Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.4.22

2.4.4.22

atha vājibhyo vājinaṃ juhoti | ṛtavo vai vājino reto vājinaṃ tadvanuṣṭhyevaitadretaḥ sicyate tadṛtavo retaḥ siktamimāḥ prajāḥ prajanayanti tasmādvājibhyo vājinaṃ juhoti

He then offers the whey to the (divine) Coursers. Now the Coursers are the seasons, and the whey is seed: and thus the seed is cast properly, and the seasons bring forth the seed so cast in the form of these creatures. This is why he offers the whey to the Coursers.