It sure seems to me that when stallions are present, my 19 year old Hannoverian mare’s cycles become transparent, but when there are no stallions, she exhibits strong heat related behaviors and emotionality and can be difficult to manage. Am I just imagining this correlation? SN – 12/30/11

You’re not necessarily imagining a problem, but the signs that you describe are also not a giveaway for any particular problem.  One thing that I’d think about in a 19 year old mare with signs that you describe is Equine Cushing’s Syndrome – you can read about it by CLICKING HERE.   Older mares can exhibit some weird behaviors due to Cushing’s.   An ovarian problem is a less likely possibility, as are other problems of the reproductive tract.  Either way, it’s certainly worth having your veterinarian take a look.