NLDB (National Livestock Development Board) has two parlors selling milk related products.
The first sits just opposite the National Livestock Development Board head office, situated just 100 meters away from the Narahenpita Junction, along the Nawala road. They serve fresh milk here, either chilled or un-chilled. A liter of fresh milk is 125 rupees (10 rupees cheaper if you bring your own bottle) but I had a cup of 250 ml milk here (chilled) for 40 rupees. There are 180 ml plastic packets for 30 rupees if you want to take it away. They also sell curd: a pot of 1 liter curd (kiri hattiya) costs 180 rupees.
The place is clean, tidy and there is sufficient space inside. There is a model cow as well that kids love to play on and the service is fast.
You have to call +94112501701 and they will transfer the call to the counter if you need any information or place a bigger order.