We suggest that you follow the recipe if it calls for pre-browning then go ahead and brown it up. While this is an added step it is usually included to create a more flavorful product and to get rid of excess fat that may alter the flavor of the end result of the the dish. With recipes that call for ground beef, turkey, chicken or pork (with the exception of some recipes such as meatloaf an meatballs) you will want to cook the meat on the stove-top fully before adding it to the slow cooker.