The American Bulldog shares its history and ancestry with a number of other bulldog breeds. It also inspired a number of breeding programs some of which resulting in new rare breeds. The very existence of these bulldog breeds/breeding programs shows the impact the Bulldog has had in the canine world.
The principal architects of today's American Bulldog are Allen Scott and John D. Johnson. In 1970, John D. Johnson and Alan Scott first registered the American Pit Bulldog with the NKC, and later renamed it to the American Bulldog to avoid confusion with the American Pit Bull Terrier. Prior to that the dogs were known by a variety of different regional names: Southern White, Hill Bulldog, Country Bulldog, White Bulldog, White English Bulldog, English White, and commonly just "Bulldog".
As well as having varying names according to region, they also had local bloodline variations in appearance and size and also differences according to the tasks intended of them by their breeders and this is part of the reason why the breed conformation standards laid down by the registries allow for such a wide variation in type.
Initially Scott and Johnson had similar dogs and they freely bred and traded dogs with each other. Johnson's Dick the Bruiser and Scott's Mac the Masher were their foundation dogs. These two dogs were Old Southern Whites. Alan Scott and John D Johnson scoured the mountains and valleys of those Southern states looking for bulldogs and buying up those that they liked and they began a breeding program together.
Later on they had a falling out and JDJ began to develop and refine his trademark heavier-built style of bulldog. From the breeding programs of these two men, two distinct strains have emerged, commonly called the Johnson type or the Bully/Classic class and the Scott type or Standard/Performance class.
The main registries have subdivided the breed standard into these two distinct phenotypes, but these distinct types having diverged and having been diluted it is now more appropriate to talk about 5 types:
1. The Standard / Performance / Working / SCOTT Type:
The Scott type looks like a large, coarse, leggy, white Pit Bull. They are lighter weight than the Johnson type and have a very muscular athelic look and their front legs are under their body, not thrown out to the sides.
This makes the standard type American Bulldog very agile and structurally sound. They have a very strong prey drive and can be dog aggressive, which is exactly what American Bulldogs needed 300 years ago to protect the farm from wolves and coyotes, and to do catch work.
The Scott type has a closer underbite and longer muzzle too. Weight generally from 27 to 45 kg. Well-known lines include Scott, Hines, Kerschner, Koura, Stover, and Williamson among others.
2. The Bully / Classic / JOHNSON Type:
The Johnson type resembles an athletic, tightly built, white Bullmastiff. As compared to the Scott type it is a larger, wider dog with more bone, pendulous lips, and undershot jaw, facial wrinkles and a shorter muzzle.
In the 70s John D. Johnson bred two of his American Bulldog females (King's Lady Grace and Johnson's Sugar Doll) to English Bulldog West Champ's High Hopes. This created Johnson's Sugar Doll 3 and Bullmead's Queen who were both half English Bulldog. The famous Johnson American Bulldog Johnson's Incredible Mean Machine was 30% English Bulldog and foundation stock for most Johnson American Bulldogs today. This has made the Johnson type American Bulldog somewhat less athletic and more bully in appearance. Weight for males can be 55 kg plus. Mr. Johnson has branched away from the American Bulldog in 1998 to create the JDJ bulldog, which is a very tall dog with a "Standard type" body and a "Bully" head. Some claim this is now to be considered a different breed, registered with John D. Johnson.
3. The Painter/Margentina Type:
In the late 1970s, Joe Painter, Margentina, Tappe and others developed a second performance strain of American Bulldogs that was unfortunately used in the dog fighting arena. They are of an even smaller size, 25 to 35 kg.
This American Bulldog line came from using inbred Johnson's Dick the Bruiser females that were small between 20 to 30 kg. They were bred to Larry Wrights Rounder and Alan Scott's Big Bucks. The Rounder dog came from G.L. Williamson's Big Joe and Tuck's Tiger Lady who was 50% Mac the Masher.
It is widely rumored that Margentina and Trap infused Pit Bull Terrier blood into the pure Joe Painter line. This was probably due to the color in these dogs. However some of the dogs Joe Painter already had that color in them.
A couple of their more famous dogs were Painter's Zeke and Margentina's Sargent Rock.The Painter/Margentina strain was heavily inbred and had some problems, though through judicious outcrosses, the Painter strain has made valuable contributions to the breed as a whole.
4. The "Old Southern Whites" Type.:
One can still find dogs referred to as "White English" among countrymen that never have heard about Mr. Scott or Mr. Johnson. This is a term for the original country bulldogs that are not descended from any of the modern lines, i.e. breeds strains with no infusion of blood from the common American Bulldog lines.
The reverse is in fact the truth; that is to say Old Southern Whites were the raw material that Scott, JDJ and others started out with when they got their foundation dogs.
Southern Whites are still used by country folk in the deep south, some of whom have probably never heard of Mr Scott or Mr Johnson or the term "American Bulldog". Often their families have bred these "White English" for generations and these are the dogs that some claim should be named "The true American Bulldogs". A few breeders still use pure Southern White lines in their breeding programs and they can be a useful source of fresh genetic material for established bloodlines.
5. The "Hybrid" Type:
These are basically bulldogs whose blood-lines are a mixture of standard and bully types, with the goal being to distill the best features of both. Today most bulldogs are probably in this category. Some notable successful breeders of hybrid lines include Kyle Symmes (Sure-Grip), Matt Boyd and Greg Souza among many others. Hybrid dogs have excelled in competition in the States, especially Schutzhund and similar disciplines.