Mare mounting other mares...anyone know why?

[gelderlander]

My 6yr mare was spotted trying to "cover" two fieldmates today. They are in season, although I don't know if the 6yr old is. She was actually grabbing hold of their necks as she mounted them, just as a stallion would. I have owned her since she was three months old, and she has never exhibited this behaviour before. Anyone know why she is doing this - the other mares are getting pretty fed up with her!

 

[Slightlyconfused]

My 22yr old who I have had for 13 years did this yesterday after my WB squirted at her.....I was on the other end of the lead rope too so I told both of them off, marched them into the yard and cold hosed off the wee on the 22yr old chest and legs and the WB tail

They were looking very sorry for themselves.....

 

[Holly Hocks]

Mine was apparently seen doing this last year as a 3 year old. Stallion like behaviour can be a sign of a granulosa theca cell tumour, so I had her scanned, and when nothing showed there, I got her blood tested to test for hormone levels - all normal. She hasn't as yet been seen doing it again. The vet isn't concerned as the tests have all been normal. She only did it to one mare - the one at the bottom of the pecking order in the field.

Mine also produces milk for no reason at all and tries to mother all new horses to the yard - she was also seen mothering one of the pet lambs on the yard - licking it as if it were her foal. Very strange but she is in excellent health so I try not to worry!

 

[SadKen]

Some display stallion behaviours when they have hermaphroditism (such as hidden testes) or elevated testosterone. I dunno why now, forgotten! but I read a paper on it which was about testosterone in racing mares and whether it gave an advantage. Fascinating stuff. You can read a PDF about it online, it's by a Marc Knobbe et al which is amusing in itself. It's called intersex in horses rather than hermaphroditism I think.

 

[HardySoul1]

I'd contact your vet if the stallion behaviour continues. Some ovarian problems cause overproduction of testosterone,hence the masculine behaviour. Knew a beautiful Arab mare who became aggressive, injection by vet eliminated the ovary problem and she became sweet and feminine again.