My experience when hunting in areas with a mature buck population, only the older mature bucks will grunt while chasing a doe. The young bucks do not want the attention from older bucks.
Interesting observation. I have to admit, I almost never hear yearling bucks grunt, even when they're chasing a doe.
Makes sense to me. I typically hear grunting every year, but it's minimal. This year, I heard more grunting than I probably ever have. Which would make sense to this theory, because we were for sure lacking mature deer.
I've noticed yearlings & 2yr olds are the most prolific grunters, but only older bucks growl or snort-wheeze. I've also not noticed younger bucks suppressing their vocalizing due to the presence of older bucks. It's been my experience that deer (bucks AND does) vocalizations mirror the habitat. In wide open areas where deer can see & identify other deer from distance, I rarely hear a grunt even during chases. Contrast that with extremely thick stuff that seems like a maze of tunnels and that's where I see and hear the most intense rut action such as grunting, chasing, and rubs.
I've always suspected that when deer are close enough to hear & smell one another but can't easily see one another, they vocalize for pinpoint location purposes, such as "here I am!!!". I think it's also why I see so many more rubs in thick areas than open areas. In the open you can see a rub from way off. But in a thicket you can't see as far, so more of them increase the odds they'll be seen.
I could be completely wrong about it though. I've always noticed the link between vegetation thickness and visible/audible rutting activity and rationalized it best I could. Ironically, one of the properties I'm currently hunting is the best, most exciting rut activity I've ever seen anywhere, and it also happens to be the place with all the half rack, broken, deformed antler bucks. Spikes and forkies in there grunt their heads off, so perhaps that's why they're getting all beat up!