Animal Molecular Breeding, 2013, Vol.3, No.2, 4
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Table 3 Coefficient of variation (C.V. %) under model 8,
univariate and multi variate analysis
Traits
BWT
WWT
6
WT
GFYI
Model 8
16.40
20.42
17.63
29.75
Univariate
16.83
20.97
18.11
30.31
Multi-variate 17.47
24.36
21.45
34.31
Model 8 (Table 5). Similar observations were reported
by Malik et al
.
(1971),
Chaudhary and Malik (1972)
and Kushwaha et al
.
(1996).
The significant effect of
year of birth on the traits studied revealed that
breeding, feeding and management practices were not
followed similar at this farm during different years.
The farm is situated in Arid Zone and affected by
draught in different years. Least squares means
revealed that the production performance of sheep
lambs in year 1979 was poor for all the traits.
However, highest values were observed at different
age and fleece yield after 1987. It may be possible due
to change in grazing management system. One
possible explanation for the differing body weight at
different years might be associated with variability in
forage available in pasture (Bathaci and Leroy, 1998).
In years of low forage availability, sheep spend more
energy in seeking feed, thus leaving less energy
surplus for fat deposition.
Table 4 Analysis of variance under model 2
Source of variation
D.F
Mean squares
BWT
WWT
6
WT
GFYI
Sire
109
0.291*
8.948**
13.814**
0.126**
Sex
1
2.874*
138.032**
764.569**
0.199
Year
19
0.725**
40.580**
99.977**
0.711**
Error
1084
0.217
5.576
8.507
0.078
Note: *P<0.05, **P<0.01.
Table 5 Analysis of variance under model 8
Source of variation
D.F
Mean squares
BWT
WWT
6
WT
GFYI
Sex
1
3.570**
162.127**
875.468**
0.324*
Year
19
1.169**
98.933**
165.665**
1.255**
Error
1193
0.216
5.659
8.697
0.079
Note: *P<0.05, **P<0.01.
1.2
Sex of Lamb
Differences in body weights at birth, weaning and at 6
month of age due to sex was highly significant. Sex
had a significant effect on GFYI under model 8 (Table
4)
but non-significant under model 2 (Table 5). The
males were heavier than the female lambs at all ages
and produced more wool than the females (Table 2).
Malik et al.
(1971)
and Arora et al. (1979) reported
non-significant effect of sex on BWT. Arora et al. (1979)
reported significant effect of sex on WWT but
non-significant effect on 6WT. Chaudhary andMalik (1972)
reported significant sex effect on GFYI in chokla.
Kushwaha et al. (1996) reported significant effect of
sex on WWT, 6 WT and GFYI in the same breed.
1.3
Sire Effect
The random effect on birth weight and highly significant
effect onWWT, 6WT and GFYI (Table 4), indicating sizable
genetic differences among sires. Singh and Kushwaha
(1995
b) had also reported highly significant effect of
sires on WWT, 6 WT and GFYI.
Sire of lamb, under model 2 of least square, accounted for
3.43, 5.94, 6.11
and 10.36% of total variation for BWT,
WWT, 6 WT and GFYI, respectively. The corresponding
values under model 8, were 3.70, 4.63, 4.04 and 3.62
(
Table 6). Burfering and Kress (1993) also reported 8.3%
and 8.8% variation in birth and weaning weight, respectively
due to sire in sheep. The sire had accounted more variation
under model 2 than model 8 for all the traits, except BWT.
With the advance of age the variation accounted by sire
was increased under model 2, therefore, these may be
some confounding among traits, which increased sire
contribution in total variation with the advance of age.