The gopas are called Krishna's followers, who tended the cattle with Him: 'chArayan anugAn gopAn raNad-veNur arIramat' (SB 3.2.29); and Nanda is called gopa-raja, king of the cowherds (SB 3.2.32).
Gopas
गोप
Also known as वत्सप
The Gopas are the community of cowherds of Vraja, whose king is Nanda. The Bhagavata calls them Krishna's followers: as the Lord tended the cattle He went with them and delighted them with His sounding flute (SB 3.2.29). Their boys are called vatsapa, keepers of the calves, and surrounded by them Krishna grazed the calves in the groves of the Yamuna (SB 3.2.27). At SB 3.2.32 Nanda is called gopa-raja, king of the cowherds, and the Lord had him perform the go-sava sacrifice through the best of the twice-born.
Śrīmad Bhāgavata Mahāpurāṇa 3.2.27 — Sanskrit Wikisource (pinned chapter page; Devanagari from the cross-validated transcription in validation/sanskrit_skandha3.json)