Computation of inbreeding and kinship coefficients on extended pedigrees

Methods of computing Inbreeding and kinship coefficients from pedigree information are reviewed. Two main approaches to the problem of computing inbreeding coefficients for several thousand individuals in pedigrees of more than 10 generations are compared: an iterative algorithm of Quaas and Henderson, and a modification of a path searching algorithm of Stevens. Analysis of 10 Standardbred stallions with pedigrees extending to 30 generations, emphasizes that remote inbreeding can make a substantial contribution to present relatedness and that use of methods that limit exploration of pedigrees to a shal low depth carries the risk of considerably underestimating the degree to which individuals are inbred.