Tips for healthy horses and safe facilities when temperatures plummet

Whether you love winter or would rather pass on it, freezing temperatures, bitter winds, snow, and ice all bring challenges to managing horses and the farm. With some planning ahead, these few straightforward horsekeeping tips can help keep your farm running smoothly and your horses healthy when winter weather arrives.

Thermoneutral Zones in Horses

When a horse can maintain his body temperature without expending additional energy to stay cool or warm, the ambient temperature falls within his thermoneutral zone, with the lower critical temperature marking the bottom of this spectrum. This critical temperature is a range estimated between 40 and 5 degrees Fahrenheit, explains Devan Catalano, PhD, assistant professor and equine specialist at Colorado State University, in Fort Collins.

“Horses have a thermoneutral zone—as do humans,” says Catalano. “At the upper level, horses lose weight because it’s too hot. In the winter is the flipside, in which horses need more than their baseline diet to hold their weight. This number is called the lower critical temperature; this range depends on the climate to which your horse is acclimated and the horse’s hair coat.

“So, a horse in Montana with a full winter coat will have a much lower critical temperature than a clipped horse in Florida, for example,” she adds. This lower critical temperature can play a role in horse owners’ decisions in winter, including diet and blanketing.

Equine Nutritional Considerations for Winter

Free-choice hay? Warm mash? Many horse owners turn to these standbys when frigid temperatures arrive, but what horses need depends on each situation. “Winter nutrition concerns must consider factors like critical temperature and how horses are housed,” says Kathleen Anderson, PhD, professor and extension horse specialist at the University of Nebraska, in Lincoln. “From a nutrition standpoint, for horses housed indoors, particularly in a heated barn, not much will change.

“It’s important to understand horses generate more body heat when they digest forages, as opposed to concentrates,” she continues. She recommends offering an additional pound of hay per day for every 10 degrees below the horse’s lower critical temperature and not feeding any additional grain (concentrate). “In general, at about 20 F, begin increasing hay. Be sure to provide good-quality hay; dusty hay may impact your horse’s respiratory system, leading to acute or even chronic cough.”

Here’s how Catalano figures out how much forage a horse needs. “For every degree below a horse’s lower critical temperature, there is about a 1% increase in the horse’s energy needs, which sounds like a lot but is actually about 3 pounds of hay for a 20-degree drop,” she explains. “You can estimate that if your horse’s critical temperature is about 20 F, when temperatures reach zero degrees, you should feed an extra 3 pounds of hay.

“We want to keep forage in front of our horses as much as possible, whether they are stalled or live outdoors,” she adds. “Forage is beneficial for overall hindgut health, keeping everything moving through the system and, as microbes in the hindgut digest forage, this generates heat with the hindgut acting like a furnace.”

For horse owners who like to feed a mash, she advises making it with the animal’s usual concentrate ration only: Simply take the regular amount of grain and mix it with warm water to create a soupy consistency. “What we don’t want to do is suddenly feed a bran mash to a horse whose microbiome is not accustomed to it; with the best of intentions to hydrate, you can actually cause an event like colic by feeding something unfamiliar,” she says.

While incoming winter weather calls for additional preparation and vigilance, Catalano recommends resisting the urge to modify horsekeeping routines. “A lot of people want to change or add things when a cold spell is coming in, but the best thing is to stay the course,” she says. “Consistency is key.”

Prioritize Hydration in Winter

Keeping horses drinking remains crucial year-round and, while horses might not be sweating in winter, hydration plays a critical role in overall health. Keep an eye on water consumption when temperatures drop. Some horses might be less inclined to drink, and keep in mind they consume less moisture when they’re eating hay rather than fresh pasture. Reduced water intake could increase the risk of impaction colic.

“Water requirements aren’t going to change drastically from season to season; horses need about 10 to 12 gallons of water per day,” Catalano explains. “Continue to provide salt year-round to encourage water consumption. Some research shows horses prefer water between about 45 F to 65 F so, if you can provide tepid water, your horses may find it more desirable.”

In fact, in a University of Pennsylvania study, researchers found during winter that their pony subjects consumed, on average, 40% more warmed water in heated buckets as opposed to ambient near-freezing water (TheHorse.com/13960). Heated water sources include automatic waterers, heated buckets, and tank heaters.

Check electrical water heaters often, says Catalano, noting these heating elements can shock horses when not functioning correctly.

“I often say that if your horses are looking at their water trough, you should be, too,” Anderson says.

Horse Blanketing Basics

Many horse owners choose sides on the topic of blanketing, but when and how to blanket depend on each individual scenario.

“As day length gets shorter, horses begin to grow the winter coat,” explains Anderson. “Then, as temperatures drop, thicker hair comes in.” These thicker, longer hairs help the horse retain body heat.

“Just like people wearing jackets with fill, horses have their own built-in fill: When horses get cold, their hair coat stands on end, called piloerection, which creates a buffer,” Catalano describes. “The hairs standing up trap air, warm it up, and create a barrier from cold temperatures.”

Piloerection sufficiently insulates healthy horses in good body condition (body condition score, or BCS, of 4 or above) with a normal winter coat without blanketing, provided they have access to shelter and are adapted to the climate. If any of these conditions aren’t met, blankets might be necessary, as well as in windy and wet conditions, which can disrupt the hair’s insulating buffer. Performance horses with thinner coats (due to clipping or being stalled under lights) will often require blankets.

As the temperatures dip to about 20 F, some horses need a blanket, especially older horses and those in poor body condition (BCS below 4), says Anderson. Also, be mindful of both ambient temperature and weather conditions, notes Catalano, explaining that a day with precipitation or wind affects horses more than a sunny, still day that could have a lower bulb temperature.

“For blanketing, you have to listen to the horse: If your horse has a full winter coat and is acclimated to its climate (and the weather is typical for the location), blanketing is very much horse-dependent,” she says. “If you blanket and it’s cold for your region, remember that a sheet doesn’t offer warmth as it affects piloerection by flattening the coat without insulation. I would encourage using a blanket with fill.”

Be sure to measure for optimal blanket fit: Use a soft tape measure from the center of the chest to the center of the tail to find your horse’s blanket size. Take care to fit straps correctly, check underneath blankets regularly, and remove them when wet or when temperatures warm.

Farm, Barn, and Shelters

Do horses need to come indoors in winter? Not necessarily, says Anderson. “Horses do just fine outside as long as they have shelter, are acclimated to their environment, and are fed properly.” 

“For horses that live outdoors, adequate shelter from wind and precipitation is critical,” notes Catalano, and some states have minimum requirements for livestock shelter. Horse owners commonly use run-in sheds, and evergreen shelterbelts (windbreaks) provide additional protection.

Ensure pasture-kept horses live in appropriate groups so a dominant horse doesn’t prevent other horses from utilizing shed spaces and accessing forage and water, notes Anderson.

While winter conditions can be challenging, Anderson and Catalano say targeted strategies can help facilities function smoothly.

When days are still warm:

• Be sure water lines lie below the frost line and insulate exposed pipes.
• Consider building a small structure around each hydrant to help insulate it.
• Check that roofs meet code requirements for snow loads.
• Address grading and drainage around the barn, gates in turnout areas, and walkways to prevent ice buildup in areas where water accumulates.
• Have a plan to provide ventilation to minimize horse and human exposure to dust and ammonia within stables.

Once cold weather has arrived, be sure to:

• Remove hoses to minimize the risk of hydrants freezing.
• Drain hoses and bring them into warm areas when temperatures are consistently below freezing.
• Think strategically before snow falls: Have snow removal equipment fueled and easily accessible and leave gates open to empty paddocks so you can plow walkways into turnout areas.
• Apply sand, stone dust, or manure to icy or snowy surfaces for traction, but avoid shavings, which can become slippery. Use salt only in areas for human—not equine—traffic.
• Consider keeping horses barefoot, if possible, to minimize snow buildup in hooves. For shod horses, discuss with your farrier if snow pads and snow rims would be appropriate.

Take-Home Message

With some preparation, extra vigilance, and minimal changes, your farm and horses can comfortably handle the winter—no matter the weather.

This article is from the Winter 2024 issue of The Horse: Your Guide to Equine Health Care. We at The Horse work to provide you with the latest and most reliable news and information on equine health, care, management, and welfare through our magazine and TheHorse.com. Your subscription helps The Horse continue to offer this vital resource to horse owners of all breeds, disciplines, and experience levels. To access current issues included in your subscription, please sign in to the Apple or Google apps OR click here for the desktop version.