The objective of the study was to estimate
genetic parameters for length of productive life
(LPL), and determine its genetic correlation with age
at first farrowing (AFF), number of piglets weaned at
first farrowing (NW), and first wean-to-insemination
interval (W2I) in the Finnish Landrace swine population.
Data from the Finnish national litter recording
scheme were utilized to estimate the genetics of LPL,
and genetic associations between LPL, AFF, NW, and
W2I. Data from the Finnish Landrace sow records were
utilized from farms that farrowed more than 20 gilts
annually from 2000 through 2005. The data set included
information from 11,222 sows, all of which had AFF
and NW information available. The sows producing the
records evaluated were daughters of 1,267 sires, and
there were 3,684 animals in the pedigree when all of
the sires were traced back to founder animals. All data
were obtained from FABA Breeding (Vantaa, Finland).
Multivariate Bayesian analysis of Gaussian, right censored
Gaussian, and categorical traits was utilized to
estimate (co)variance parameters of LPL, AFF, NW,
and W2I of the sow. From these traits, AFF and NW
were treated as Gaussian, LPL as right-censored Gaussian,
and W2I as categorical traits. Estimated posterior
means of heritabilities were 0.22, 0.16, 0.09, and 0.08
for LPL, AFF, NW, and W2I, respectively. A relatively
large proportion of variance due to farm-year interaction
was observed (posterior means of f2 ranged between
0.03 and 0.26). The LPL was moderately genetically
correlated with NW and AFF (posterior means
were –0.20 and 0.36, respectively), whereas no clear
association was found between W2I and LPL. Favorable
genetic correlations between AFF and W2I and
between NW and W2I were also observed. Additionally,
an unfavorable genetic correlation between AFF
and NW was observed in the present data set. Because
LPL is genetically associated with other economically
important prolificacy traits, it should be included in a
multiple trait swine breeding value estimation system.