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

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moderately heritable while carcass length, total fat thickness, loin
eye area, grade index, ham surface area, percent predicted yield and
adjusted age to market weight were highly heritable.
III.
Phenotypic correlations
Phenotypic correlatíons among the eleven traiLs are
summarized in Table 19.
Carcass length \,Jas negatively correlated wíth shoulder fal thickness'
mid-back fât thickness, loin fat thickness, loin and ham surface
area' and age to market weight, but was positively correlated with carcass
grade. The correlations betr¿een carcass length and percent ham
weight and predicted yield were negligible.
These findings indicate
that longer pigs should have l-ower back fat, smaller loin eye and ham
surface, faster growth rate and higher carcass grade index. This
finding was in good agreement wíth most reports from previous research.
The relationships among the back fat thickness measurenents were al-l
positive and the values ranged from 0.32 to 0.53. similar results
have also been reporred by Smirh et al. (Lg6Z).
Loin eye area !/as negatively correlated with all three back fat
thickness measurements, but was positively correlated wÍth grade, percent
ham weight and ham surface area and highly positively related to
percent predicted yield.
The association between loin eye area and
age to market weight was positive but low in magnitude. The phenotypic
correlation coeffÍcients between loin eye area and back fat
thickness, percent predicted yield and age to market weight reported.
from the present study were fairly
similar to the reports from Smith
et al. (1962), smith and Ross (1965), Jensen er ar. (1967), Arganosa