Utilisation des fruits de Faidherbia albida pour l'alimentation des bovins d'embouche paysanne dans le bassin arachidier au Sénégal

摘要

Feedisthemajorconstraintthatlimitsthepotentialofthegroundnut-growingregionofSenegaltocontributetothenation'sneedformeat.Theproblemisattwolevels:highqualityconcentratesarenotavailableatanacceptablepriceandthetechnicalskillsofthelivestockproducersareratherweak.Thetendencyistogiveadiethighinconcentratesandnottocontroltheamountthatisgiven.Theuseofproductsobtainedfromlocalnaturalresourcesintheareaisanalternativethatcouldhelptoovercomethefeedconstraints.Inordertopromotetechnologiesthatwouldfacilitatethegreaterintegrationofnaturalresourcesintheproductionsystemtwoexperimentshavebeencarriedout;oneinourresearchlaboratoryandtheotherincooperationwithfarmersintheBambeyregionsituatedinthenorthofthegroundnut-growingarea.Theaimoftheexperimentswastoevaluatetheuseofthefruitsofthelegumetree,Faidherbiaalbida,asacomponentofthedietforfatteningcattle.TheinvivodigestibilityofthedrymatterofthefruitsofF.albidawasdoneusingfourlevelsofsubstitutionofthefruitsandanalysisbyregression.Thefeedingtrialwaswithyoungbullsfedfor52daysonfarmsinthreevillagesintheBambeyregion.Thedietbythefarmerscontained(%DMbasis):choppedsorghumstalks(26),sorghumbran(32),molassed-wheatbran(21)andF.albidafruits(21).Theresultsshowedanon-linearresponseindietdigestibilityaccordingtolevelofinclusionoftheF.albidafruits.Therewasanindicationthattotaldigestibility(Y=%)increasedasthelevelofthefruits(X=%)intherationDMincreased.Theequation(Y=48.6-0.0123X+0.00064X*X;R2=0.68)predictsaDMdigestibilityofthefruitsof53.8%atthetheoretical100%inclusionlevel.Intheon-farmtrials,themeanvalues(forthethreesitesrespectively)offeedintake,dailyweightgainandprofit(as%ofinvestment),were134,123and124g/kgW0.75;1,100,615and173g/day;and2,13and0%.Therewasasignificantdifference(P0.01)ingrowthratesbetweensitesprobablyreflectingtheskillsoftheindividualfarmerincattlefattening.ThehighratesofliveweightgainontwoofthefarmsindicatethatthefruitsofFaidherbiaalbidahavepotentialasanalternativefeedresourceinrationsforfatteningcattleatlowercostcomparedwithuseofexcessivelevelsofconcentrates.AlthoughdigestibilitywasnotdepressedbyhighlevelsofF.albida(infactthetendencywasforanincrease),itisprovisionallyrecommendedtolimittheinclusionlevelto20%ofdietdrymatterinviewofthehighcontentofcondensedtanninsinthefruitandtheknownnegativeeffectoftheseonanimalperformancewhenpresentathighlevelsintheration.