Analysis of factors effecting milk yield and composition in Sicilo-Sarde ewes, in the region of Beja (Tunisia)

摘要

ThisinvestigationwascarriedouttostudythemilkyieldandtocharacterizeitscompositionandthemainvariationfactorsinSicilo-SardeewesfromtheregionofBéja(NorthofTunisia,Sub-humid).Simultaneously,ewesfeedingsystemsintheregionwerecharacterized.Thestudyconcerned804ewesfromfivefarmsduringtheseason2005-2006.Forallthestudiedfarms,feedingwasbasedonoatsilage,commercialconcentrateandgrazing(M1:twofarms),plushayorstraw(M2:2farms)andalsowheatbran(M3:onefarm).Totalmilkyieldduringthemilkingperiodwasabout85L,withadailyproductionof0,5L.Milkcompositionduringthesameperiodwascharacterizedaveraged75and63.5g/Kgrespectivelyforfatandprotein.ThefeedingsystemM3seemedtoinducethehighest(P0.01)milkproduction(100,2L/ewe)comparativelywiththetowotherswhichweresimilar(80L/ewe).nbsp;Byanotherhand,thefeedingsystem(M1)gavethehighest(P0.01)contentoffat(77.4g/Kg).While,M2resultedinthehighest(P0.01)rateofproteinnbsp;(67.6g/Kg).nbsp;Resultsindicatedthatthelactationrowaffectedmilkproductionandcomposition(P0.05).Indeed,totalmilkyielddecreasedwitheweage(P0.05).Fatandproteinratesreachedthemaximumvaluesatthethirdlactation(P0.05).The60days-sucklingtyperesultedinthehighestmilkproduction(P0.01).While,nbsp;the75days-sucklingtypeinducedthehighestratesoffatandprotein(respectively,P0.05andP0.01).Themodalityofweaninghadnosignificanteffectonmilkyieldmilkproteinrate,butseamedtoeffectfatcontent(P0.01).