Back during season 1, we saw a cow stampede and it seemed like they were regular animals until Applejack stopped it and they started talking in a midwest accent. Apparently they live in a barn and can be randomly milked too if Twilight's Ursa Minor battle is any indication.
So what do you think their actual role in society is? Are they subservient to ponies? Or do they just really love living in barns and being milked by them?
