Studbook information collected from 1988 to 2011 in Jafarabad breeding station of
Moghani sheep, north-west of Iran, related to 9,457 lambs were used to study the genetic
diversity and to evaluate the effectiveness of an implemented rotational mating scheme
using pedigree analysis. Lambs born during 2009-2011 were considered as reference
population. Means inbreeding and average coancestry for the reference population were
computed as 0.40 and 0.74%, respectively. The mean generation interval was 4.48 years
with a longer generation interval on dam-progeny pathways. Average equivalent complete
generation, as a measure of pedigree completeness, was 3.37. Effective population sizes
were estimated to be 226 and 276 from the individual rate in coancestry and from the
individual increase in inbreeding, respectively. Genealogical parameters estimated based
on probabilities of gene origin including the effective numbers of founders, the effective
numbers of ancestors, the effective numbers of founder genomes (founder genome
equivalents) and the effective numbers of non-founder genomes considering the reference
population were estimated as 143, 117, 67, and 126, respectively. Approximately, 50% of
the total genetic variation was explained by the 43 most influential ancestors, with a
maximum individual contribution of 3.27%. The results indicated that although some
evidences on bottlenecks and genetic drift during recent years were identified in the
studied population, a considerable genetic variability existed in this population due to
implementation of an efficient rotational mating scheme for controlling inbreeding.