Estimation of genetic and phenotypic parameters in a closed ...

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as 0.31 and 0.40 by Edwardsand Omtvedt (I97L) and Srviger et al. (L979),
respectivery. Research on the }{anagra conducted by Roy et al. (1968)
reported herítabilíty estimates of 0.501-0.16, 0.35+0 .L2 and 0.5610 .22 for
carcass length, carcass backfat and loin eye area, respectively.
II.
Correlations among traits
Snith et al. (L962) estimated heritabÍlities
and correlatíons among
35 carcass measurements and scores from record,s of L936 British Llhite
bacon pigs. The authors found that phenotypic and genetíc correlations
behave sinilarly. The genetic correlatíons are of the same sign as
phenotypic correlations in most cases, whí1e the absolute values of
genetic correlations rÀ7ere higher than phenotypic correlations.
There
were high correlations among traits from one particular characteristic
of the pÍg such as shoulder fat thickness and mid-back fat thickness.
The dressing-ouË percentage shor,¡ed positive correlations with backfat
thickness and eye muscle area.
Strith and Ross (1965) estimated heritabilitíes and correlations
among 26 performance and carcass traits from data involving 21296 British
Landrace pigs. The genetic parameter estimates r^7ere quite similar to the
f igures reported by Sinith et al . (L962) on Large ltlhíte pigs.
Jensen et al. (L967) found that average backfat thickness rùas not
correlated phenoÈypically or genetically i^rith loin eye area, rvhile the
percent lean cuts was highly positively correlated r¿ith average backfat
thíckness and was moderately negatively correlated with loin eye area.
Arganosa et al. (1969) estimated the genetic and phenotypic correlaËions
among 13 carcass traits from 650 pigs and showed that selection