In-breeding vs Line-breeding
To understand the history of "in-breeding" and "line-breeding" we don't have to look at other breeds of dogs, rather look to old pedigrees within the Border Collie breed.

Isolated islands, quarantine rules, and being tied to working farms 24/7, in Great Britain there were not a lot of dogs years ago. Popular dogs were bred often, and crosses were made down the line with some dogs going back to individuals such as Wiston Cap many, many times. Location itself caused people to "inbreed" at times or sometimes to breed within lines--"line breed"--crossing with neighbors' lines of dogs. In the early days in the U.S. this system was also used caused by lack of numbers of dogs, location, lack of ease of transport, and farmers and ranchers being tied to the land.

The only clarification I wish to express is that as I learned from breeders in the late 50's, early 60's, "inbreeding" is breeding to close relatives to various degrees: first--mother, father, sister, brother; second--grandparents and first cousins; third--great-grandparents and second cousins; etc. "Line breeding" meant that a person had developed a "line" of dogs (generally related, sometimes "inbred," to a particular degree, and that certain breeder's "lines" of dogs were crossed to produce offspring that complimented, intensified, or compensated for certain inherited tenancies.

Since about the 70's, the term "in-breeding" has been used for close breedings (mother, father, sister, brother), and "line breeding" used for breedings of less related individuals. Geneticists generally consider all breedings of related individuals as in-breeding.

Inbreeding can intensity poor traits or health problems, but can at the same time intensify ("set") good traits and good health. Livestock breeders have used in-breeding and line-breeds for ever to produce predictible outcomes of offspring. Knowing when to intensify and when to outcross is the skill. Honesty to one's self and others can help to breed healthy and talented dogs. Time, study and dedication (folllowing one's pups in each generation) over many years helps Since many genes remain hidden for generations, being able to predict this without a crystal ball is an art, or to some degree luck or an answer to prayer!!!

In a 1939 book by E.L. Hagedoorn, a Dutch consulting geneticist to breed societies and countries around the world, I found a closing quotation:

"In the production of economically useful animals, the showring is more of a menace than an aid to breeding. Once fancy points are introduced into the standard of perfection, the breeders will give more attention to those easily judged qualities than to the more important qualities that do not happen to be of such a nature that we can evaluate them at shows. Showing has nothing to do with utility at all, it is simply a competitive game."