People combat cold weather by putting on additional clothing, but horses fight the elements by using more energy to maintain body temperature. While most people can address their own needs, horses are dependent upon their owners to provide proper nutrition and protection from the weather, said Dave Freeman, PhD, PAS, Dipl. ACAN, Oklahoma State University Cooperative Extension equine specialist.

Energy for Body Warmth

"The temperature below which a particular horse starts to expend additional energy for maintaining body warmth (called the critical temperature) will vary," he said. He attributes this to several factors including the amount of fat each horse has, the thickness of their winter coats, how well the horse acclimatizes to the cold weather.

For example, a horse with short hair, exposed to wet, cold weather, might need significantly more energy when the temperature gets below 50° F (10° C). A horse acclimatized to cold weather, with a thick hair coat and fat cover, may not expend appreciably more energy until the temperature drops below 30° F (-1° C)