Wow, I can't believe with so many expereinced goat owners on here that no one has even a suggection for your questions.
This is my first time to breed my goats while they are in milk and with my boer cross her milk production did indeed slowly drop to the point of only giving a few cups a day so I just quit milking her. But out of 4 possible breedings she is the only one that "took" so I can't give any other examples-experiences.
Maybe someone who has more experience will chime in and at least give their 2 cents worth....