Winter is in full force, and horse owners need to make sure their animals stay warm, according to North Dakota State University Extension Service equine specialist Carrie Hammer.
Horse owners have several ways to do that. One of them is giving the horses shelter.
“Horses have a wonderful ability to survive in the cold,” Hammer says. “A full winter hair coat is perfect for insulating the horse against the cold winter weather. However, that insulation is lost if the hair coat gets wet. Providing shelter allows the horse to stay dry on wet, snowy days and, ultimately, allows them to stay warm.”
Another way to keep horses warm is to feed them hay. Heat is produced through the digestion of feed and can be useful in helping a horse maintain body temperature in cold winter weather. The greatest amount of heat is released when microbes in the gut digest high-fibre feeds such as hay. In cattle, this process goes on in the rumen; in horses, the process occurs in the cecum and large colon.
Heat from fibre
High-fibre feeds produce more heat during digestion than low-fibre feeds. Thus, digestion of hay will result in the release of more heat than low-fibre grains, such as corn and barley. Although oats are a low-fibre grain, they will produce more heat during digestion, compared with other grains, due to their fibrous outer hull.
“Energy needs are increased during cold weather, and grains certainly can be fed to horses to help meet this need,” Hammer says. “However, the bottom line is if you want to help your horse produce body heat, feed him more hay.”
Feeding horses more also can help them stay warm. The lower critical temperature for horses with a heavy winter coat during dry, calm weather is about 30F (-1.1C). For each 10F change below the critical temperature, horses require an additional intake of about two pounds of feed per day, assuming the feed has an energy density of one mega-calorie per pound, which is typical for most hay.
A 10-to 15-mile-per-hour wind will require horses to consume an additional four to eight pounds of hay to meet their increased energy requirements when temperatures are 32F. When a horse without shelter encounters both wind and wet snow at 32F, the animal must consume an additional 10 to 14 pounds of hay.
“Considering that a 1,000-pound horse consumes 15 to 20 pounds of hay daily to maintain body weight in ideal weather conditions, consuming an additional 10 to 14 pounds becomes impossible for many horses,” Hammer says. “Therefore, in extreme conditions, hay alone is usually insufficient to supply the energy demands for a horse to maintain his body weight, and some type of additional grain source is justified.”
While many horse owners might not worry about geldings losing weight during the winter, pregnant mares should not lose weight. Many mares are in the second and third trimester of pregnancy, a time when a great deal of fetal development and growth is occurring. Research has shown that nutrient restriction during this time not only can affect fetal growth, but also can have lasting effects on the growth and performance of the foal after birth, according to Hammer.
Maintaining a thin horse takes additional feed, compared with a fleshy horse. Because a layer of fat under the skin is the second line of defence against cold weather after the hair coat, thin horses require more feed to keep their body warm. Ideally, horses should be moderately fleshy to fleshy (body condition score of six or seven) at the start of winter.
Putting a blanket on the horse also helps keep it warm. A variety of winter blankets are available.
“These can be very beneficial, especially for horses that do not have a full, healthy winter hair coat,” Hammer says. “However, blankets also can be detrimental because a blanket prevents the horse’s hairs from standing up (their natural defence against cold weather), and using too light a blanket will actually cause the horse to get chilled.”
As a general rule, horse owners should use a heavyweight blanket for subzero (below -18C) weather. These blankets usually have 400 grams or more of insulation.
Blankets also must be maintained. An ill-fitting blanket can rub, resulting in sores, and a dirty or wet blanket can lead to skin problems, such as fungal infections.
“If the predictions hold true, it sounds like we are in for a long, cold winter,” Hammer says. “Make sure to do your part to keep your horse warm and comfortable during this winter season.”