Animal Molecular Breeding, 2013, Vol.3, No.2, 4
-
15
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Research Report
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Estimation of Genetic Parameters and Evaluation of Sires for Growth and
Fleece Yield Traits Using Animal Model in Chokla Sheep
Ravindra Kumar , Singh C.V. , Barwal R. S.
Department of Animal Genetics and Breeding, College of Veterinary and Animal Science, G.B. Pant Univ. of Agriculture and Technology, Pantnagar- 263145,
Distt. U.S. Nagar (Uttarakhand)
Corresponding author email:
cvsingh2010@gmail.com
;
Authors
Animal Molecular Breeding, 2013, Vol.3, No.2 doi: 10.5376/amb.2013.03.0002
Received: 22 Feb., 2013
Accepted: 5 Mar., 2013
Published: 21 Mar., 2013
Copyright: © 2013, Kumar. This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Kumar, 2013, Estimation of Genetic Parameter sand Evaluation of Sires for Growth and Fleece Yield Traits Using Animal Model in Chokla Sheep, Animal
Molecular Breeding, Vol.3, No.2, 4
-
16 (
doi: 10.5376/amb.2013.03.0002)
Abstract
The data on 1 214 animals progeny of 110 sires of Chokla sheep maintained at CSWRI, Avikanagar, Rajasthan were used
in the present study considering the traits birth weight, weaning weight, 6 months weight and first greasy fleece yield. The least
squares means were (2.81±0.02) kg, (12.12±0.11) kg, (16.91±0.13) kg and (0.95±0.01) kg under model 2 and (2.82±0.02) kg,
(11.87
±0.10) kg, (16.86±0.12) kg and (0.96±0.01) kg, respectively, under model 8 for birth, weaning and 6 month weight and first
greasy fleece yield. Multivariate REML analysis has estimated slightly higher coefficient of variation than the univariate and model 8
analyses. The fixed effect of year had highly significant (P<0.01) effect on all the traits studies under model 2 and model 8 analysis.
The differences in body weight traits at birth, weaning and at 6 month of age due to sex were highly significant (P<0.01). On first
greasy fleece weight, sex had significant (P<0.05) effect under model 8. Male lambs were heavier than female lambs at all ages and
produced more wool than females. The sire effect accounted for more variation under model 2 than model 8 for all traits except birth
weight. The coefficients of multiple determination under model 8 were, 13.32%, 30.80%, 33.52% and 26.11%, respectively, for birth,
weaning, 6 month and first greasy fleece weights. The higher variation at 6 month weight suggests applying intense selection
pressure at the age of 6 month. The sires have evaluated and ranked on the basis of solutions obtained through univariate and
multivariate REML using animal model and BLUP value for sire effects under model 8. The superiority of the best sires were around
5%
for the body weight traits under BLUP
1
but above 17% under BLUP
2
and BLUP
3
.
In BLUP
2
and BLUP
3
,
more than 64% animals
were superior to the population mean for body weight traits. The superiority of the best animals (as per cent of the raw mean) was
above 19% under BLUP
2
and BLUP
3
for body weight traits but this value was 18.21% (BLUP
2
)
and 15.18% (BLUP
3
)
for first greasy
fleece yield. From these results, it was observed that the REML using animal model could be used to evaluate the animals along with
their sires and dams.
Keywords
Sire evaluation; Animal model; Best linear unbiased prediction; Chokla Sheep; Growth; Fleece
Introduction
The sheep population in India is estimated to be about
71.56
million (2007 livestock Census) ranking third in
the world, and is about 6.13% of the world population.
About 0.369 MT of Mutton, 0.459 MT of wool and 40
M. kg of skins are produced annually. There are 42 descript
breeds of sheep, distributed in various agro-climatic
zones of the country. About 15.64% of the Indian
sheep population are found in Rajasthan (2007 Census)
which is the major sheep rearing state in India.
Chokla sheep produce fine carpet wool compared to
all the other Rajasthan breeds. It is also known as
Rajasthan Merino. Population of Chokla sheep was
0.886
million during 2007 census. It is apparent that
number are declining due to natural reasons and large
scale crossbreeding programmes for converting
Chokla for apparel wool production. If the economic
traits are to be included in a breeding programme,
accurate estimates of breeding values will be needed
to optimize selection programmes. In order to make rapid
genetic progress in performance through selection for
traits of economic importance in sheep genotypes,
selected animals must be chosen for their superior breeding
value (The genetic worth of individuals as parent)
(
Bichard, 1988, Falconer, 1989; Nicholas, 1987). There