Yang Biao's son Yang Xiu was killed by Cao Cao because of his arrogance and political stance. Once, when Cao Cao saw Yang Biao, he asked, "Why are you so thin?" Yang Biao replied, "I'm ashamed that I don't have the foresight of Jin Ridi. When I am old, I still feel like an old calf. " Cao Cao changed his face and apologized to him. Later, people used the term "old calf" to mean that parents love their children.