If I remember correctly, UCDFD switched from being dispatched by the City of Davis to Yolo Emergency Communications Agency (YECA) in the summer of 2018. I don't know the exact reason, but I'm guessing the cost of dispatching had something to do with it.
Being dispatched by YECA, the UCDFD tone-outs go out on GOLD, but all other unit-dispatcher communications go over the UC Davis 800 MHz radio system (until UCDFD switches over to SRRCS this summer).
UCDFD still has daily automatic-aid calls into the DFD jurisdiction daily. They switch over to the City of Davis 800 MHz radio system during these runs (again, also, until the City of Davis switches over to SRRCS this summer).
I could see City of Davis FD switching to YECA for dispatch services at some point. They are the last holdouts. Davis PD will likely stay with their own dispatching.