SubscribeGift a Sub
Categories: Horsekeeping

How Horses Grow Winter Coats

This article was originally posted on October 28, 2016



Fall days—a chill in the air, geese flying south, pumpkins…and fuzzy horses. Autumn is a time when many horses are putting on their winter coats in earnest, but what causes it? Is it the change in temperature? Is it the shorter days?

Here’s a comment that you might hear around horsepeople: “Look, Roscoe is putting his coat on early—it must mean the winter is going to be extra cold!” There are a couple of reasons that this statement isn’t actually correct.

First of all, your horse’s winter coat growth response is not really caused by cold temperatures—if it were, horses wouldn’t begin to grow coats until cold weather actually hit, and then it would be too late. Instead, as horse owners know, horses actually begin to grow their winter coats as early as September, or even August in northern climates.

The real trigger for winter coat growth is diminishing light. As the fall days get shorter, the reduction of light causes the horse’s body to begin increasing the production of the hormone melatonin, which in turn prompts additional coat growth. In the spring, when daylight increases again, melatonin production drops, and the coat sheds out.

But wait—isn’t it true that horses in southern regions generally put on less of a coat than horses in a northern environment? This would tend to make it seem that temperature is playing a part, but again, it’s more about light. Southern regions (closer to the equator) are more regular in their seasonal length-of-day, and experience less of a “swing” in daylight/nighttime hours than northern regions, and thus the horses produce smaller amounts of melatonin.

Horses in the north with shorter days produce more melatonin. The result of this is that most horses naturally grow a coat that is suitable for their climate.

That said, all horses are different, and some just tend to put on heavier coats than others. And of course, winter coat thickness can vary greatly from breed to breed. One way that some horse owners try to control coat growth is to adjust artificial lighting in the barn. It’s fairly common for people to leave the stable lights on more in the spring to try to get their show horses to shed out more quickly. In theory you could also leave the barn lights off in the fall to try to get your horse to put on a coat as fast as possible.

When cold weather does strike, you’ll probably notice your horse’s coat “standing up,” and making him look fuzzier, softer, and “woolier” than normal. This is because the individual hairs in your horse’s winter coat actually spring up in cold weather, creating air pockets that provide extra insulation and therefore keep your horse’s natural body heat from escaping. This is the same way that putting on a winter jacket works for you—the jacket itself doesn’t actually provide any heat, it simply keeps your own body heat contained.

Don’t make the mistake of blanketing your horse when he really doesn’t need to be. It’s not uncommon for a well-meaning horse owner to “want to make him more comfortable” and provide a blanket. The problem that can occur is that a blanket may press down those coat hairs that were standing up, and, without this natural insulation, blanketing may actually make the horse colder. Of course there are situations when blanketing is warranted, such as clipped horses, horses that were just exercised, senior horses, or horses that don’t put on an adequate coat for the environment, etc… Blanketing should be considered on a case-by-case basis.

Has your horse started putting on his “winter woolies?”

Daniel Johnson

Daniel Johnson is a freelance writer and professional photographer, and watcher of horse movies. His favorite is probably Misty (1961). He’s the author of several books, including How to Raise Horses: Everything You Need to Know, (Voyageur Press, 2014). Dan’s barn is home to Summer, a Welsh/TB cross, Orion, a Welsh Cob, and Mati and Amos, two Welsh Mountain Ponies.

View Comments

Recent Posts

New Host Site Announced for Adequan/FEI North American Youth Championships for 2020 to 2024

U.S. Equestrian is pleased to announce that the Great Lakes Equestrian Festival (GLEF) at Flintfields Horse Park in Traverse City,…

3 hours ago

Jennifer Thompson Captures USEF Advanced Single Horse Combined Driving National Championship

Jennifer Thompson, of Lodi, Wis., and her driving horse, Funnominial CG, added the title of "national champion" to their resume…

2 days ago

2019 Certified Horsemanship Association International Conference Celebrates Award Winners; New Board of Directors Announced

Certified Horsemanship Association (CHA) members, instructors and speakers gathered in Houghton, N.Y., October 24-27, to participate in the yearly CHA…

3 days ago

At the 2019 Saddle Seat Invitational Test Event, U.S. Saddle Seat Young Riders Stars Team Wins Gold

The 2019 U.S. Saddle Seat Young Riders Stars Team secured the gold medal and gained valuable experience in international competition…

4 days ago

Video: How to Evaluate Hay Quality

Do you know how to evaluate hay quality to determine if the hay you are purchasing is really right for…

5 days ago

Allison Springer Wins USEF CCI2*-L Eventing National Championship and Francesca Spoltore Earns USEF CCI2* Junior/Young Rider Eventing National Championship Honors

As the highest-placed American in the CCI2*-LA division, Allison Springer, of Upperville, Va., and Crystal Crescent Moon took home the…

5 days ago