Winter and Cold Weather Care (Book Excerpt)

Editor's Note: This is an excerpt from Care and Management by Heather Smith Thomas. This book is available from

Winter care may be easy if your climate is mild or more involved if you must deal with sub-zero temperatures or wet freezing rain. Complexity of your winter horse chores also will depend on whether your horse is indoors or outside. Even if your horse is on vacation, some aspects of caring for him become more important during cold weather.

During winter the horse needs additional forage to create more body heat, clean unfrozen water, and some kind of shelter or windbreak. In some climates he may need blanketing if his winter hair coat is inadequate. Cold weather is not a problem if he's had a chance to grow a good winter coat; it's the wind and wet weather that can chill him.

Horses handle cold weather much better than humans do. Their natural comfort zone (energy-neutral, in which they don't need to expend extra energy to maintain normal body temperature) is from about fifteen to sixty degrees Fahrenheit if weather is not wet or windy. The horse's body is better adapted for creating and conserving heat than dissipating it.

Coping With Cold

As fall weather changes to winter, the horse's body undergoes a series of physiological changes, some of which began long before the first frosts. As soon as the days begin to shorten in midsummer, the horse begins to grow a new coat, denser than his summer hair. When brushed in late summer he'll shed some of his short summer hair. His metabolism begins to change, enabling him to store more fat for insulation and energy reserves. A layer of fat under the skin makes it more difficult for heat to escape from the body and protects against cold weather.

As soon as nights start getting cold, his body begins to change, even if days are still quite warm. He grows thicker hair as protection against winter cold, but if he is blanketed to prevent this extra hair growth or clipped, he won't do well outside during winter storms. Clipping makes it easier to cool out and groom a horse being ridden in winter, but don't clip a horse that must spend time outdoors. If he does have a good winter coat, don't blanket him or bring him into the barn just because of bad weather. Horses prefer being outdoors even in the coldest weather and do fine if they have some kind of windbreak or a run-in shed to get out of driving snow or rain. A horse in good condition with a good hair coat is usually better off outdoors.

 Long hair traps a layer of warm body heat between skin and cold air. Tiny muscles in the skin make the hair stand erect for more insulation. Blood vessels near the skin constrict, conserving body heat by keeping the blood closer to the warm interior of the body, not allowing heat to escape from the body surface.

A normal winter hair coat is more insulating than most horse blankets. A blanket can make the horse colder because it flattens his hair coat, destroying its insulating effect. Blanketing may be necessary however, for a clipped horse, one moved north during winter without a chance to grow a heavy coat, or a horse that must stand outside in a storm without a windbreak. If a horse becomes so wet and cold he must shiver to maintain body temperature, he'll burn more calories and need extra feed or he'll lose weight. Under those conditions, he'd be better off indoors or blanketed.

A well-fed horse can manage fine at temperatures down to thirty or forty below zero Fahrenheit if there's no wind to ruffle the hair and destroy its insulating quality. The downward direction in which the hair grows -- along with the oil glands that waterproof the hair and make it a bit greasy -- help keep a horse dry. The hair coat's density makes such a good overcoat that snow can form ice on the coat's outer surface without the skin becoming chilled.

A lot of moisture is needed to soak through to the skin since most of the water runs off, but once a horse does get wet, he can become chilled. A wet horse loses body heat up to twenty times faster than a dry horse because moisture flattens out the hair and eliminates the air spaces between them. Even a warm winter storm (such as rain instead of snow) can be hard on a horse if he gets soaked and then is chilled by dropping temperatures before he has a chance to dry off. If a horse gets muddy, groom him to keep the coat from becoming matted down.

Make sure horses have adequate flesh. Horses should not be too fat but need enough for an insulating layer. Most wild animals go into winter fatter than they are at other times of year; this is nature's way to protect them against the cold and to give them some reserves for energy and body heat. A layer of fat under the skin needs little energy to maintain and has few blood vessels to lose heat. Humans may frostbite toes and nose in cold weather, but horses rarely do. A horse's blunt muzzle is so richly supplied with blood that it can withstand extreme cold without freezing. Long nasal passages with bone spirals and air pouches help warm the cold air before it gets to a horse's lungs. Feet and legs withstand extreme cold and standing in snow without discomfort or damage. A horse's legs are just bone and tendons below the knees and hocks, requiring less circulation than muscles, making them less vulnerable to frostbite. The cells in bones and tendons need less blood for maintenance and also lose less heat. The horse is able to shunt most of the blood away from his feet and still have a functional foot. When the feet start to get cold, shunts open up so that the blood flows from the smallest arteries directly into the veins without having to pass through the smaller capillaries.

 If he gets cold, he starts to shiver, his muscles rapidly contracting and relaxing, which quickly raises his metabolism and rate of fuel burning in the muscles. With large blocks of muscle, the horse can shiver more readily and more comfortably than a human. Most of this muscle action converts to heat, making this is a very effective way to warm himself. It takes a great deal of energy, however, to shiver for a prolonged period.

About the Author

Heather Smith Thomas

Heather Smith Thomas ranches with her husband near Salmon, Idaho, raising cattle and a few horses. She has a B.A. in English and history from University of Puget Sound (1966). She has raised and trained horses for 50 years, and has been writing freelance articles and books nearly that long, publishing 20 books and more than 9,000 articles for horse and livestock publications. Some of her books include Understanding Equine Hoof Care, The Horse Conformation Handbook, Care and Management of Horses, Storey's Guide to Raising Horses and Storey's Guide to Training Horses. Besides having her own blog,, she writes a biweekly blog at that comes out on Tuesdays.

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