2° F and ranged from 41° to 140° F. In the second trial, the buckets were filled twice daily with tap water at 115° to 120° F. In both studies, cold water was allowed to cool to ambient temperature and averaged 32° to 33.8° F when refilled. Overall, for both trials, the ponies drank 40 percent more warm than ambient, near-freezing water. Most of the drinking occurred within three hours of feeding and water refill.
The data showed that providing hot water twice daily at feeding time was a simpler method for providing warm water to individually stalled ponies than using commercial bucket heaters. The water had cooled to the range of 68° to 95° F during the time most drinking occurred.
In further studies, ponies were given access to both cold and warm water at the same time; in those experiments, more ponies preferred cold water. Our conclusion was that if you do not give horses a choice, they will drink more warm water than they would cold. But if, for example, they have a choice between a cold stream and warm water, they might prefer to drink the cold water.
How to encourage your horse to drink water in winter
Our results suggest that if the objective is to help prevent impaction colic by encouraging consumption of water during cold weather, providing either continuously heated water, ranging from 68° to 95° F, or filling buckets with water ranging from 115° to 120° F twice daily at feeding time would be an effective strategy for most horses.
Having tank heaters in your trough to prevent water from freezing is a great idea. Topping off the troughs with hot water twice a day during feeding will likely encourage your horse to drink more water before it cools or forms ice.
Michaela Kristula, DVM, MS
New Bolton Center
University of Pennsylvania
Kennett Square, Pennsylvania
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