Śatapatha Brāhmaṇa ("of a hundred paths") 4.2.3.6

4.2.3.6

saiṣā kāmadughaivendrasyoddhāraḥ | tribhya evainam prātaḥsavana ukthebhyo vigṛhṇāti tribhyo mādhyandine savane tatṣaṭ kṛtvaḥ ṣaḍvā ṛtava ṛtavo vā imāntsarvānkāmānpacantyeteno haiṣā kāmadughaivendrasyoddhāraḥ

This (Ukthya graha) is the cow of plenty, Indra's special portion. At the morning feast he (the Adhvaryu) divides it for three songs of praise, and at the midday feast for three,--this makes six times, for there are six seasons, and the seasons mature all wishes here on earth: for this reason, then, this (libation) is the cow of plenty, Indra's special portion.