Ounces of breastmilk

How many ounces of breastmilk are you giving your baby? I've always exclusively breastfed (no bottle) because my son was not having any type of fake nipple in his mouth, never even took a pacifier. Now he's drinking easily from a cup with a straw and since we will be transitioning him to whole milk I'm trying to pump so I can give him the cup at least once a day. But I'm unsure on how many ounces to give him. Any advice will be appreciated. 😊