Shatapatha Brahmana 5.5.2.8

5.5.2.8

atha śyenīṃ vicitragarbhāmadityā ālabhate | tasyā eṣaivāvṛdyāṣṭāpadyai vaśāyā iyaṃ vā aditirasyā evainametadgarbhaṃ karoti tasyā etādṛśyeva śyenī vicitragarbhā dakṣiṇā

Thereupon they seize a reddish-white (cow) which is clearly with calf, (as a victim) for Aditi. The mode of procedure regarding her is the same as that of the eight-footed barren cow. Now, Aditi being this earth, it is her embryo (child) he thereby causes him (the king) to be. The sacrificial fee for this (cow-offering) is just such a reddish-white cow that is clearly with calf.