This is from an article on the QDM website.

The Holzenbein study monitored 34 buck fawns divided into two groups - 19 that were left with their mothers (non-orphans) and 15 whose mothers were harvested or removed (orphans). The results were surprising. By 30 months of

age, 87 percent of the non-orphans had dispersed from their birth areas, but only nine percent of the orphans had left theirs. In addition, the non-orphans died at more than twice the rate of the orphans.

They reasoned that dispersing bucks were less aware of their new surroundings and more likely to succumb to harvest by hunters as well as death from predation, accidents and other mortality factors.