Sounds to me like an over anxious youngster trying to get in there before the big boys start pushin him around. I really doubt that the doe is in esterus already.
Heck my black lab does the nasty with stuffed animals, and i know for sure they aren' t in heat!
This post reminds me of an old story passed down from my grandfather about " A young bull and an old bull" .
A young bull and an old bull are standing on top of a hill in a pasture looking down at a herd of cows. The young bull looks at the old bull and says, " Lets
run down and mate with one of those cows. The old bull scoffs, looks at the young bull and says, " How bout' we
walk down and mate with them all!" .