Opening the studbook, one generation at a time.

What opening the studbook means

A closed studbook admits only animals whose parents are already in it. Opening it, even briefly, lets the board admit animals it would otherwise refuse. Published rules describe two kinds of opening, and a board should say which one it means before it votes on anything else.

• Admitting animals of the breed that lack accepted papers. These animals are believed to be the breed already, but their ancestry is not in a register the club recognises. Under the FCI Internal Rules, such a dog can be entered in an appendix to the studbook after an FCI judge approved for the breed has assessed it. The Basenji Club of America’s native stock program admitted animals imported from the breed’s homeland after evaluation and a club vote.
• Admitting a deliberate cross, then breeding back. Here the outside animal is known to be another breed or a cross, and its descendants are bred back to the original line until they meet the board’s threshold. The Dalmatian backcross project began in 1973 with one cross to a Pointer, to bring a normal uric acid gene into the breed. Many cattle associations run open upgrade registries on the same principle.

The arithmetic in this guide applies to the second kind. The first kind is usually counted in generations of registered ancestry rather than in percentages, and the conditions below show both.

Why boards consider it

There is no single signal. Boards usually look at several together: average COI rising across birth years, the number of effective founders falling, and a few sires producing a large share of registrations. Effective population size (Ne) brings these together. The Royal Kennel Club describes it as the size of the gene pool, says an Ne above 100 is sustainable, and says an Ne below 50 is considered at high risk of the harmful effects of inbreeding. The FAO cites an Ne of 50 or more as the recommendation for breed conservation, which corresponds to inbreeding rising by about 1 percent per generation.

A study of every breed registered with the UK Kennel Club from 1980 to 2014 found Ne below 100 in 68 of the 116 breeds it could measure, and below 50 in 29 of them. It found popular sires in every breed. The Royal Kennel Club recommends using more males and females from different parts of a breed first, and says outcrossing helps but is not a silver bullet. Opening the studbook is one option among several, and the decision belongs to the club, under its bylaws.

The arithmetic, generation by generation

Each offspring carries the average of its parents’ % of original line. A foundation animal starts at 0% and an original-line animal at 100%. Bred back to the original line every generation, the outside share halves each time. After n generations bred back, what is left of the outside share is 100% halved n times, and the original line is the rest. Breed associations often write the same numbers as fractions: 7/8 is 87.5%, 15/16 is 93.75% and 31/32 is 96.875%.

Work out any line with the outcross calculator.

A worked example

The board of the Larkspur Fell Registry admits one foundation animal, Desert Wick, from source registry A. Its rule, set before the vote: a female is fully registered at 87.5% of original line, a male at 93.75%. Each descendant is bred to an animal of the Ridgeview line, whose average COI is 18%. The expected COI column assumes the foundation shares no ancestors with the line and every mate is an average Ridgeview animal, so each figure is the parent’s share of original line multiplied by the line’s own 18%.

Sample data.

Two things show in the table. First, expected COI climbs back toward the line’s own 18% as the original-line share rises, so the diversity an outcross adds is greatest in the early generations. That is why boards admit more than one foundation animal and spread their descendants across many mates. Second, not every mating goes to an original-line animal. If the F2 at 75% is bred to an F3 at 87.5%, the offspring carries the average, 81.25%, and meets neither threshold. Its own offspring by an original-line animal reaches 90.625%: enough for a female under this rule, not for a male. Write the rule as a share, not a generation number, and these cases answer themselves.

Conditions boards usually set

Published rules from registries for several species attach a similar set of conditions. The examples below are what each source says. They are not recommendations for your breed, and your parent registry’s rules may decide some of them for you.

Writing the decision down

Clubs differ in how they decide: some vote at a general meeting, some delegate to a breeding committee. Whatever your bylaws say, write the decision down with its reasons so the next board can read it. I would keep one record per opening, with these parts.

• The motion, word for word, with the date, the meeting, who moved and seconded it, and the vote count.
• The kind of opening: animals of the breed without accepted papers, or a deliberate cross bred back.
• The rationale: the figures the board relied on (COI by birth year, effective founders, the share of registrations by the most-used sires, Ne if you have it), the date they were drawn, and who produced them.
• The criteria: who may be admitted, inspection and who inspects, DNA and parentage, health tests, the threshold for full registration by sex, and the rounding rule.
• The register mechanics: where descendants are recorded until they qualify, and how their certificates show it.
• The window: the date admissions open, the date they close, and a cap on the number of foundation animals if there is one.
• The review date, and what would trigger an earlier review.
• Who records it: the officer who keeps the minutes, the registrar who keeps the foundation files, and where both are kept.
• For each foundation animal: the source registry and its number, the documents received, the inspection report, DNA results with the lab and method, and the date the board approved it.
• The line each descendant belongs to and its % of original line.
• Any approval your parent registry must give, and the date it was given.

After the vote

• Publish the rule to members before the first admission, so breeders plan matings against the threshold you set.
• Review the program on the date in the motion: how many foundation animals were admitted, how many descendants are registered, and whether COI and the share of registrations by the most-used sires have moved.
• Close the window on the date in the motion, or extend it by a new recorded vote.
• Keep the foundation files for as long as any descendant is in the studbook. A question about an animal at F5 leads back to the F0 file.
• Decide how the club will read COI for outcross descendants. The early generations carry low expected COI by design, so a band that flags only high values will not show what the program is doing. The board sets its own bands for its breed.

Common pitfalls

• Mixing the two kinds of opening. A generation count written for animals of the breed without papers does not work for a cross, and a percentage rule written for a cross does not fit animals with no known outside ancestry.
• Counting generations differently. Whether the foundation is F0 or F1, and whether a rule counts generations of ancestors or of descendants, can shift a threshold by one. Write thresholds as a share of original line, or define the count in the motion.
• No rounding rule, so two registrars record the same animal differently.
• One foundation animal, one popular sire. If most descendants trace to one admitted animal and a few mates, the opening rebuilds the problem it was meant to solve. The FAO example of two males and 100 females is the warning.
• Assuming the foundation is unrelated. If the admitted animal shares ancestors with the line, real COI runs higher than the expected COI in the worked example.
• Treating the percentage as a DNA result. It is the share expected from the pedigree. Each parent passes on a random half, so one animal’s measured share can sit above or below it.
• No sunset date, so the studbook is open by default years later.
• Not deciding what happens to registered animals if a later board reverses the decision. The AKC registered two fifth-generation Dalmatian backcross dogs in 1981, then rescinded the registration of their offspring after a 1984 club vote went against them. Descendants of the project were accepted into the AKC stud book again later. Write the status of registered animals into the motion.