I'm not sure what you guys are looking at...
He's at least 5 1/2 and most likely older. Not trying to sound too sarcastic, but they don't have big necks and shoulders when they're in velvet guys. Look at his belly, that deep brisket, and his great big ass, he's a fully mature deer--not to mention a moose. Contrary to what many people believe, most deer, even in Iowa, will not grow 170+" antlers "if you let him grow up."
Buy all of Mike Biggs' books, plus Antler Development in Cervidae, they really help.
Bronc