Bhagavatapurana 3.2.29

3.2.29

sa eva go-dhanaṃ lakṣmyā niketaṃ sita-go-vṛṣam /
cārayann anugān gopān raṇad-veṇur arīramat //

29. The self-same Lord, as He grew older, tended their wealth of cattle, the source of their splendour and prosperity,

distinguished for milk-white bulls, and playing upon his flute entertained the Gopas (who always went with Him.)