It’s January. The water troughs are freezing over. The ground is frozen and the temperatures have dropped. When we think of dehydration, we usually picture a horse dripping with sweat after a long ride on a hot summer day. We rarely think of dehydration emergencies as being a winter occurrence.
Why? Because winter dehydration is a “silent” pathology.
◆︎ Winter Risk – Impaction colic:
The risk we are most concerned with in winter is impaction colic. This can be caused by inadequate water consumption. It’s
considered a “silent” pathology because there are few warning signs until it’s severe and requires veterinary attention.
Why the reduced water consumption?
➡ Dry hay: Hay is usually less than 15% moisture. Summer pasture contains 60-80% moisture. Horses can consume more than 6 gallons of water from the moisture in grass in the summer. However, on winter hay, the amount of water consumed from hay can drop to less than a gallon.
To compensate for the dry hay, the horse has to drink more water when on a hay diet than on pasture.
➡ Cold temperatures: Horses prefer cool water, but not cold water. The ideal water temperature in winter is 45° F – 65° F. Water intake drops dramatically when water is near freezing, 32° F, even if there is no ice in the trough.
◆︎ How to help safeguard against winter dehydration:
☛ Warm water. Install heated buckets or tank heaters. If that isn’t feasible, add hot water to their bucket or trough twice daily. The target is to have water available that is above 45° F.
☛ Salt. Add loose salt or electrolytes to their feed. Horses may object to their food being too salty. Another trick to increase salt consumption is to dampen the hay. Then sprinkle loose salt on the dampened hay. The dampness will cause the salt to stick to the hay.
Adding loose salt is a great idea. Many horses will not lick a cold salt block in the winter.
☛ Wet pellets or mash. By soaking pellets, the horse will consume additional water. If the horse isn’t particularly fond of wet food, brewing alfalfa tea and pouring it over the food may make it more tempting.
◆︎ Important points to remember:
● A horse will rarely consume enough snow to satisfy their water intake. The caloric expenditure to melt the snow is too high and can cause too great of a drop in body temperature.
● Monitor a horse’s water intake, if possible, to ensure that he/she is consuming enough.
● Watch for signs of dehydration. The skin pinch test may not be accurate due to a thick winter coat. Monitor other signs, such as mucous membrane color and texture, or capillary refill time.
We do the best we can for our horses. Understanding winter dehydration is a part of that.
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Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay, MSc. 2026