In my experience, that which may not concurr with best practice nor the opinion of others, depending on the weather, actual age of the calf and location, ive seen a higher mortality rate in youngsters if not shot in the Doe season and its usually more common in Roe.
For instance in Scotland (Highlands) last year whilst culling Roe Does, we left some yearling Bucks (probably about 15-20). Half were found dead by the keeper / on the next trip, you have to bare-in-mind the weather - it was cold post our first visit mid Dec (but we dont have weather fatalities usually), the terrain is 900ft + Above sea level, but most importantly despite being Dec, the calves rarely moved off from the shot site (in fact two were shot by the keeper as they just sat down in the heather and didnt move for a day or so). Having said this, we rarely start shooting Does until Dec/Jan because the followers are dependant until Dec.
Where i help cull in south, dependants are shot no questioning until late Nov/Dec as we find if left the wet/cold takes it out of them, rarely any die as a result, but they can get very thin and again are seen in the same open areas day after day looking for mum. Jan onwards depends on size, cull figures and tree damage etc.
As always it hinges on what is defined (as per my origional reply) of what is a dependant, only watching the deer, knowing the deer on your ground that you manage regular and understanding the behaviour displayed can assure you whether it is a dependant or not.
Just my thoughts
T