Vaishnava Dharmashastra 86.9

86.9

tato gavāṃ madhye susamiddham agniṃ paristīrya pauṣṇaṃ caruṃ payasā śrapayitvā pūṣā gā anvetu na iha ratir iti ca hutvā vṛṣam ayaskāras tv aṅkayet ||

Then, after having (kindled) a blazing fire among the cows (in the cow-pen) and strewed Kusa grass around it, let him boil with milk a dish sacred to Pûshan, and offer (two oblations) in the fire with the Mantras, 'May Pûshan follow our cows,' and 'Here is pleasure.' And let a blacksmith mark the bull.