4-6 would be mature and most healthy bucks genrally

Sargeo1 has a good source. Depending on stress in the wild anything much past 6yrs and they regress in antler growth or will not even shed them at times and just keep them until they die. On deer farms it is pretty much the same except regression starts at about 7 yrs. But they get suppliments and special diets with very little stress other then sperm donating to the tube

I'm with everyone else, 5-7 years is optimum... though after that some of the big boys start getting some real crazy character i think... which in my book is every bit as cool as size.

about 5 years