Revākhaṇḍa of the Skandapurāṇa manuscripts (RKS) 88.30

88.30

tārayantī ca sā dattā kulānām ekaviṃśatim /
raupyakhurīṃ kāṃsyadohāṃ savatsāṃ ca payasvinīm //

And given thus, it delivers twenty-one generations of one's lineage.
[A cow] with silver hooves, a bronze milking vessel, accompanied by her calf and yielding milk,