Śatapatha Brāhmaṇa ("of a hundred paths") 9.2.3.38

9.2.3.38

tāṃ saviturvareṇyasya | citrāmāhaṃ vṛṇe sumatiṃ viśvajanyāṃ yāmasya kaṇvo aduhatprapīnāṃ sahasradhārām payasā mahīṃ gāmiti kaṇvo haināṃ dadarśa sā hāsmai sahasradhārā sarvānkāmānduduhe tathaivaitadyajamānāya sahasradhārā sarvānkāmānduhe

[He puts it on, with, Vâg. S. XVII, 74], 'I desire the manifest favour of the admirable Savitri, enjoyed by all men; that great cow of his, the thousand-streamed, teeming with milk, which Kanva was wont to milk;'--for Kanva indeed saw her, and she, the thousand-streamed, milked him all his wishes (objects of desire); and in like manner does the thousand-streamed one now milk to the Sacrificer all his objects of desire.