A: Who gets paid more, Doug or Michael?

    B: They’re both good players, but Doug is our bell cow.

    Note: Literally a bell cow is the lead cow of a herd, having a bell attached to a collar around its neck so that the herd can be located easily. Cow owners often attach a ringing bell onto the neck of the head cow, hence the expression. The bell cow is the leading animal, head of the herd. Similarly, in the wild, leading wolves and lions are called the alpha male (because they are mostly male). The expression as a metaphor is mostly used in sporting circles, referring to the best players on a team.