Harvest Moon

[Lee-yoshi]

Basically u gotta get them pregnant if they arent givin anymore milk by either using Miracle Potion or by getting them to mate with another male cow. Then itll take a while for the cow to deliver the baby cow and when thats done the mother immediately produces special milk for the baby cow. When the mothers stopped givin this kinda m,ilk then she'll start producing milk graded on how well shes been treated. Lots of special treatment like hugs and regular chats from you and good fodder for food will get you S-Rank milk. Rare but fetches good value at market! Otherwise its A or B.

Samething applies then. If they dont give milk straight away after purchase, then you gotta get 'em pregnant.

And by the way, male cows don't give milk if that's what you're trying to do!