We can divide pigs into two major types: Meat and Lard. Meat types of pig (also known as Bacon types) were developed to have more lean meat with moderate marbling of fat. In contrast, the Lard types of pig were developed to have large deposits of fat that could be more easily butchered from the animal in large chunks. This made rendering more easy, but also resulted in less loss of good meat. Lard types still have lots of good meat as well. Additionally, there are a few breeds that are both meat and lard types.

http://tcpermaculture.com/site/2014/01/15/domestic-pigs-breeds-and-terminology/