31/12/2025
Cold Weather Nutrition
Brian S. Burks, DVM
Diplomate, ABVP
Board Certified in Equine Practice
Horses handle cold weather much better than hot weather; they are adapted to being out in the elements. Horses are isothermic at about 40º F, but healthy horses with a good winter coat are quite comfortable in temperatures near 0º, colder (to 40º below 0º F) if shelter is available. Shelter is needed to protect from wind, sleet, and rain. Blanketing is also useful in such conditions. Horses do need to be acclimatized to cold temperatures, meaning a gradual decrease in ambient temperature, not a sudden decrease.
Wild horses are known to gain weight in the summer months and lose weight in the winter. The extra weight helps to keep them warm during cold weather, and it is easier to gain weight during warmer weather than during cold weather. Piloerector muscles cause horses to fluff up their coat, trapping a layer of air between the skin and the outside. If there is a layer of snow upon your horse’s back, they are conserving heat and are warm; if the snow is melting, then heat is leaving the body. Shivering is also an indication that an animal is cold. Wet horses will also be cold, as they lose the ability to fluff up their hair coat.
It is important to assess your horse’s body condition at least twice weekly, meaning that the blanket needs to come off, and your hands need to go on the horse and FEEL underneath that fuzzy hair, which can make horses appear heavier than they are in fact. The ribs may be easy to palpate under the fuzz, which is not what you want- you should have to feel deep for the ribs, though they ideally are palpable. It is important to maintain the horse in a body condition score of 5 to 6 (moderate to moderately fleshy) because a layer of fat under the skin provides insulation against the cold. Horses in good body condition may not require blanketing, but those with less-than-ideal body condition often require additional methods of conserving heat. Horses in moderately fleshy condition require fewer calories for maintenance during cold weather compared to thin horses.
Winter uses more calories, and this can be especially evident in late gestation mares, the elderly, and the infirm. If you haven’t already, this is a good time to check teeth and have a good physical examination done. Horses require about 22,000 Kilo calories per day. This may increase 10-20% in the winter.
Roughage is the main heat source for the horse- not grain. Bacterial fermentation in the colon of fiber produces a lot of heat, which keeps the horse warm. The term ‘hay burner’ is used for a reason. Horses that cannot consume enough hay each day to maintain weight and warmth will require additional calories from a concentrate or vegetable oil. Concentrates are primarily digested in the small intestine and is not fermented unless spilled over into the colon, which can cause acidosis, colic, and diarrhea. Grain simply provides calories, not warmth.
Start with feeding 2-2.5% of body weight of hay each day. It is ideal to weigh this amount to ensure accuracy. Once you know this, you may be able to feed by flakes, assuming that the hay is all from the same source. For every 10-degree drop, add about two pounds of hay. Horses in the wind and rain may require even more hay. Horses kept outside should always have hay available, preferably in a feeder and not in the mud.
Senior horses may be unable to chew hay completely due to poor teeth and suffer from less efficient digestion and absorption of nutrients in the GI tract, thus requiring a feed specifically designed for them. Many senior feeds can be fed as a complete feed, containing enough fiber and fat to maintain health. Soaked alfalfa pellets or cubes can be fed several times per day to help maintain weight. Feeding 4-6 times per day provides more even levels of sugars and starch to the intestinal tract.
Also ensure that there is adequate water at tepid temperatures, between 45 and 65 degrees. Care should be taken when using tank or bucket heaters, to prevent fires due to wiring faults. Snow is not a substitute for water, as the horse cannot consume enough snow to meet its water requirement. Water is required for fermentation, but many horses will not drink freezing water, though if temperatures gradually decrease, they are more likely to drink colder water. Adequate water intake will also prevent dehydration, intestinal impaction, and colic.
Another consideration in cold weather horse care is housing or shelter. In general, even in cold climates, horses are happier and possibly healthier outdoors. Closed and heated barns are often inadequately ventilated. Horses living in poorly ventilated stables tend to develop respiratory diseases more often than horses maintained in pastures, even during cold weather.
Horses living outside should have access to adequate shelter from wind, sleet, and storms. Trees, brush, or a three-sided shed or stable can provide adequate shelter. In severe cold, horses will group together to share body heat. They may all take a brisk run to increase heat production, and then come back together to share the increased warmth. A long thick coat of hair is an excellent insulator and is the horse's first line of defense against cold temperatures. Horses that live outdoors during the winter should be allowed to grow a natural, full winter coat. Horses that live indoors and those with body clips will need adequate blankets in the cold weather to ensure that they do not get too cold. With sufficient thought and care by the horse owner, even horses that live outside in very cold climates will survive quite well during the cold winter months.
Fox Run Equine Center
www.foxrunequine.com
(724) 727-3481
