The partial inbreeding coefficients, Fij, measure the probability that the alleles at an arbitrary locus in individual i are identical by descent and that the alleles were derived from an allele in founder j. The partial inbreeding coefficients of the ancestors of an individual can be seen as their "contribution" to this individual’s COI, i.e., in a full pedigree the sum of all partial COIs of all ancestors of the individual must equal the individual’s COI!
Ancestors contributing the most to an individual’s COI do not automatically have the highest inbred percentage. By being a closer relative (grandparent, great-grandparent) an animal with a low inbred percentage might have a larger contributing factor than other animals with a higher inbred percentage. The animal you selected for pedigree analysis will have most in common with the ancestors having the highest partial inbreeding coefficient.
Please note: The partial COI calculation is available only up to the 5th generation as computational requirements are too high for larger pedigrees.