Cows are animals, and the animal kingdom is a broad classification that includes all living things that are not plants, fungi, or bacteria.
Perhaps you are thinking of:
* The "Kingdom of the Cows" as a fictional entity: This could be a story, a game, or a fantasy setting.
* A specific geographical location: There might be a place called "The Kingdom of the Cows," but it would be an unusual name.
Can you give me more context about where you encountered this term?