Zaffer et al.
be done. Therefore, the present study was undertaken to
Y ijklm
= m th record of individual lambed in i th period, j th
study the effect of non-genetic factors in Dorper crossbred
season, of k th genetic group and l th sex
sheep.
m = Overall population mean
MATERIALS AND METHODS
P i = Fixed effect of i th period of lambing
Performance data on 401 animals used in the present
S j = Fixed effect of j th season of lambing
study were collected from history sheet of crossbred sheep
G k = Fixed effect of k th gentic group
maintained at Government Sheep Breeding Farm Panthal,
C = Fixed effect of l th sex
Reasi, J & K, India. The Government Sheep Breeding
l
Farm, Panthal, is located 52 kms on north-east of Jammu
e ijklm
= Error associated with each observation and assume
and lies between 33 0 05 N latitude and 74 0 5 E longitude.
to be normally
and independently distributed with mean
The farm follows semi-migratory production system. In
zero and variance (0, σ e2 )
middle of April the sheep are shifted to highland alpine
For significant effects, the differences between pairs of
pastures, at an altitude of 6000-8000 feet above sea level
levels of effects were tested by Duncan’s multiple range
and allowed to graze there up to end of September. Ewes
test as modified by Kramer (1957).
were mated in the month of August and October when
ewes were flushed on nutritive highland pastures. The
ewes were divided into groups, each group consisting of
RESULTS AND DISCUSSION
about 50 ewes. The crossbred population was developed
The overall average estimates along with standard error
for crossbreeding of different level of inheritance of
(SE) were 2.931 ± 0.034 kg, 14.490 ± 0.159 kg, 17.540
Dorper with Rambouillet sheep. There were three genetic
± 0.162 kg, 22.660 ± 0.171 kg, 29.950 ± 0.142 kg and
groups in the farm i.e., 50% Dorper inheritance, 75%
0.669 ± 0.08 kg, respectively for BWT, WWT, 6-BW, 12-
Dorper inheritance and 100% Dorper inheritance. The
BW, MBW and AWP. Lower overall estimates for BWT
performance data maintained at farm from 2001 to 2013
& WWT and higher estimate for GFW were reported in
were classified into three different periods for present
Kashmir Merino sheep (Das et al. , 2014). The coefficients
study. Growth traits included in the study were birth weight
of variations were ranged from 8.99% to 21.65% for MBW
(BWT), weaning weight (WWT), 6-month body weight
and BWT, respectively. Das et al. (2014) was reported
(6-BW), 12-month body weight (12-BW) and mature body
low CV for BWT and WWT in Kashmir Merino sheep.
weight (MBW). Data with any recorded abnormalities and
The co-efficient of variation CV (%) for different traits
outliers were excluded prior to the analysis. The mean,
under study were low to moderate indicating that there are
standard errors and coefficient of variations (CV) of all
low to moderate variations among these traits and these
economic traits like growth and production traits, were
traits can be improved with proper breeding, selection and
computed statistically given by Snedecor and Cochran
management practices.
(1968).
The least-squares means for different factors have been
All the traits under study were normalized. The effects
presented on Table 1. The overall least-squares means
of non genetic factors such as periods, seasons and sex
for BWT, WWT, 6-BW, 12-BW, MBW & AWP were
on various normalized growth and production traits were
2.857 ± 0.058 kg, 15.269 ± 0.296 kg, 17.034 ± 0.258 kg,
analyzed by least squares analysis using the technique
22.315 ± 0.298 kg, 29.375 ± 0.237 kg and 0.651 ± 0.012
developed by Harvey (1990). The following model was
kg, respectively. Similar birth weight was reported by
used for analyzing data for Dorper crossbred sheep with
Ganesan et al. (2013) in Madras Red sheep and Das et
assumptions that the different components being fitted
al. (2014) in Kashmir Merino sheep. Balasubramanyam
into the model were linear, independent and additive.
and Kumarasamy (2011) also reported similar findings of
BWT and 12-BW in Madras Red sheep. However, higher
Y ijklm
= m + P i + S j + G k + C l + e ijklm
estimates of BWT, WWT, 6-BW and 12-BW have been
Where,
reported by earlier workers (Saghi et al., 2012; Dass et
228
Journal of Animal Research: v.5 n.2. June 2015