Most colts make even better geldings. So even though Cowboy might not be too happy, it's the best thing.
Just remember, the best riding and all around horses are geldings. Reliable and calm and quiet. He's doesn't need that extra bagage in life. He will be just fine and happy as a gelding and mom won't lose any flesh over it. I only wish my horse when I got him 16 years ago was all ready a gelding. As I walked him off the trailer after purchasing him, he grabbed my upper arm and wouldn't let go. When I got him to the barn and in his stall, the next thing I did was call the vet and make that serious appointment in life. He's still a mouthy thing at 17 years of age. Because the people before me, let him get away with it and I couldn't stop him. Not till this day. You made the right decission.
That is so funny! We had a quarter horse stud colt that we wanted to keep a stud for a while longer for him to develope the "masculine" look, however, it soon became apparent that this idea needed to be nicked in the bud when our little "man" started mounting anything and everything in sight. Not such a good idea so he because our beloved gelding.
When we gelded our Pinto colt, he really calmed down, and is actually paying attention. "Good stallions make Great geldings!"