Jack both male and female deer store minerals etc. in their skeletal frame thru out the year and their body uses them as needed to grow antlers and produce fawns etc. by the way it takes as much for a buck to produce a trophy set of antlers as it does for a doe to produce 2 fawns.
I think that you are mistaken about bucks absorbing minerals thru their velvet, but soft tissue is converted directly to bone by the deposition of minerals
(mineralization) within the matrix of cartilage and blood vessels in the developing antlers.
But if you have a link to an article, study etc. I would be very interested in reading it. Thanks, Pike