In many parts of the country, winter means increased stable time, decreased riding time and significantly different nutrient requirements for horses, said Louisiana State University AgCenter equine specialist Neely Walker, MS, PhD. And despite mild winters in other parts of the country, decreased temperatures and wet conditions will affect the demands on the horse’s body for heat production.

A horse’s energy requirements start to increase once the temperature drops below the animal’s critical temperature or the horse’s natural comfort zone. “Your horse’s critical temperature will depend on his current nutritional status, environmental temperatures, wind, and wet hair coats,” Walker said.

When planning the winter menu for a horse, keep in mind that the lower critical temperature for a horse is approximately 40 degrees, she said. “For every one degree lower, you should increase your horse’s feed intake by 1% of its body weight.”

For example, she said, a 1,000-pound horse should receive an additional two pounds of hay when the temperature drops 10 degrees (for example, from 40 degrees to 30 degrees).

It is less effective to feed concentrates, such as grain, to maintain a critical temperature, Walker said. Hay is a more effective way to maintain critical temperature.

“Forages contain higher fiber content than concentrates,” she said. The digestion of fiber results in a greater amount of heat being produced than the digestion of grain. Therefore, feeding hay will keep the horse’s critical temperature stable despite the environmental conditions.

During cold weather, horse owners might also notice a greater frequency of impaction colic. One of the main causes of impaction colic is dehydration.

Reduced water intake, combined with increased hay consumption, can lead to more incidence of colic, Walker said. Maintaining the temperature of water sources at 50 degrees to 65 degrees will encourage adequate drinking, which should be about 12 gallons a day.

Proper nutrition is important during winter. “It is easier to maintain body condition throughout the winter than it is to catch up if a horse is underweight,” Walker said. “Always provide good-quality forages and fresh water to maintain your horse’s health throughout the winter. Take advantage of the cooler weather and go ride.”