Document Type : Original Article
Authors
1
Production Department, Faculty of Agriculture, Mansoura Jniversity, El-Mansoura, Egypt.
2
nimal Production Research Institute, Ministry of Agriculture, Dokki ‘3za, Egypt.
Abstract
A total of 1968 records for 706 Rahmani ewes were coflected from El-Serw
ntal Station (North Nile Delta) belonging to Animal Production Research
Ministry of Agriculture, Egypt, during the period from 1991 to 2001.
(enetic parameters and breeding values for the first lambing and lifetime
ri traits were investigated. The studied traits of the first lambing included
of lambs born per ewe lambing (NLB), number of lambs weaned per ewe
(NLW), litter weight at birth (LW B) and litter weight at weaning (LWW). White,
number of lambs born (TN LB), total number of lambs weaned (TN LW), total birth
of lambs (TLWB) and totI weight of lambs weaned (TLWW) per ewe’over six
cng opportunities were used as lifetime production traits. Traits studied were
ayzed by using single-trait animal model analyses. The overall means and
riard dêviations (SD) obtained in the current study for NLB, NLW, LWB and LWW
r first lambing were 1.13, 1.09 lamb, 3.35 and 16.17 kg, respectively. White, the
rafI means of TNLB, TNLW, TLWB and TLWW were 3.38. 3.08 lamb, 10.59 and
72 kg, respectively.
Heritabilities for NLB, NLW, LWB and LWW in the first lambing obtained ¡n the
rent study were 0.13±0.06, 0.08±0.06, 0.15±0.09 and 0.09±0.06, respectively. The
¿stmates obtained in the current study were 0.11±0.06, 0.08±0.06. 0.13±0.07 and
:10±0.08 for TN LB, TNLW, TLWB and TLWW, respectively. The genetic correlation
xng the first lambing traits ranged between 0.63 and 0.95, while it ranged between
:95 and 0.99 among lifetime production traits, but the genetic correlation between
erent first lambing and different lifetime production traits were ranged from 0.12
d 0.45. The breeding values of first lambing (EBV) for all animal were 0.40, 0.22
mbs, 1.01 and 2.82 kg for NLB, NLW, LWB and LWW, respectively, while the
xrresponding values for sire were 0.34, 0.22 lambs, 0.78 and 2.5v kg, respectively.
Soearrnan rank correlations among first lambing traits were ranged between 0.39 and
D.82 for all animals and from 0.47 to 0.81 for EBV of sires. Also, higher rank
Dorrelations among different lifetime production traits were recorded.
The obtained low to moderate heritability estimates, high coefficient of
.-ariations and the wider range of animals and sires breeding values for different traits
studied ¡n the present study, especially lifetime production traits, indicating potential
for genetic improvement of lifetime traits of Rahmani sheep.
Keywords
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