Contribututions to future generations

Sue Ann Bowling

These tables are based on calcuations of the effect a subset of Shetland Sheepdogs, most of whom are in the ROM or Imports section, had on a sampling of dogs of later generations. The sample of descendants selected is Register of Merit Shelties born after the influential ancestor.

The percent column give the total percent influence, using the complete pedigree including evey dog in the pedigree born after the key ancestor, even if the dog is 20 or 30 generations back. The percent influence is calculated according to the rule that the percent influence in any given dog is the average of the percent influence of its parents. Thus a dog pred to his own daughter would produce pups with 75% influence; while a great grandson with no other links to the important ancestor would have 12.5%.

An influential dog tends to start out with a few dogs showing high influence. Gradualy the maximum influence drops off, but at the same time more and more dogs have some influence, and a point may be reached where every dog in the breed shows nearly the same influence from an important earlier dog. This point has been reached with a few dogs born in the 20's and early 30's. Downfield Ethne (who lived her life out in England) is a good example of this eventual stabilization. Ch Halstors Peter Pumpkin is an example of a much earlier stage in the influence of a dog who has an extremely large contribution on the breed as a whole.

The numbers column in the table is just that; a count of the number of times a dog appears in the pedigree. This is meaningful in the early generations, but after a few generations it depends primarily on the number ofgenerations since the dog became ubiquitous in the gene pool. Look at the page for Kilravock Lassie, for instance, who is probably behind every Sheltie alive today and has some impressive number of appearances, but whose percent contribution is quite small. There are also charts based on the pedigrees of Ch Halstors Peter Pumpkin ROM and A/C Ch Banchory High Born ROM, showing the influence on each of these two important dogs of each of the original imported Shelties.

British-bred Males:

British-bred Females

American-bred Males

American-bred Females

In addition, I have included charts for Ch Halstors Peter Pumpkin ROM and for Am/Can Ch Banchory High Born ROM showing the percentage and number influence of each of the imports on their pedigrees.