الفهرس 
material and methodOnly 14 pages are availabe for public view
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Abstract
This study was carried out by the cooperation between the Animal Production Research Institute and animal production department faculty of agriculture, Mansoura University. Data used in the present study were collected during the period from 1988 to 2001.Romanov flock was raised in Mahallet-Mousa station (Mid Delta). The main objectives of this study (1) to investigate the effects of year of birth, sex and type of birth on production traits [weight at birth (BW), weight at one month of age (W1), weight at two months of age (W2), weaning weight at three months of age (W3) and average daily gain from birth to weaning (ADG)], (2) estimated phenotypic and genetic parameter affecting on birth weight, body weight at one month, body weigh at two months, body weight at three months (weaning weight), and average daily gain from birth to weaning. (3) Estimated predicted breeding values for traits above by using multi-trait Animal model (MTDFREML) in Romanov sheep. Genetic progress is possible for all growth traits analyzed for the Romanov lambs; however, inclusion these traits in any selection program would need to take into account the heritability and genetic correlation among growth trait especially between average daily gain and weaning weight with other traits. Moderate heritability estimates for all growth traits indicated that, improving programs for these trait must be included improving environmental conditions with genetic improvement to achieved results preferable. The higher range of lamb breeding values for all traits concluded that, selection of lambs for the next generation would lead to higher genetic progress in this herd.