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Genetic Evaluation and Factors Affecting Post Weaning Growth Performance and Body Dimensions of Awassi Lambs.

Yousif, M. S. Al-Barzinji 1*, Haval I. A. Gardi1

1Dept. of Animal Resource, College of Agriculture, University of Salahaddin- Hawler, Kurdistan Region - Iraq

Present study was done to determent the genetic evaluations and effects of some nongenetic factors on post weaning performance and body dimensions of Awassi lambs in
Iraqi Kurdistan Region. A total of 86 lambs were used in this study post weaning weight,
gains and body dimensions until marketing age (6 month) were estimated on each lamb.
Data was subjected to analysis of variance to determine the effects of sex, horn, and
interaction between them on the growth and body dimensions of lambs. Sex, horn and
sex X horn significantly affected body weights and dimensions at all ages. Male and
horned lambs gave significantly higher weight and daily gain at different ages, as well as
the horned male and female gave higher weight and daily gain. Significant positive
correlations were found among body weight at different age, and all correlation among
weights with body dimensions at different ages were significant positive correlation
except the correlation among HG with body weight and dimensions at four month age.
The stepwise regression model were used to predict the body weight at 4 months of age
obtained for three out of eight dimensions with 61% R², but the best model to predict the
body weight at 5 months of age obtained for five dimensions with 87% R² and best one
for marketing age obtained from six dimensions with 88% R².
The effects of non-genetic factors necessary to be corrected before make the genetic
evaluations among animals, for it mixed model procedure ( Such as BLUP) are to be
used and BLUP values for lambs ranged from -11.902 to 10.697 kg for marketing
weight. These results indicated that there are high genetic variations among lambs for
this trait and it means that selection can play a big role in improving growth performance
in Awassi lambs.

Key Words: Genetic evaluation, Awassi lamb, Growth performance, BLUP Introduction 


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