Crossbreeding components in age at first egg and egg production for crossing Saudi chickens with White Leghorn

摘要

Two-generationsofcrossbreedingexperimentinvolvingBaladiSaudi(S)andWhiteLeghorn(L)chickenswereevaluatedforageatfirstegg(AFE),firstthree-montheggproduction(EP3)andannualeggproduction(AEP).SixgeneticgroupsofLxL,SxS,LxS,SxL,LxSLandSxLSwereproducedinthisexperiment(twopures,twoF1crossesandtwobackcrosses).VariancecomponentsandheritabilitiesfortheseeggtraitswereestimatedusingDFREMLprocedureofmulti-traitanimalmodel.ThegeneticmodelofDickersonwasusedtoestimatethegeneticcomponentsofthisexperimentintermsofdirect(GI)andmaternal(GM)additiveeffects,direct(HI)andmaternal(HM)heterosis,anddirectrecombinationloss(RI).BackcrossofLx#190;L#188;Srecordedhighereggproductionthanothercrossbredgroups.HeritabilitiesforAFE,EP3andAEPwere0.55,0.31and0.54,respectively.Directadditiveeffects(GI)forAFE,EP3andAEPwereconsiderableandinfavouroftheLbreed.L-siredhenshadhighGIcomparedtotheS-siredhensforthetraits.Formaternaladditiveeffects(GM),areversibletrendwasrecordedinfavourofSbreed.CrossbredhensrecordedpositiveestimateofHIforAEPandnegativeestimateforAFE.TheestimatesofHIwere-2.7%forAFEand2.7%forAEP.EstimatesofHMindaughtersofcrossbreddamsforEP3andAEPwerepositive,whiletheestimateforAFEwasnegativeandfavourable.TheestimatesofHMwere-16.4%forAFE,19.1%forEP3and12.3%forAEP.EstimatesofRIincrossbredhensforAFE,EP3andAEPwere1.6days,-11.9eggand-28.3egg,respectively;RIforageatfirsteggwaslimited,whilethetwoestimatesforeggproductionwerehigh.