Registered Dexter cow and 4+month old heifer calf. Cow is 3 years old and this is her second calf. We have been using her as a family milk cow, separating the calf for about 8 hours during the day. She gives 1-2 quarts for the 8 hours (though I really notice an increase in the last couple of hours, so I'm sure she would give quite a bit for a 12 hour separation). She stands nicely for milking.