In the interests of adding to the store of common knowledge, I've been measuring.
As we aren't sharing with a calf this year, I have better data than previous efforts... At a week post freshening, Sasha is reliabily providing 6 litres of milk every day.
We have been getting the new Holstein calf to do "cleanup milking" - he gets tied to the milk stall when I'm done and slurps up what he can, so Sasha is producing a bit more than the measured amount, though not a whole lot.
All is well so far... Sasha isn't in love with the calf, but a few more sessions of cleanup milking might change her mind. We shall see!
I am definitely going to make cheese. Even with all of us here, we won't drink six litres a day!