Every winter, horse people produce copious amounts of literature on whether or not you should blanket your horse. I have friends who insist you should never blanket a horse and others who insist all horses should be blanketed under certain temps. The reality is much more complicated. Like everything in the horse world, it depends on your horse and the situation.
Horses are built to survive in the cold, but the reality of living with horses is that our very relationship with them is unnatural. We create unnatural situations but helping to keep horses healthy that would have been weeded out by natural selection in the wild. We create unnatural situations by clipping our horses or using lights to keep their coats slick, so they can be show-ready as late as November or as early as February. It’s only fair that we respond by making sure we keep them warm!
My gelding is an excellent example of this. He has terrible teeth. He’s 11 and has had three teeth pulled so far. If he were in the wild, he would have starved to death two years ago. Instead, my vet keeps up his teeth, and I keep him blanketed in freezing temperatures, since he can’t consume enough hay to keep himself warm. My mare on the other hand almost never gets a blanket. I just shovel the hay in her direction, and she does just fine.
I’ve included the full size image below of the the poster Auburn Agriculture offers. I highly recommend following the link and paying the $15 for a full-size laminated poster for your barn. For me, it helps my non-equestrian husband figure out whether or not he should blanket the horses when he’s responsible for bringing them in. For larger barns, this poster can guide less experienced horsemen/women in figuring it out.
I highly recommend reading To Blanket or Not To Blanket from Colorado State University’s vet school, which gives a great overview of basics. Equus Magazine Blanketing Q & A provides some great basics as well. Perhaps the best article online I’ve found is Thermoregulation in horses in a cold time of year. It’s lengthy but gives the reader an in-depth look at the science behind whether or not to blanket. Natalija Aleksandrova includes her sources if you want to dig a little deeper.