Sf. Guo et al., Bayesian analysis of lifetime performance and prolificacy in Landrace sowsusing a linear mixed model with censoring, LIVEST PROD, 72(3), 2001, pp. 243-252
Factors affecting variation of length of productive life (LPL) and lifetime
prolificacy (LTP) in Landrace sows were investigated. Herd life and prolif
icacy records were from 2616 daughters of 301 sires born in a nucleus herd
between 1990 and 1996. Records from sows sold to other farms for production
purposes were treated as randomly censored. Factors studied were year-seas
on of herd entry, age at herd entry, litter size at first parity (for LPL)
and sire of the sow. Additional censoring rates of 25 and 35% were created
to assess influence of censoring on inferences. LPL, log(LPL) and UP were a
nalyzed using a linear mixed model with censoring. Age at herd entry did no
t affect the traits studied. Sows with smaller litters at first parity had
a higher risk of being culled. Posterior means of heritability of LTP, LPL
and log-LPL were 0.22-0.25. Intra-trait correlations between sire evaluatio
ns at the three censoring rates ranged between 0.69 and 0.96. Estimates of
sire transmitting abilities obtained with censored records removed from the
analysis were in less agreement with evaluations obtained with the actual
data set than those found with the artificial censoring rates. (C) 2001 Els
evier Science BY. All rights reserved.