>Inbreeding requires the knowledge of dominent genetics and requires the breeder to cull imperfections. Superior animals will breed superior animals. However, imperfections will be amplified as well, thus the breeder must be willing to cull.
What is the benefit of pedigreed cattle? As one looks at the papers, the informtion as to lines repeated in the pedigree point to increasing the chances of a desired trait.
In many cases seeing champion on the pedigree might be more the result of politics and feeding of the animal rather then an indication of Superior genetic traits.
You must decide your traits to which you wish to improve, then concentrate their likelihood of expression.In almost all cases of failed inbreeding, there were hidden traits not accounted for which resulted in defects.One must remember Nature desires the greatest opportunity for adaption, when we breed for traits, its likely they may not have survivable traits or lasting traits as they relate to Natural selection.
The Bell curve and statistics show this. At the two ends of the cure we measure success and failure of our breeding programs. We as breeders of improved cattle desire to shift the superior trait expression more to the superior side then the inferior side, this is a hard balancing act, but one with great potential.
Very generally, look for two lines which have concentrated traits without errors or defects. Then breed from this result to your general herd, always remembering that Nature likes diversity and Man sometimes overly selects for too few traits while breedig for type.
We have a line of horses which we have bred without appearent defect for since 1989. (See Tuhotmos and General Tibor Von Szandtner). In this case knowledge and Nature seems to have created a very pure line for type and hidden health concerns, ours seem well adapted to our conditions, while maintaining form and function.
Guppies, too, point to the use of inbreeding to produce superior genetics. ( See; studies of the late 1960's and the production of Super Dominents). In almost all cases of plant or animal modification someone has inbred for certain traits with the result they see what they wished to have expressed.
The danger of restricting the genetic material will be offspring may not have the tools to adapt to new conditions or stress factors in the environment. We pay a price for human intervention into Natures design.