PHOTO COURTESY OF DRUID'S DREAM ACRES LLC
WHAT IS COI?
So what exactly is COI? COI stands for Coefficient of Inbreeding, or put another way, how closely related a set of individuals are. The exact percentage you get from the calculator is an attempt to mathematically figure up what the likelihood an individual has of receiving two identical alleles from the same ancestor. The calculator that we are using here uses the formula developed by Sewell Wright, an American Geneticist that had an extensive career in animal breeding and population studies both with livestock and other species.
COI is one of the many tools available to us for managing the selection and breeding of Idaho Pasture Pigs. It should not be used as your only tool, but as one of the many things you look for as a breeder in making the best pairings on your farm to further the refinement of our standards and get an idea of the risks involves with each possibility. Keep in mind that it is not always a low number or 0% we look for, though that is the case most of the time, but that there are often specific times that a higher number might be desired.
COI can be a delicate thing, where the higher the average individuals percentages we go as a breed the more likely we are to face issues with fertility, growth rate, and genetic defects, but the lower we go the less chance we have at achieving the generalized uniformity that we want to see across the breed and especially in our feeder groups. Some good guidelines to keep in mind are that around 0% we will see very little conformity, but also very little issues with growth, fertility and defects, and once we hit 10%+ we begin to notice drastically higher instances of these issues, but much more uniformity among our litters.
One little side note - there being that “Uniformity” does not necessarily mean “Conformity to the breed standard”, it just means that the individuals in that group will all tend to look more similar to each other. As a breed a good general guideline would be to aim for the bulk of individuals to hit within 2-5% to have the genetic diversity we need but to also maintain that link breed wide that creates that uniformity. There will and should be the occasionally groups that hit 0-1% which will act as outcross sources bringing in hybrid vigor between tighter bred groups, and also occasional groups in the 6-15% range that act as reservoirs of exceptional genetics bred tight to solidify traits of certain exceptional individuals or lines (more on that soon in the article on Linebreeding).