Yep, exactly what you said, lol ;) Thats pretty much it, calcium, proteins, nutreints and sugars that are very beneficial to the microbial life in the root system as well as the plant itself. Apparently its also good coz it'll kill any pests and spores in the soil (although I've just discovered this as a bonus, lol).. I read on a farming site that it increases yields on crops by upto a third, so I tried it on my weed, lol. What i can say is that I had the best harvest ever, most healthiest plants and my record yield from a single plant - 226 grams of dried cured bud. I read something about a farmer who had some excess that he needed rid of, so he dumped it on one of his fields. the next season it was greaner an yielded much more.. thats where I started, lol. There's plenty of stuff on the net about it, and there's a thread on here somewhere as well.
Yeah I use just the milk straight out of my fridge, lol, whatever I have, usually semi-skimmed. I've read that it's best straight form the cow, unpasturised, which would make sense,.. but even the green-top bottles I use out my fridge seem to work wonders :)