title: Prolificacy and lamb survival at birth in Awassi and Assaf sheep carrying the FecB (Booroola) mutation.
abstract: Prolificacy up to the fifth parity and lamb survival at birth were investigated in >or=31/32 Awassi and >or=31/32 Assaf sheep belonging to the ++, B+ and BB genotypes at the FecB locus. In the Awassi, prolificacy of ++, B+ and BB ewes was 1.28, 1.90 and 1.92 lambs born/lambing (LB/L), respectively. In the Assaf, prolificacy of ++, B+ and BB ewes was 1.68, 2.40 and 2.55LB/L, respectively. Lamb survival at birth in the ++ Awassi and the ++ Assaf averaged 0.98 and 0.94, respectively. It declined to 0.93 and 0.86, and 0.85 and 0.78 in the B+ and BB Awassi and B+ and BB Assaf, respectively. For singles, twins, triplets, quadruplets and quintuplets, lamb survival rate at birth was 0.98, 0.92, 0.86, 0.78 and 0.65, respectively. FecB genotype-litter size interactions were not significant (P<0.05). A compilation of study results in which prolificacy of the ++ and B+ genotypes at the FecB locus were investigated in a range of breed-environment combinations revealed that the B allele has a multiplicative effect on prolificacy as B+ prolificacy was significantly (P<0.05) linearly associated with ++ prolificacy.
authors.affiliation: Institute of Animal Science, ARO, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel. gootwine@agri.gov.il
authors.forename: Elisha
authors.initials: E
authors.lastname: Gootwine
authors.forename: Shay
authors.initials: S
authors.lastname: Reicher
authors.forename: Alexander
authors.initials: A
authors.lastname: Rozov
mesh_terms: D000483:Alleles; D000818:Animals; D000831:Animals, Newborn; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000235:genetics*; D003433:Crosses, Genetic; D004247:DNA / Q000737:chemistry / Q000235:genetics; D005260:Female; D005838:Genotype; D016018:Least-Squares Analysis; D008098:Litter Size; D008297:Male; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D012756:Sheep / Q000235:genetics*; D016019:Survival Analysis
chemical_list: D004247:DNA; D052005:Bone Morphogenetic Protein Receptors, Type I