Skandapurana 6.3.93.6

6.3.93.6

payasā snāpayeddevaṃ trisandhyaṃ ca tryahaṃ tathā .
payo gosambhavaṃ sadyaḥ savatsā jīvaputriṇī .. 93.6 ..

One should bathe the god with milk at the three junctures of the day, and thus for three days— / fresh milk obtained from a cow that has her calf and whose offspring is alive.