%0 Journal Article
%T Genetic Parameter Estimates for Growth and Reproductive Trait of Sheep for Genetic Improvement and Designing Breeding Program in Ethiopia: A Review
%A Shigdaf Mekuriaw
%A Aynalem Haile
%J Open Access Library Journal
%V 1
%N 5
%P 1-10
%@ 2333-9721
%D 2014
%I Open Access Library
%R 10.4236/oalib.1100589
%X <p class="MsoNormal">
	<span lang="EN-US">Small
ruminants in general and sheep in particular are important investments in the
highlands of Ethiopia. Genetic and environmental improvements offer an
opportunity to increase production from existing animal resources. Development
of effective genetic evaluation and improvement programs requires knowledge of
the genetic parameters (genetic variance of each trait and covariance among
traits) for economically important production traits. Direct heritability
estimates for birth weight of Afar sheep (0.13 to 0.38) and BHS (0.20 to 0.58)
using univariate analysis; for Horro sheep (0.18 - 0.32) and Menz sheep (0.46)
by fitting a multi-trait individual animal model. The weaning weight direct
heritability estimates for sheep in Ethiopia, Afar sheep (0.11 - 0.37) and BHS
(0.00 - 0.29), Horro sheep (0.10 - 0.26) and Menz sheep (0.48). Fertility,
litter size and lamb survival are the components of the overall ewe
reproduction traits. It appears that heritability estimates of these traits are
rather low and reflect the generally small genetic variance for most
reproductive traits. Moreover, litter size has a higher heritability (0.16 -
0.19) than the other components traits like fertility (0.10) and survival rate
(0.07 - 0.09) for Awassi sheep breed. Genetic correlations among most pairs of
traits were higher than the corresponding phenotypic correlations. Live weights
measured at successive ages were highly correlated, ranging from 0.61 to 0.98
for Menz sheep. Genetic correlations were also high between pre-weaning daily
gain and weaning weight for Afar and BHS sheep. Except for Blackhead Somali
sheep breed which has high genetic correlation between birth weight and weaning
weight, Horro, Menz and Afar sheep have high genetic correlation between
post-weaning weight traits. This indicates that selection for one trait
improves the other trait in those sheep breeds. In order to develop alternative
improvement program for sheep breeds in Ethiopia, estimates of genetic
parameters for economical growth and reproduction traits should be done by
designing experiments since the information on most sheep breed is
nonexistence.<o:p></o:p></span> 
</p>
%K Genetic Parameter
%K Sheep Breed
%K Heritability
%K Correlation and Breeding Program
%U http://www.oalib.com/paper/3064761