LLP - Why Use a 10 generation COI & up-coming breeders' meeting date and time.
- lippittlineagepres
- Jul 28
- 2 min read
Why Use a 10-Generation COI
The coefficient of inbreeding, or COI, estimates the probability that a horse inherited matching copies of a gene through ancestors shared by its sire and dam. However, the number only includes the generations examined in the calculation.
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Ethan Allen II
3 generation COI: 6.25%, 10 Generation COI: 15.0056
A three-generation COI looks for shared ancestors within a relatively short pedigree. It may show whether the sire and dam are closely related through recent ancestors, but it can miss much of the shared ancestry found farther back.
This distinction is especially important in the Lippitt Morgan. Lippitts descend from a small foundation population, and many ancestors appear through multiple branches of the pedigree. A mating may have few, or no, shared ancestors visible within three generations while having considerable shared ancestry between generations four and ten.
For this reason, Lippitt Lineage Preservation uses a 10-generation pedigree COI as a consistent comparison standard. Ten generations provide a more informative view of accumulated relationship than a short calculation while remaining practical for breeders to use.
Ten generations are not a biological stopping point. Ancestors beyond the tenth generation may still matter, and breeders may choose to examine the database’s additional generations. LLP’s use of ten generations simply gives us a common starting point for making meaningful comparisons.
A three-generation calculation is not mathematically incorrect. It answers a narrower question than a ten-generation calculation. Therefore, a 3-generation COI and a 10-generation COI should not be compared as though they represent the same information.
The practical rule is simple:
Before comparing COIs, confirm that they were calculated using the same number of generations.
COI is also only one part of evaluating a mating. It does not tell us whether a mating is good or bad, which traits a foal will inherit, or what contribution that pedigree may make to the future Lippitt population. Those questions require us to look beyond the number—and they will be explored in future Breeding in Practice notes.
The LLP offers Breeder resources, pedigree tools, and preservation planning for the future of the Lippitt Morgan.
Join the Breeders' Meeting
Topic: The Challenges of Standing a Stallion
Standing a stallion involves much more than owning and breeding a male. The discussion may include promotion, training, mare owner communication, breeding arrangements, veterinary and collection expenses, housing, safety, and the challenge of giving individual stallions meaningful opportunities within a small population.
When — Aug 11, 2026 8:00 p.m. Eastern / 7:00 Central / 6:00 Mountain / 5:00 Pacific
The meeting will be held via Zoom and can be accessed from a computer or smartphone. An email containing the link will be sent to those interested in attending.
LLP is varying meeting dates and times to accommodate breeders’ schedules. If you have a preferred day or time, please let us know so we can choose options that allow as many breeders as possible to attend.
website: https://lippittlineagepres.wixsite.com/lippitt-lineage-pr-1
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