How to Get Milk from Genetic Cows
Milking Basics
Milk comes from adult cows. Hold a Bucket and use it on a cow to fill it. Depending on the cow, you may get a One Sixth Filled Milk Bucket, One Third Filled Milk Bucket, Half Filled Milk Bucket, Two Thirds Filled Milk Bucket, Five Sixths Filled Milk Bucket, or a full Milk Bottle. Partial buckets mean the cow gave less than a full bucket that time.
Combining Partial Buckets
Partial milk buckets are useful on their own, but you can also work toward a full bucket by breeding cows that give more milk. Keep the partial buckets you collect and use them where a recipe calls for milk. A Milk Bottle is the bottled form and is handy when you do not want to carry a bucket.
Breeding for Better Yield
Breed two adult cows with their breeding food and raise the baby. When it grows up, milk it and compare the fill level to its parents. Keep the cows that give fuller buckets and breed those together. Move low-yield cows out of the breeding pen. Repeat until your herd consistently gives full buckets or Milk Bottles. Feed the herd with an Unbound Hay Block placed in the pen so adults stay ready to breed.