When turned out on a brisk winter day, does your horse race around the paddock, bucking and kicking up her heels? Or after a spell of rainy weather, is she spirited on the trails and hard to stop? People often declare: “My horse is frisky because it’s cold out!” But how is a horse’s behavior really affected by the weather?

How Horses Stay Warm

When it’s cold, wet, and windy, conserving body heat can be a matter of life and death. Ancestral wild horses adapted to climates with frigid winters and limited food. Some domestic breeds are better suited for cold and wet conditions than others, but most healthy horses can maintain their normal body temperature of about 100°F over a broad range of outside temperatures. When the thermostat dips below 5-10°F—the lower limit of their “thermo-neutral zone”—horses need to adopt various strategies to prevent dangerous loss of body heat.

Lively running, bucking, and other fresh behavior burns calories and isn’t a strategy horses use to stay warm when it’s cold out. Instead, they conserve energy, huddle together, and seek shelter.1, 2 During the summer horses tend to use shelters to protect against biting insects. During winter, they’re more likely to use them to prevent body heat loss when it’s rainy. But they don’t tend to use shelters  for warmth when it’s cold and dry.2 Smaller horses and ponies are better suited for cold weather because they have less surface area that’s exposed to the elements. A dense winter coat and body fat also provide insulation from the cold; clipping and blanketing keep the horse’s hair short and clean but might interfere with the coat’s natural insulating properties.

Findings from several research studies suggest horses are actually less active when the weather is cold and wet. For example, compared to other times of the year, during harsh cold and rainy Norway winters, Icelandic horses spend less time running and playing but the same amount of time eating, walking, and sleeping.3 Wild Przewalski horses4 and Shetland ponies5 are also less active in winter. Interestingly, they are able to conserve energy by slowing the body’s metabolic processes—a condition called winter hypometabolism—which could be an adaptation to conditions of food shortage and harsh weather. With regular access to food and shelter during winter, most domestic horses have no difficulty maintaining normal body temperature even in locations where the thermostat regularly plunges to frigid levels.

Exercise and Socialization

Horses are often stabled more and exercised less during cold, wet winter months, and in many areas, show season peaks in the summer. Rather than serving as a restful break, winter time-off can create a significant change in routine, with a steep drop in physical activity, mental challenge, human attention, and socialization with other horses. Day-length is also shorter in winter, which could mean more time confined to a stall and less time for turn-out, training, and riding. This relatively impoverished winter lifestyle probably explains why some horses are fresh and more spirited at this time of year.

Your “fresh” horse might be entertaining to watch and lively under saddle, but this burst of energy during cold and rainy weather could be a warning sign that she’s not getting enough activity, in general. A winter routine should include daily opportunities for exercise and turnout. If all-day turnout isn’t possible, a few hours a day in an arena or pasture can help, especially if it includes time with other horses.

When winter conditions limit or prevent training, substitute that time with more environmental and social enrichment. Spending “quality time” with your horse will help strengthen the human-horse relationship and could include trick training, which is fun and mentally engaging. Some horses will play alone with safe, rugged toys, especially if the toy also dispenses treats. A slow feeder is a healthy enrichment item that will give your horse something to do for hours; she will spend more time grazing and less time standing, which more closely resembles the natural activity of free-ranging horses.

References:

1Heleski, CR, and Murtazashvili, I. (2010) Daytime shelter-seeking behavior in domestic horses. Journal of Veterinary Behavior 5; 276-282

2Mejdell, CM and Bøe, KE. (2005) Responses to climatic variables of horses housed outdoors under Nordic winter conditions. Canadian Journal of Animal Science 85; 301-308.

3Jørgensen, GHM, AANensen, L, Mejdell, CM, and Bøe, KE. (2015). Preference for shelter and additional heat in horses exposed to Nordic winter conditions. Equine Veterinary Journal 48; 720-726.

4Arnold, W, Ruf, T, and Kuntz, R. (2006). Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure. Journal of Experimental Biology 209; 4566-4573.

5Brinkmann, L, Gerken, M., and Riek, A. (2011). Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus). Journal of Experimental Biology 215; 1061-1066.