Effects of multiple-sire matings on genetic evaluations, selection response and rates of inbreeding

Abstract

Multiple-sire mating is evaluated for a range of conditions, for its impact on regular genetic evaluation analyses in performance recording, and on selection response and inbreeding in breeding programs as a whole. Substitution of the average for the complete numerator relationship matrix (NRM) in the mixed model equations produced little bias in genetic trend estimates but substantial bias of inbreeding estimates. By recording sire group membership and dam identification under multiple-sire mating and using these and the average NRM in genetic evaluation analyses, it is shown that: 26–63% more genetic gain is achievable compared with selection on individual performance alone (no genetic analysis); and realised genetic gain is reduced by less than 6–24% compared with single-sire mating and use of complete BLUP analysis.