My understanding is that all the cubs born in the chinese breeding facilities are mainly raised by their mothers for 6 months and removed then to be raised with other cubs so that the mothers gets pregnant the next breeding season and has cubs each year, while in the wild (and in San Diego) the females have cubs only every 2 years. I am not at all happy that the chinese still seperate the cubs from their mothers at 6 months, it is no longer necessary to produce that many cubs each year to sustain the captive population, but from the social point of view, 6 months with the mother is probably enough for a panda to learn social behavoir and that he/she is a giant panda and not a human, lol. But for release, I would always make sure the panda is raised by its mother for 1,5 years and with as few contact to humans as possible...