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 underpins the high milk production of the Improved Awassi and the Assaf dairy flocks in Israel. However, lamb production, which contributes some 40% of the 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 profitability, through improved lamb production, a breeding scheme was initiated in 1986 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 strains with prolificacy of about 2.0 LB/EL. A marker assisted selection approach and the use of induced ovulation rate as selection criteria were incorporated into the breeding programs. The Awassi is the main type of sheep in the Middle East where about 80 million sheep of this breed and other related fat tail breeds are present. Distribution of the BB Afec semen or rams in those flocks, through regional breeding programs, can improve their productivity and their economics, facilitating the transition into a more intensive production system. The economic justification for launching such a breeding program depends mainly on the local lamb price.