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Assessment of Changes in Estimated Breeding Values Caused by Varying Genetic Connectedness between Two Flocks
The number of link progeny from a single external sire was varied from 0 to 4049 (50%) of newborns in two flocks with otherwise identical pedigree (35153 animals) and weaning weight (WWT) records (25889 observations). The WWT records of all link progeny in one flock were artificially increased by 3 kg, creating a known genetic difference between the flocks. For 28 scenarios, representing varying numbers of link progeny in both flocks, a univariate single-trait model was used to calculate estimated breeding values (EBVs) for WWT. Results showed that mean flock EBVs diverged and across flock reranking events decreased, when link progeny numbers were increased. EBVs for top sires in both flocks changed significantly between scenarios. Adequate connectedness, defined as the stabilization of top sires in terms of EBV ranking, was found at 1000 and 500 link progeny over three years in the two flocks respectively.
Keywords:
sheep
connectedness
linkage
