Nettie Liburt, MS, PhD, PAS
Liburt Equine Nutritional Consulting
Why should you consider special horse care practices for winter? For starters, in cold weather, your horse's energy needs increase simply to keep him warm. With freezing temperatures come frozen ground and a lack of available pasture grass. Water sources freeze, barns get closed up and exercise routines may change. This discussion contains information to help you ensure your horse stays healthy and warm throughout the winter.
Diet & Forage
The major effect of cold on an animal is an increase in energy needs. That doesn't mean you should drastically increase the amount of grain you feed your horse! For horses, forage (hay) is the best way to increase the amount of energy consumed. Horses, like humans, must maintain a constant body core temperature, and physiological changes can take place to help maintain this temperature. Cold stress occurs at temperatures below the thermoneutral zone (TNZ). The TNZ is the temperature range where heat production from metabolism does not need to be increased to maintain constant body temperature. The lowest temperature of the TNZ is called the lower critical temperature, below which metabolic heat production is increased to maintain core body temperature. The natural fiber fermentation process that occurs in the horse’s hindgut (predominantly in the cecum) produces heat, which will help maintain warmth.
More heat is produced from the fermentation of fiber in the hindgut than from the digestion of grain concentrates in the small intestine. If forage quality is poor, a ration balancer can be used to provide balanced vitamins and minerals that may be missing from the forage. For horses that have difficulty maintaining weight on forage alone, higher calorie grain concentrates or fat supplements may be added to the diet.
An increase in dietary forage demands an increase in water intake. The average adult horse needs about 10 gallons of water every day for normal body functions. Horses in heavy work and lactating mares need even more. Lack of water can inhibit all that fibrous material from moving properly through the digestive tract, increasing the risk for impaction colic. Note that snow is not an acceptable substitute for water! You may see your horse eating snow, which is fine, but he generally won’t eat enough snow to satisfy his body’s water needs.
Some horses are “picky drinkers,” but there are several strategies you can employ to increase your horse’s water intake. Keep your horse’s water source clean and ice free, even if that means simply breaking up ice that forms in buckets or troughs. A salt lick should be available free choice at all times of the year, as salt promotes thirst and drinking. If you have several horses sharing a water source, make sure that source is big enough for more than one horse to drink from at the same time. If you have a bully who “guards” the water and won't allow other horses to drink, consider adding a second source of water in a different area of the paddock.
In addition to providing ample, clean sources of water, there are other ways to help your horse increase water consumption. You can soak the grain ration and/or hay with warm (not hot) water. Offering soaked beet pulp or hay cubes can also encourage water intake. Flavoring water with something such as peppermint oil may entice a horse to drink. Electrolyte supplementation can also encourage your horse to consume water, but is not something that should be done every day.
Exercise & Clipping
Often, when temperatures drop, training and exercise activities decrease as well. If you are fortunate enough to have access to an indoor arena, maintaining an exercise regimen is considerably easier. If you are at the mercy of the elements, continuing a consistent exercise program may be more difficult. On the other hand, the winter season is sometimes used as a horse’s vacation, allowing time to recover from a busy show season or time spent otherwise working hard. Whatever your routine, keeping a horse fit in winter sometimes requires some modification to the usual routine.
Horses may sweat when being exercised in the winter. A fleece or wool cooler should be placed over the horse when exercise is finished and left in place until the coat is dry. In this way, you can help prevent the horse from getting a chill. If the horse is blanketed, ensure that the coat is dry before putting the blanket back on. Blanketing over a sweaty, wet coat can worsen a chill and put the horse at risk for hypothermia.
If exercise remains a steady part of your winter routine, clipping the horse’s coat is one way to reduce excess sweating. There are several styles of body clipping, but note that horses with clipped coats need to have supplemental protection from the elements in the form of a warm blanket.
How do you know if your horse should have a blanket? Imagine your horse with snow on his back. Normally, the snow should just be sitting there. If the snow melts and your horse’s coat is getting wet, he is losing heat and at risk for hypothermia and the chills. If the latter is the case, put a fleece or wool cooler over the horse until the coat dries, then consider putting a blanket on.
Older horses and horses that have trouble keeping weight on, or horses that have poor tolerance to cold, can benefit from the added warmth of a blanket. Blanketing will help these horses conserve energy and stay warm. Horses that are stabled and used to a warm barn will also appreciate a blanket (or heavier blanket) if heading out into bitter winds.
The first step in blanketing your horse is to determine the proper size. Using a flexible measuring tape, such as that used for sewing, measure in inches the length of your horse from the center of the chest, along the side to the point of rump, just next to where the tail lies. Ponies often measure in the 60” range, Thoroughbreds and Quarter Horses in the 70” range, and large warmbloods and drafts in the 80” range.
Blankets come in many different styles and weights. Sheets are great for early fall and late spring, and don’t contain insulation. Light and medium weight blankets (usually 100-250 grams of fill) come in handy when the weather really starts to get cold. Heavy blankets (300-400 grams) are useful in bitter cold temperatures that are well below freezing, and also for horses who have a full body clip. What you choose for a particular temperature often depends on your individual horse’s tolerance of the cold. If you find your horse is sweating underneath the blanket, you probably can use a lighter weight. Conversely, if your horse is still shivering even with a blanket, you may need a heavier, more insulated covering.
A final thought on blanketing: once you start blanketing early in the season, you need to continue to do so until the weather warms up. Constant blanketing can flatten the coat, reducing its insulating ability. While horses can adapt to the cold without a blanket, make sure that if you decide to blanket your horse you are consistent all season.
Take Home Message
Given time to adapt, horses do quite well in the cold even if they live outside. A three-sided shelter will provide basic protection from the elements, and a clean place to lie down will help a horse conserve body heat on a cold night. Stalled and blanketed horses need vigilance just as much as their outside-living counterparts. Make sure you remove blankets a few times per week to make sure they aren’t causing rubs or sores, and to ensure that your horse isn’t losing condition. Ensuring proper diet, water intake and exercise level will help your horse stay healthy all winter long!