and have hi fat content.

As husbandry goes, an animal is fed to slaughter size as soon as possible(hence all the hormone injection)

you simply can't feed pigs with garbage in cost effective husbandry and the fodders must be supplemented with things like oil cakes.

That's why china imports such a huge amount of soy and corn from US.

Soy sauce and drinks don't require 56 million tons of import from US(+15 million ton domestic production)

http://www.bloomberg.com/news/2012-02-14/china-s-soybean-imports-may-jump-to-all-time-high-on-stockpiling.html