The kid will be weaned - ie stop taking mum's milk by the autumn so the mum will need mating again, to keep up high yields
They start eating some solid food really early on, but need the immunity and nutrients of their mothers milk for all those many months.
Not many goats 'milk through' for 3 years, you'll be one lucky goatkeeper (or have paid a fortune for a proven milker-though there's no guarantee a goat that does it once will do it again!)
Sometimes we have only managed once a day milking - not by choice, but the awkwardness of the goat! She gets abit stroppy when its too hot, or wet etc etc. If you set up a routine with your goat, she may be happy for an early and late milk, at the moment we are often milking 8pm, she is happy to come out in the dark. (we call her "the goat that never sleeps!" )
ps not read the article, but will look out for it!