Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 18
अथाह सुरभि: कृष्णमभिवन्द्यमनस्विनी । स्वसन्तानैरुपामन्त्र्य गोपरूपिणमीश्वरम् ॥ १८ ॥
athāha surabhiḥ kṛṣṇamabhivandya manasvinīsva-santānair upāmantryagopa-rūpiṇam īśvaram
Mother Surabhi, along with her progeny, the cows, then offered her obeisances to Lord Kṛṣṇa. Respectfully requesting His attention, the gentle lady addressed the Supreme Personality of Godhead, who was present before her as a cowherd boy.
The statement here that the heavenly cow Surabhi approached Lord Kṛṣṇa along with her progeny (sva-santānaiḥ) is a reference to the transcendental cows who play with Lord Kṛṣṇa in Vṛndāvana. Although Lord Kṛṣṇa’s cows are transcendental, the heavenly cow Surabhi affectionately saw them, as indeed Lord Kṛṣṇa Himself did, as related to her. Since Lord Kṛṣṇa was appearing in the form of a cowherd boy, the whole situation was quite congenial, and Surabhi took the opportunity to offer the following prayers.