Ok, maybe I should rephrase that...
My mare recently (as in yesterday) went into heat and my cousins gelding was in the pasture. He's only been gelded a few months... My mare was teasing him, and he mounted her.
He was also beating the crud out of my two year old colt and was rounding the mares up and keeping my colt away from them... he was also trying to herd the mares away from me when I was trying to catch them to feed my girl.
While I was out there, the gelding attacked my colt, and my colt ran to me to 'protect' him.
This horse has only been gelded a few months, and he's a grade Quater Horse/Racking Horse (I think)... He's got 1 foal (a filly that we own) on the ground (she wasn't planned, and we didn't own the mare at the time of the breeding).
So, how long after gelding can a recently-gelded horse still breed a mare and create a foal?