Horses with a summer hair coat are less cold-tolerant than those with a fully grown winter haircoat. In Saskatchewan, winter haircoats typically begin to grow in September in response to the shorter days and cooler temperatures.
Temperature Tolerance
Mature horses that are in good body condition with good hair coats are quite cold-tolerant. Young and thin horses are less cold-tolerant. Donkeys are not cold-tolerant and need to be given special consideration during winter.
Feeding in the Winter
The easiest method of feeding horses in winter is to feed them high-quality, free-choice forages. Most horses will eat approximately two per cent of their body weight in hay per day. Average daily free-choice intake of hay by a 600 kilogram (1,320 pound) horse is 12 to 15 kilograms (26 to 33 pounds) per day or about half of a 65-pound square bale per horse per day.
If you are limit-feeding horses outdoors, adult horses being fed at maintenance require an additional two pounds more feed per day for every 5 C drop below the lower critical temperature of -15 C. At - 40 C, a mature horse will need 4.5 to five kilograms (10 to 12 pounds) more than it ate at temperatures above -15 C.
Good-quality hays have a high leaf-to-stem ratio (i.e. more leaf than stems). Feed your horse palatable hays. Mouldy, weed-ridden, coarse-stemmed hays do not taste good to horses and can hurt their mouths (e.g. prairie wool awns or thistles). You can expect that they will not be eaten in sufficient amounts.
Use good-quality, highly-digestible hays and supply a sufficient quantity. Coarse, over-mature hays are low in energy and high in indigestible fibre. In cold weather, when energy demands are high, over-mature hays will not supply sufficient energy and, if fed without sufficient water, can predispose the animal to digestive tract impactions. Alternatively, some grain can be added to the diet. Caution must be used when adding grain to the diets of horses unaccustomed to grain, because laminitis or colic may occur. All horses fed grain should be gradually adapted to small amounts of grain over a period of five to seven days, depending on the total amount of grain they are fed.
Fermentation of hay occurs in the hind gut and actually warms the horse from the inside out. Grains do not do this. Therefore, hay is very important in your winter feeding program.
Supplements
Supplemental vitamins A, D and E may be needed. Appropriate mineral-vitamin mixes should be chosen. A fortified two-to-one ratio of calcium-to-phosphorus (Ca-P) mixture is recommended for feeding with grass hays; a one to one Ca-P mixture is recommended for feeding with alfalfa hay. A fortified vitamin-mineral mixture combines major minerals (calcium and phosphorus), trace minerals (copper, zinc, etc) and vitamins (A, D and E). The ratio in a supplement and the absolute amount of mineral are important. Typically, look for a product with at least 10 per cent to 20 per cent calcium and eight to 10 per cent phosphorus.
Water
Water helps maintain appetite and digestive function. Provide adequate heated water (between 2 C and 10 C) if possible. Horses must drink to eat and must eat to drink. Snow is not a suitable substitute for water.
Shelter
If available, a well-bedded, south- or east-facing shed is useful, particularly for young and old horses, but is beneficial for all horses, especially "thin-skinned" horses. Alternatively, provide protection from the wind by providing bedding areas behind snow fences, in coulees or bluffs or among trees. Horses that can lie down on bedding will conserve body heat. Horses that lie down on snow lose body heat.
The Code of Practice for the Care and Handling of Equines are nationally developed guidelines and include information on housing, care, transportation and other animal husbandry practices.