The Open
Flockbook Project

Some of the terms we use throughout the website may be new to users of the OFP, or they may have different meanings in different contexts, or they may need defining to help you navigate the website without confusion or misunderstanding. This page is a work-in-progress. Please feel free to suggest other terms you'd like to have defined or explained further. You also will find definitions within specific topics elsewhere on this website.

Hypothetical Mating or Hypothetical Pedigree

Participants can receive an analysis, with all sorts of calculations, of what the characteristics of a new lamb would be depending on what ewe you breed to what ram. Many people use the hypothetical matings to see whether a breeding pair will result in a degree of inbreeding you find unacceptable. Another example is predicting coat color, horn size, light or dark phase, self- coloration, and so forth, to the extent phenotypic data is available for the hypothetical breeding pair and their ancestors. The on-line OFP provides a non- analytical, more basic version of test mating for all on-line users.


We’ve been asked whether the OFP is a “registry.” The answer is yes, it does operate as a registry, but looking at what we do and what we don’t do provides a better answer to the question.


In the OFP and for genetic analysis generally, the term "full sibling" means the two animals had the same dam and the same sire even if the two animals were born in different years. A "twin" would be a full sibling born in the same year. Similarly, animals who are "half siblings" share either the same dam or the same sire. Half siblings born the same year share the same sire but have different mothers. Half siblings born in different years have either common dams or common fathers.