After a few years of raising cattle you'll have enough money to buy a Milk Processing room. It costs 60,000G, but is worth every piece of gold. The Milking room makes milking so much easier, it's automatic! You'll need to show your cows where to go by pushing them into the building a few times and from then on they will go in themselves to be milked.

Milk - Grade B - Grade A - Grade S
Normal - 75G - 115G - 150G
Marble - 115G - 175G - 225G
Brown - 115G - 175G - 225G
Star - 270G - 405G - 540G

Butter - Grade B - Grade A - Grade S
Normal - 225G - 225G - 300G
Marble - 225G - 225G - 300G
Brown - 225G - 300G - 300G
Star - 300G - 300G - 300G