Verena Gonzalez Lopez, 2011 - Institut für Tierzucht und Tierhaltung ...

Discussion
The aim of this study was to evaluate the genetic connectedness between five
different German herdbook populations of Piétrain pigs using pedigree information.
An important prerequisite for detecting genetic ties between populations is the unique
identification of all animals across the five herdbook organizations. Unfortunately, this
was not fulfilled in this study. Identification codes vary among herdbooks and
imported boars receive new identification code. Consequently, it was not possible to
assign original identification to imported boars so that genetic ties could be quantified
only about the parental information. This may lead to underestimation of the genetic
links between the populations, because maybe the imported boars were already
used in original herdbook population with original identification number. Therefore, it
is recommended to establish a uniform identification system with unique life numbers
for all animals in future.
Analyses of pedigree completeness and inbreeding using each herdbook pedigree
file separately as well as the entire pedigree provided a first insight into the genetic
ties between the populations. The herdbook populations in LS and NRW showed a
lower pedigree quality compared to the other populations. The low pedigree quality of
NRW can be explained by the fact that the pedigree file did not include all farms,
because some farmers have switched to another breeding organization.
Furthermore, in 2006 one of the largest farms in NRW was culled because of swine
fever and newly established with foreign animals afterwards. In general, the quality of
pedigrees was lower than those reported for dairy cattle breeds (Sölkner et al., 1998;
Hagger, 2005; Sörensen et al., 2005; Honda et al., 2006) and horse populations
(Zechner et al., 2002; Valera et al., 2005; Cervantes et al., 2008; Hamann and Distl,
2008). One reason might be the relatively short period of traceable electronic
recordings in the herdbooks (since 1979), regular importation of boars without
complete pedigree information as well as a high proportion of missing pedigree
information. The highest pedigree completeness was observed for the whole
pedigree file which suggests genetic links between populations. The comparison of
the whole and each pedigree file showed that imports and foreign AI-boars markedly
decreased pedigree completeness of herdbook populations. Thus, a general
pedigree would provide additional genealogical information for each breeding
organization.
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