Genetic and economic analysis of introgression the B allele of the FecB (Booroola) gene into the Awassi and Assaf dairy breeds

Selection for yield and the adoption of an intensive management system unde rpins the high milk production of the Improved Awassi and the Assaf dairy f locks in Israel. However, lamb production, which contributes some 40% of th e income, remains relatively low at 1.2 and 1.6 lambs born/ewe lambing (LB/ EL) for the Awassi and the Assaf, respectively. To increase the profitabili ty, through improved lamb production, a breeding scheme was initiated in 19 86 to introduce the B allele of the FecB (Booroola) gene to the Awassi and Assaf breeds. This led to the formation of the Afec-Awassi and Afec-Assaf s trains with prolificacy of about 2.0 LB/EL, A marker assisted selection app roach and the use of induced ovulation rate as selection criteria were inco rporated into the breeding programs. The Awassi is the main type of sheep i n the Middle East where about 80 million sheep of this breed and other rela ted fat tail breeds are present. Distribution of the BB Afec semen or rams in those flocks, through regional breeding programs, can improve their prod uctivity and their economics, facilitating the transition into a more inten sive production system. The economic justification for launching such a bre eding program depends mainly on the local lamb price. (C) 2001 Elsevier Sci ence B.V. All rights reserved.