It seems that the principal crosses used with the Khoikhoi dogs were Greyhound, Bulldog and Pointer. But it´s known from Selous that in 1885 Nellis had a deerhound- like dog- in the other words a large, rough-coated Greyhound. The data also suports statements, that Nellis used Airedale and Irish Terriers and Collies. He also used the terriers and buldogs -breeds which we know are certainly part of the Ridgeback gene pool.One might infer that Fox Terriers and Boarhounds (Great Danes) were also used at this time, but there is not direct evidence, that van Rooyen used those breeds.
Van Rooyen ´s criteria in breeding dogs were very simple:
A good dog was one which survived.- a bad one was one which did not.
Of the good ones, some would have stood out for their antagonism and courage to face lions and their speed, endurance agility and cunning in harrying them. By and large, the Khoikhoi dog crosses produced both ridges and hatred for lions. Whatever deliberate breeding program Nellis undertook to build on those features, performance came first - apperance, except as it influenced performance - a pooor second. His selection would have been based on and second to natural selectioon.
The breeds used by van Rooyen for breeding had some desirable and undesirable features.