Parmigiano Reggiano is produced exclusively in the provinces of Parma, Reggio Emilia, Modena, Bologna to the left of the Reno river, and Mantua to the right of the Po river: this is the area hosting the farms where the cattle are fed on locally grown forage. The feeding of cattle complies with the norms of a strict specification that bans the use of silage, fermented feeds and animal flour.