Do the definitions of “CAFO” and “factory farm” differ?

According to About.com, BloggerNews, and others, a factory farm is an AFO (animal feeding operation), and the largest, as determined by EPA guidelines, are CAFOs (concentrated or confined animal feeding organizations). But many sites, such as Socially Responsible Agriculture Project, use “CAFO” and “factory farm” interchangeably.

The Wisconsin Sierra Club site lists the baseline numbers of animals for a facility to be considered a large CAFO. It’s pretty horrifying.