have you made your cows pregent i had the same proplem

dont buy a boy cow cause they wont get the girl prengent and chanes of geting a boy is 1
to 2

Use the miracle potion to impregnate your cow. once she is done producing mother's milk,
she will start producing regular milk.

ummm lets see... theirs ice cream!!! you make that with star milk and brown milk. its sooo
cool!!! you can only make it on dessert mode though. hope i helped!!