GENETIC STUDIES ON SOME ECONOMIC TRAITS IN RAMBOUILLET x GADDI (HIMTAL MERINO) CROSSBRED SHEEP UNDER SUBTEMPERATE CONDITIONS
Loading...
Date
2016-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CSKHPKV, Palampur
Abstract
ABSTRACT
A crossbred sheep population locally named as “Himtal Merino” with 75% Rambouillet
inheritance have been evolved at Govt. Sheep Breeding Farm, Tal (Hamirpur) by crossing of
Gaddi ewes with Rambouillet rams. Data on 1204 crossbred lambs for growth and wool
production, 669 ewes for reproductive and 370 sheep for lifetime performance traits, progeny of
28 sires, were analysed by LSMLMW method using a fixed effect model to study mean
performances and effect of some genetic and non-genetic factors on performance traits. The
variance and co- variance components for genetic parameters were estimated by single trait animal
model using WOMBAT software. The overall least squares means were 3.26±0.06, 16.11±0.03,
21.82±0.06 and 26.29±0.12 kg for lamb‟s weight at birth, 3, 6 and 12 months of age respectively,
141.44±0.18 g/day for pre weaning growth rate and 63.68±0.34 g/day during 3-6 months of age,
24.53±0.45 g/day during 6-12 months age and 36.64±0.38 g/day over 3-12 months of age post
weaning body weight gain. The means were higher for HTM than R x G and R x RG lambs.
Higher growth rate was achieved during pre weaning than post weaning stages. The mean age at
first breeding and first lambing were 924.25±0.78 and 1070.51±0.48 days respectively. For wool
production traits, the means for age at first shearing (AFS) was 184.62±0.14 days, shearing
interval as 180.29±0.07 days, first and second annual greasy fleece were 1823.30±1.59 g and
2163.83±1.83 g respectively, second annual yield being higher than first. The mean longevity was
1210.72±26.39 days with productive life span of 945.84±26.39 days. The heritability for growth
traits was low to medium being 0.19±0.05, 0.14±0.04, 0.20±0.05 and 0.06±0.03 for birth, 3, 6 and
12 months of age body weights. High heritability (0.62±0.01) was estimated for pre weaning body
weight gain. For post weaning body weight gains, heritability were 0.14±0.04 for 3-6 months,
0.15± 0.04 for 6-12 months and 0.10±0.04 for 3-12 months of age. The heritability for various
reproductive traits were low to moderate with estimates of 0.22±0.02, 0.02±0.10, 0.08±0.11,
0.07±0.10, 0.21±0.04, 0.31±0.06, 0.16±0.03, 0.18±0.05 for age at first breeding, age at first
lambing, first lambing interval, second lambing interval, first service period, second service
period, first gestation period and second gestation period respectively. For wool production traits,
low heritability of 0.19±0.07 and 0.18±0.06 was estimated for age at first shearing and shearing
interval and low to moderate heritability of 0.21±0.06, 0.14±0.04, 0.24±0.11, 0.23±0.09,
0.31±0.08 and 0.29±0.07 for fleece yield at first, second, third and fourth clips, first and second
annual fleece yields respectively. Most genetic and phenotypic correlations among growth traits
were positive and high. Positive genetic correlations were observed among various wool
production traits and growth traits and wool production traits indicated scope for selection on basis
of early expressed growth traits.
Description
Keywords
null