I was afraid someone was going to ask that. sigh.
Ok, technically, dogs ARE classed as livestock by the USDA, and they are SUPPOSED to be regulating breeders who sell wholesale. How effective their oversight is can be open to debate.
There are a number of problems with trying to raise dogs as livestock, and they have nothing to do with J. Q. Public's image of dogs as cute little furballs. One of the problems is that dogs, by their nature, cannot be raised in confinement, or out on pasture like many other types of livestock. As pickapeppa ponted out, the dogs have to be socialized from an early age in order to make good pets. The same is true if they are intended as working dogs. if you were going to raise them for food, socialization might not be an issue, but since there is presently no legal market for dog in this country I won't even address that possibility.
You can do an internet search for puppymills, or even Backyard breeders, and find a literal TON of information. Much of it is hystrionics from bleeding heart pet lovers. BUT, beyond all of that, there are enormous costs to society when puppies who are not properly raised are dumped on animal shelters, humane societies, rescue groups, or some poor unsuspecting rural resident/farmer. There are huge costs incurred when poorly bred/socialized dogs attack children, elderly people, and other innocent victims. There are huge financial/environmental costs incurred when large amounts of canine fecal matter are not disposed of properly- this happens quite often with large scale dog breeders. With farm animals, the manure can be turned into an asset and sold as fertilizer or returned directly to the ground as fertilizer. That doesn't work with dog manure.
There are many, many problems with raising dogs as livestock. If you think you are interested in doing so, please sit down first and do the math. I would be very suprised if, after doing so, you thought you could raise dogs well and make enough of a profit for it to be worth your while.