This particular saying comes from the Jefferson County cow weighing competition, where contestants participate in teams of two. One cowboy stands at the rear of the cow, holding its tail high with his right hand and at the same time unbuckling his chaps with his left. The other member of the team has to stand in front of the cow and tries to hold it still while at the same time holding on his hat with left hand. When the cowboy at the rear is ready to make his move, the shout go�s out "Let're buck!�