The synchronized silo, will automatically be kept up to date by the system. This page attempts to give some insights to this:
In the ../App_Config/Include/damforsitecore/DFS.Connect.configconfiguration file, there is a "hook", which is a timer that by default runs every minute. The purpose of this background process is to listen for changes in the DAM and then subsequently make sure that the changes are synchronized into the silo. You may change the interval between when the timer looks for changes in the DAM.
You may also stop the timer completely if you wish. This is done by commenting out the configuration entirely (practically removing it). If you choose to disable the timer, then you have to manually synchronize the DFS Silo every time a change is done in the DC to have the silo up to date.
This is how the timer (hook) looks in the configuration file: