What should I do about my gelding that is all of a sudden acting like a stallion ? He's becoming aggressive toward the other Gelding he is pastured with to protect the mares.

Mares are probably in heat
Definitely separate him from the other geldings. Don't take a chance!
But not exactly sure what age he was gelded.
Looking through his papers, says he was a colt at age 2 and was a gelding at 5. That's all I can figure out with the paper work I have of him. He is 15 now.
When was he gelded?
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