Milk
From UnReal World Wiki
Milk is a drink that restores hunger in addition to thirst. Milk is very nutritious, and will often raise your nutrition after drinking even a small amount.
You get milk by applying a container to a cow or a sheep. Cows will produce between 2 and 5 lbs of milk per day, whereas sheep will often produce around 2 lbs. Cows and sheep do not produce milk during the winter. Production starts again as soon as the ground thaws in the spring.