الفهرس 
INTRODUCTION
Non - genetic factors affecting growth performance of lambsOnly 14 pages are availabe for public view
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Abstract
sUmaRY
A total of 5242 Ossimi and 6244 Rabmani records were used for the study. Data were collected auring the year. 1970—1984 on six sheep flocks, raised under accelerated larabing system.
Lambs body weight was measured at birth (Wç) and 2(W2), 3 (143), 4 (Ic4), 6 (W), 8 (148), 10 (W10), 12 (W12) and 18
(WIG) ‘no. A simple linear regression equation was fitted for each animal from blrtt to 120 a iiile, a multiple regression equation (quadratic) was fitted to describe growth curve from birth to the age of 18 mo.
Iamb’s weights (W0—W13) and growth parameters ($.
and $2) were analyzed for each breed separately using mixed model to estimate variance and covariancé components for the random effect of sire within faz,l and fixed effects of farm, block, season, type of birth and age of dam a1or” with the interactions between block ana season, block a.... type of birth, block and age of dam, season and sex, seasoni and type of birth, season and age of dam and sex and type
birth.
All main effects were generally significant (p< 05)
explaining the variation of lamb body weights and growth parameters. All interactions showed an effect (p<.05) on
studied traits.
Average of W0, W2, W3, W4, W6, W9, W10, W12 and W18
3.03, 12.70, 15.50, 18.71, 24.56, 28.46, 31.29, 36.03
42.69 kg in Ossimi and 3.12, 12.80, 15.60, 18.00, 23.73,
28.56, 32.78, 37.41 and 44.60 kg in Rahmani, respectively.
Degree of maturity was 5.70, 24.00, 30.00, 36.00, 47.00,
55.00. 61.20, 69.10 and 31.8, in Ossimi and 5.11, 20.98,
25.51, 29.40, 38.77, 46.67, 53.57, 61.12 and 72.68
birth, 2, 3, 4, 6, 8, 10, 12 and 18 ma, respectively.
Estimates of mature weight obtained for Ossimi
Rahmani were 52.13 and 61.19 in the two breeds, respectively.
Heritability estimates for W0, W2, W3, W4, W6, W8, W10,
and W10 were .99 ,.28,.49,.57,.61,.59,.83,. 87
.11 arid .82 ,.83,.68,.54,.52,.31,.36,. 45 and .33.
Genetic correlations were positive (P<.Ol) and ranged from .28 to .98 in Ossimi and from .33 to .92 in Rahxnani between body weights
In conclusion, the second order regression model
appropriate in fitting growth data in Ossini and Rahmani sheep from birth to 18 no. Heritabilities of lamb
weights and growth parameters were generally high indicating the effectiveness of genetic selection for improving
studied traits beside the possibility of changing
pattern of lamb growth curves genetically for higher productions.