The idiom “An old cow dotes on her calf” (lǎo niú shì dú) is used to describe parents’ love of their children.
The idiom is based on a story about Yang Biao from the Book of the Later Han, which is an official Chinese historical text covering the Han Dynasty from A.D. 6–189.
As the story goes, Yang Xiu, son of Yang Biao, was the secretary of Cao Cao. Yang Xiu was very talented and intelligent. Often times, it was as if he could read Cao Cao’s mind.
Cao Cao was a very suspicious person. He believed Yang’s talent and capabilities might threaten his future. So, he found an excuse to have Yang Xiu executed.
Hearing that Cao Cao had taken Yang Xiu’s life, Yang Biao, was quite grieved. He dared not complain to Cao Cao. However, he shed tears secretly at home.
One day, Cao Cao met Yang Biao and asked: “What has happened? You look so pale and thin!”
“I feel ashamed of myself,” Yang Biao replied. “Remember, Minister Jin could kill his two sons for their misbehavior so that they could not cause trouble in the future.”
“However, I am not as smart as Minister Jin. I am still quite attached to the deep feeling I have for my son, just like an old cow that licks her calf. Therefore, pining, I am so pale and thin.”
Yang Biao’s words made Cao Cao feel quite guilty.
Later on, the expression “An old cow dotes on her calf” became an idiom to describe deep parental love.
Note: Cao Cao (A.D. 155–220) is known as one of the main figures of the Three Kingdoms period (A.D. 220–280 AD). He was the ruler of the State of Wei and, though considered a military genius for the period, has been portrayed as a cruel tyrant.