One of our mares rubs her butt on everything, all the time. It messes up the top of her tail, and she always has these big scratch marks across her butt.

We can’t seem to get her to stop it. We have dewormed her regularly and tried all sorts of different wormers. It seems like more of a nervous habit. Could she be rubbing herself like a stallion masturbating? Is that normal? Why is she doing it so much? We see her doing it almost every day. We don’t see other mares doing that or having the scratch marks and broken tail hairs.       via e-mail

Rubbing like you describe is usually due to some irritation in the perineal area. Over the years we’ve seen it in mares with vaginitis, a foreign object in the vagina, urinary tract problems, dermatological (skin) conditions, and cystitis (inflammation of the urinary bladder). Have your veterinarian check out everything behind that might be provoking the rubbing.

Mares do not normally rub their clitoris in a self-stimulating manner analogous to the spontaneous erection and penile movements in stallions. It would also be a good idea to have your vet check to be sure her genitalia is normal for a mare. I once saw a mare that was an inter-sex with an enlarged clitoris that was similar to a small penis. She experienced periodic erections of that structure and rubbed her butt as if it was itchy. It’s a rare condition, but it should not be ruled out without a veterinary exam