Explanation of COI / ALC & COR
Coefficient of Inbreeding (COI):
It is a mathematically computed percentage that describes the degree to which two animals are inbred, meaning that one or more ancestors appear more than once in the pedigree. The theory is that a higher degree of inbreeding results in expression of undesirable recessive gene defects in the offspring. Some people believe that 0% inbreeding, or at least a very low number, is preferable. Sometimes in the literature, you may see COI abbreviated as IC.
Also see: https://en.wikipedia.org/wiki/Coefficient_of_relationship
Ancestor Loss Coefficient (ALC or AVK):
A related coefficient percentage is known as the Ancestor Loss Coefficient (ALC).
The Ancestor Loss is a good indication for the amount of linebreeding and inbreeding or the degree of kinship of a certain dog. The Ancestor Loss is calculated by comparing the number of ancestors that were possible in that pedigree with the actual number of different ancestors. It describes the degree to which recessive traits from ancestor generations are lost. Another way to think of it is as how many unique ancestors an animal has. If there are no duplicate ancestors, then no unique ancestors are “lost”, and the ALC = 0%. When there are duplicate ancestors, more and more unique ancestors are “lost”, and the ALC percentage goes up. A lower number is preferable. Sometimes in the literature, you may see ALC abbreviated as AVK, which stands for the German word AhnenVerlustKoeffizient.
A 6-generation pedigree contains 126 dogs. If this pedigree really consists of 126 unique dogs, then we have NO Ancestor loss (0%). A pedigree with some inbreeding might have only 114 unique dogs in these 6 generations, this equals to an Ancestor Loss of 10%.
Coefficient of Relationship (COR):
Another related coefficient percentage is known as the Coefficient of Relationship (COR). It is only calculated for two animals being considered for a potential breeding, and it gives an indication of “how related” those two animals are. A lower number is preferable. Sometimes in the literature, you may see COR abbreviated as RC.