Younger Does that typically conceive late will drop fawns late and these deer have a hard time catching up with the fawns that were dropped earlier in the year by more mature does. These later born fawns will usually have small spikes initially, but by the time they are 2 1/2 will likely catch up with their peers.
I believe the time to cull bucks is at the 2 to 3 mark, not 1 1/2.