Genetic trends for ewe traits in two flocks fo Rahmani and Ossimi sheep
Abstract: This study was carried out on a total of 11150 Rahmani and 9226 Ossimi ewe records progeny of 357 and 226 sires, respectively, during the period from 1959 to 1999 to estimate genetic trends in ewe traits. Mixed model methodology based on a multi-trait animal model was used. Data were classified and analyzed in two periods according to the management system. Animals in the first period (1959 -1970) had one breeding cycle per year while in the other period (1970-1999) they had a breeding cycle every eight months. Estimated annual genetic change, based on predicted breeding values, for ewes conceived/ewes joined. Iambs born/ewe lambed, lambs weaned/ewe lambed and kilograms born/ewe lambed for the first period was -.000098. -.000488. -.000509 and -.003055, respectively in Rahmani. and -.000472. .000678. .000462 and .008425 in Ossimi and in the second period the change was -.000118. -.000200. -.000044 and -.000555 in Rahmani. -.000131, -.000544, -.000662, and -.000156 in Ossimi, respectively. All these trends were statistically non significant except for those lambs born per ewe lambed and lambs weaned per ewe lambed for Ossimi in the second period.
Generally, the study indicated lack of effective directional selection in those flocks
Keywords: Selection, Conception, Litter size, , ,Heritability, Genetic correlations
Publication year 2004
Pages 43-54
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى- الجيزة
Availability number
Organization Name
serial title Egyptian Journal Animal Production
Author(s) from ARC
External authors (outside ARC)
    صلاح جلال جامعة عين شمس
Agris Categories Animal husbandry
AGROVOC
TERMS		 Ewes. Heritability. Litter size. Reproductive performance. Selection. Sheep.
Proposed Agrovoc Genetic correlations;
Publication Type Journal
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