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Why Do Horses Roll After Baths?

Why Do Horses Roll After Baths?

Photo: Photos.com

Q. Why do horses roll after getting baths?


A. That can be frustrating, right!? Well, I guess horses roll after getting a bath for one of the reasons they roll at any other time.

Rolling is usually put in the category of self-grooming or comfort behavior. It most certainly must have some adaptive function to have persisted for so long and among horses kept in all types of environments. We believe horses roll to scratch their backs, help shed winter coats, and to dust-bathe. 

Behaviorists theorize that dust and dirt persisting on the coat act as a sunscreen and repels insects. Horses may find a roll in the mud on a hot day has a cooling effect. My ponies will splash water out of their water tub, make mud, and roll in it; but they only do this on really warm spring days when they still have a lot of their winter hair coat. Horses will roll in larger bodies of water, like ponds, too.

Researcher Ron Keiper, PhD, observed the Assateague ponies rolling after wading through water and after rains. The loft of the horse's dry hair coat has a thermoregulating effect. So rolling may help to dry the coat, loft up the hair, and help regain this function. I'm not sure if the rate of rolling after getting wet from rain is the same as the rate of rolling after a bath. But a bath is certainly going to wet the coat right down to the skin more than will standing in a rain shower for a while. So a horse might be quite compelled to try to dry off after a bath. 

Often there's a preferred rolling spot in a pasture and that area will become a nice dust bowl. Rolling seems to be one of those behaviors that's socially facilitated, or "contagious." That is, once one member of a group starts to roll, many others follow suit. There might be a rank order preference for who goes first to last when everyone wants to roll in the preferred spot.

In other mammals and birds dust-bathing seems to also have a clear function in maintaining a healthy hair coat or feathers. In some species it's believed to also be a territorial marking behavior to disperse pheromones.  No one's really identified that function in horses, probably in part because stallions don't defend territories. But behavioristSue McDonnell, PhD, has reported stallions rolling as part of an elimination-marking sequence and harem stallions rolling near an estrus mare. Donkey jacks do roll in the presence of estrus jennies, but jacks are a little different that stallions and do maintain a territory.

We also see rolling when a horse is in pain. We see it with colic pain and in the peri-parturient mare. A normal, non-painful horse may roll after a quiet sleep episode, and he may get up and down a couple times during a rolling sequence. But once it's all done, he shakes off the dust and goes on and does other normal things. A horse with colic pain usually will have multiple episodes of rolling, doesn’t seem to shake after rolling, and in between he paces, paws, or stands (or lies down) with a depressed appearance.

About the Author

Nancy Diehl, VMD, MS

Prior to attending veterinary school, Dr. Nancy Diehl completed a master’s degree in animal science while studying stallion sexual behavior. Later, she completed a residency in large animal internal medicine at the University of Pennsylvania’s New Bolton Center and worked in equine practices in Missouri and Pennsylvania. Diehl also spent six years on faculty at Penn State, where she taught equine science and behavior courses and advised graduate students completing equine behavior research. Additionally, Diehl has co-authored scientific papers on stallion behavior, early intensive handling of foals, and feral horse contraception. Currently she is a practicing veterinarian in central Pennsylvania.

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