I have always heard that the pituitary gland influences
the sensitivity to testosterone or the amount, I don't remember which.
Anyway, I have one gelding who was gelded at 13
months. He is a real "hearts and flowers Romeo" who has been known to
bring mares into heat (could have had a career as a teaser horse). I have
another, who was a crytorchid, but was operated on and I saw the vet remove both
testicles (one was in the inguinal (?) canal). He has not had the same
access to mares as my first gelding, but to this day "talks" like a stallion and
does that "huh, huh, huh" when you touch his chest. The last horse was
also gelded I'm not sure at what age. He is a little afraid of mares
(won't get close enough to be ponied, for example) and only "talks" to his
pasture mates when he is afraid they are leaving him alone.
I would not have a mare out with them because it would
engender discontent among the geldings no matter what the mare did. That
being said, when I was boarding the older Romeo in a mixed herd of 20 or so, my
boy cut himself out a mare to love and a gelding buddy and these three hung out
apart from the rest of the herd.
