Among these sons, Pṛṣadhra, following the order of his spiritual master, was engaged as a protector of cows. He would stand all night with a sword to give the cows protection.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
पृषध्रस्तु मनोः पुत्रो गोपालो गुरुणा कृतः । पालयामास गा यत्तो रात्र्यां वीरासनव्रतः
pṛṣadhrastu manoḥ putro gopālo guruṇā kṛtaḥ | pālayāmāsa gā yatto rātryāṃ vīrāsanavrataḥ
SB 9.2.3