Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.3.6

2.6.3.6

atha vāyavyam payo bhavati | payo ha vai prajā jātā abhisaṃjānate vijigyānam mā prajāḥ śriyai yaśase 'nnādyāyābhisaṃjānāntā iti tasmātpayo bhavati

After that there is an (oblation of) milk to Vâyu. Now it is to milk that living beings readily take, when they are born: 'May the creatures readily take to me--now that I have gained the victory (by means of the Sâkamedha offerings)--for my prosperity, glory, and support!' so he thinks, and hence that (oblation of) milk.