Ask the Vet: Winter Weather Care for Your Horse

Answered by, Christine Tuma, DVM, Bull Valley, Illinios
Courtesy of AAEP

Question: We live in Southern California and don’t often blanket our horses in winter. At what temperatures should we use their blankets? 45degrees or below is our current cut off and was wondering what you would recommend.

Answer: I knew I would get this one! The age-old question of “to blanket, or not to blanket,” is a question I struggle with every year as a horse owner myself!

Typically, in early fall, horse’s coats get a little thicker as they naturally begin to grow more hair as the days get shorter. There are no scientific rules about what temperature a horse should have a particular blanket, but if one decides to do so, there are several considerations to keep in mind:

  1. Remember that when temperatures drop, horses have an increased energy (calorie) requirement to stay warm. Horses ferment fiber in their large intestine, and a byproduct of this process is heat. Thus, more hay added to the diet will help keep the horse warm during cold months. This process only works for hay (NOT grain!). As a general rule, a 1% increase in energy requirement is needed to replace energy loss from cold weather for each degree the temperature falls below the horse’s critical temperature. This temperature will vary between individuals because of fat cover, hair thickness, acclimatization of the horse to cold, wetness, and wind-chill. Research has indicated that horses with a full, dry winter coat can still stay comfortable when temps are as low as 10 degrees Fahrenheit.
  2. Adaptation to cold is also an important factor to consider as horses are fairly hardy individuals that have evolved (without our help) to be able to withstand the cold. The climate typically changes gradually in most areas, so horses have time to adjust and acclimate to temperature changes (and decreasing hours of daylight) and develop an appropriate coat. If one opts not to blanket, the horse will grow its coat naturally. If blanketing, you will be committing to doing so for the remainder of the season since the horse will not have the opportunity to develop a naturally insulative coat once you start.
  3. As long as the horse isn’t shivering and its coat is dry, it is probably doing well! It is still important to monitor the horse’s well being in the cold, and to help out with some extra warmth if needed. Whether a horse is blanketed or not, it still needs some kind of shelter from the elements (stall or run-in shed). Horses in a shelter conserve up to 20% more body heat than if completely exposed to the elements, so providing adequate shelter is key.
  4. Condition of the horse: very old/very young horses have more trouble conserving/maintaining heat, so consider blanketing them first. Sick, debilitated, thin or underweight horses will have similar challenges, so consider blanketing them as well. Horses that are clipped, will obviously need a blanket in a warmer temperature than a horse with a full winter coat as well, so I would consider blanketing those individuals sooner rather than later. If your horse has any medical conditions, consult your veterinarian to further discuss their blanketing needs.
  5. As a horse owner myself, my personal criteria for blanketing (my otherwise healthy and fairly lean-ish horse and donkey) are as follows:

–<20 degrees is typically my cut off; if it drops into the ‘teens, they are likely getting a blanket. The caveat being, that if its cold in the am and expected to warm up as the day progresses, I typically will skip the blanket. And as an aside, I think my <20F cutoff is generous, meaning that research has shown that horses can tolerate much lower temps (see above) quite well when allowed to properly acclimate.

–Is precipitation in the forecast? Typically, horses can tolerate cold OR wet quite well, but if it’s going to be cold AND wet (freezing rain, heavy snowfall, ice, etc), then I choose to blanket.

–Wind and windchill: if it’s going to be an exceedingly windy day as well as cold, I will typically blanket.

–YOUR schedule: if you’ve got a long day and won’t be able to get back home to blanket or throw them some more hay (to stay warm), I would suggest blanketing on those occassions provided it’s cold enough to justify putting it on (see above).