老牛舐犊 lǎoniú-shìdú

[an old cow licking her calf—parents doting on their children] (舐:舔;犊:小牛)。老牛爱小牛,故常以舌舔之。比喻人之疼爱其子女

愧无日磾先见之明,犹怀老牛添犊之爱。——《后汉书·杨彪传》