I guess I am going to disagree with some of what you have been told.  If you are raising freezer beef breed does make a difference.  Freezer beef if selling by the quarter or half needs to be smaller so price is affordable.  Pick a breed that will have the potential to finish before 1200 pounds.  that means preferably a Hereford, shorthorn, Angus, jersey beef cross,etc.  Stay away from the big boned breeds including dairy breeds.
Also think about your timing, when do you want the calves on pasture?  When do you want to sell the freezer beef.  Some people on here can answer when to sell better than I, but I would think they should be in the buyers freezer before Memorial Day.  Or wouldn't you figure about 5 months to grow the calves from 400 to 750#.  If so, shouldn't they be on pasture from April/May through September/October and then put on full finisher feed until you sell them.