For production of 1 ml of milk . . . . . . . . ml of blood passes through udder.

For production of 1 ml of milk 400 - 500 ml of blood passes through udder.
To produce 1 liter of milk 500 liters of blood have to pass through the udder. When a cow produces 60 liters of milk per day, 30,000 liters of blood are circulated through the mammary gland. This represents a blood flow of 1250 liters per hour.