Abstract:
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 i
mplemented rotational mating scheme
using pedigree analysis. Lambs born during 2009-201
1 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 pa
thways. 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 individua
l rate in coancestry and from the
individual increase in inbreeding, respectively. Ge
nealogical parameters estimated based
on probabilities of gene origin including the effec
tive numbers of founders, the effective
numbers of ancestors, the effective numbers of foun
der genomes (founder genome
equivalents) and the effective numbers of non-found
er 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 r
ecent years were identified in the
studied population, a considerable genetic variabil
ity existed in this population due to
implementation of an efficient rotational mating sc
heme for controlling inbreeding.
Keywords:
Closed flock, Inbreeding trend,
Rotational mating scheme, Genealogical parameters.