When a mare comes into season and has quite a bit of discharge and basically stands in front of a gelding so he can't do anything but notice her, does it mean that he is proud cut when he mounts her? I don't think so, but so many people tell me that if he mounts, that he has to be proud cut. Also, is there anything you can give to the mare that will help with her discharge and not being so aggressive during her cycle?

You're right about the mounting. A lot of geldings will do that if "stimulated" enough. I've witnessed quite a few geldings like that. Two had been bred before they were gelded but the others, I don't think so. It doesn't mean they weren't castrated completely. Regumate is a VERY expensive hormonal treatment you can try. I knew somebody who used it for his cutting horse that became impossible to manage when in heat. I also seem to remember reading an old-fashioned remedy, where marbles can be placed in the mare's uterus to fool her body into thinking she's already pregnant, but there are probably serious health concerns with doing that or else almost everybody who owns a mare would be doing it!

Tina is quite right - some geldings think like stallions without having any testicular tissue anywhere to be found. Regumate is one choice for helping to control estrus in mares. And the marbles actually work pretty well without any major consequences that I've heard about. It can be tricky to find the right size marble, though. Talk to your veterinarian about modifying a mare's estrus cycle. There are also some herbal supplements that might alter behavior without altering the cycle. There's one called Hormonize that some people think helps; others find no change. Can't hurt to try, though!