Mahabharata 13.77.6

गावो भूतं भविष्यच्च गावः पुष्टिः सनातनीगावो लक्ष्म्यास्तथा मूलं गोषु दत्तं न नश्यतिअन्नं हि सततं गावो देवानां परमं हविः

gāvo bhūtaṃ bhaviṣyacca gāvaḥ puṣṭiḥ sanātanīgāvo lakṣmyāstathā mūlaṃ goṣu dattaṃ na naśyatiannaṃ hi satataṃ gāvo devānāṃ paramaṃ haviḥ

Our plain-language meaning of this verse is waiting for scholar review.