To all these the king narrated his dreams, but none could interpret them to his satisfaction. Some said that the seven fat kine were the seven legitimate kings that would rule over Egypt, and the seven lean kine betokened seven princes that would rise up against these seven kings and exterminate them. The seven good ears of corn were the seven superior princes of Egypt that would engage in a war for their overlord, and would be defeated by as many insignificant princes, who were betokened by the seven blasted ears.
Pharaoh's Vision of Egypt
Legends of the Jews 1:155