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1、奶牛营养需要!(精)DS381. ThisdocumentisDS38,oneofaseriesoftheAnimalScienceDepartment,FloridaCooperativeExtensionService,InstituteofFoodandAgriculturalSciences,UniversityofFlorida.OriginalpublicationdateJuly,1992.ReviewedJune,2003.VisittheEDISWebSiteathttp:/edis.ifas.ufl.edu.2.Professor,DairyScienceDept.;Coo
2、perativeExtensionService,InstituteofFoodandAgriculturalSciences,UniversityofFlorida,Gainesville.TheInstituteofFoodandAgriculturalSciences(IFASisanEqualEmploymentOpportunity-AffirmativeActionEmployerauthorizedtoprovideresearch,educationalinformationandotherservicesonlytoindividualsandinstitutionsthat
3、functionwithoutregardtorace,creed,color,religion,age,disability,sex,sexualorientation,maritalstatus,nationalorigin,politicalopinionsoraffiliations.Forinformationonobtainingotherextensionpublications,contactyourcountyCooperativeExtensionServiceoffice.Florida/CooperativeExtensionService/InstituteofFoo
4、dandAgriculturalSciences/UniversityofFlorida/LarryR.Arrington,InterimDeanProperfeedingandgoodbalancedrationsremainthecornerstoneofasuccessfuldairyoperation.Milkyieldpercowandthecostoffeedtoproducemilkhavebyfarthegreatestinfluenceonprofitabilityinadairyoperation.Ifadairyistobesuccessful,thedairymenmu
5、stcontinuallystrivetoadoptpracticesthatallowthegreatestoutputofmilkatthemosteconomicalcost.Successfuldairyinginthefuturewilldependonhighlevelsofmilkproduction,cullingforlowproduction,controllingfeedcosts,andusinggoodreplacements.Cowidentificationandgoodrecordsmakegoodfeedingpracticespossible.Without
6、milkproductionrecords,itisdifficulttofeedaccordingtomilkproductionortouseanywell-designedgroupfeedingsystem.MilkyieldspercowcontinuetoincreaseannuallyasreportedbytheUSDANationalAgriculturalStatisticsService.AverageproductionpercowintheUnitedStatesreportedin1975was10,360lbsascomparedto14,213lbsin1988
7、.Muchofthisincreaseinmilkproductionisduetobetternutritionandfeeding,overallmanagementpracticesandthegeneticimprovementofthecowpopulation.FEEDINGSTANDARDSFeedingstandardshavebeenusedsincethelate1800stohelpguidenutritionistsandlivestockproducersinformulatingrationsandfeedinglivestock.Periodically,thes
8、tandardsareupdatedtoencompassthemostcurrentresearchinformationavailable.Thestandardsthatarenowavailable,entitledNutrientRequirementsofDairyCattle,wereupdatedin1988byasubcommitteeonDairyCattleNutritionoftheNationalResearchCouncil.Table1,Table2andTable3showthenutrientrequirementsofdairycattleasdevelop
9、edbytheNationalResearchCouncil(1988.FiguresTheenergyrequirementsusedfromthispublicationareexpressedasnetenergyformaintenance(NEM,netenergyforlactation(NELandtotaldigestiblenutrients(TDN.EventhoughbothTDNandNELareacceptablemeasuresofenergy,NELisexpressedasmegacalories(McalwhereasTDNisgiveninpounds.Th
10、eNELisdefinedastheenergycontainedinthemilkproduced.Sincemilkfatishighinenergy,cowsproducingahigherfattestingmilkrequiremoreenergyperpoundofmilk(Table2.ProteinAsmilkproductionincreases,itbecomesimportantthatsomedietaryproteinescapedegradationinrumenfermentation.Proteinthatbypassestherumenisdegradedto
11、aminoacidsandabsorbedfromthesmallintestineforutilization.Theseessentialaminoacidsareneededbythehighproducingcowandmustcomeeitherfromdietaryproteinthatescapesdegradationormicrobialproteinproducedduringrumenfermentationandpassedalongtothesmallintestine.The1988NutrientRequirementsofDairyCattlediscussed
12、forthefirsttimebothabsorbedandcrudeprotein.Thedietaryintakeproteinisdescribedasundegradableintakeprotein(UIPanddegradableintakeprotein(DIP.AlthoughaspecificpercentUIPisnotstated,thecalculationssuggest35to40%bypassprotein.Processingorheattreatmentoffeedstuffsincreasestheamountofbypassproteininthefeed
13、stuff.Commonlyusedbypassproteinsupplementsaredistillersgrains,brewersgrains,cornglutenmeal,bloodmeal,meatandbonemeal,feathermealandheattreatedsoybeans(Table4.Forfasterusageandconvenience,Table3hasbeendevelopedtocontainthecombinedrequirementsformaintenanceandmilkproductionfordifferentsizeddairycowspr
14、oducingmilkcontaining3.5%fat.ThecompiledinformationinTable3willsavetimeincalculatingrequirements.FEEDSANDTHEIRCOMPOSITIONTable4containsalistofthemorecommonfeedingredientsusedinFlorida.Valuesgivenoningredientsaredrymatter(DM;crudeprotein(CP;bypassprotein(BP;totaldigestiblenutrients(TDN;netenergyforla
15、ctation(NEL;fat,calcium(Ca;phosphorus(Phos;sodium(Na;magnesium(Mg;potassium(K;andsulfur(S.TheTDNandNELreferstotheenergycontentofthefeed;eithermaybeusedinformulatingrations.Table5showsthemineralcompositionoffeedscommonlyusedindairycattlerations(U.S.Fed.FORMULATINGDAIRYRATIONSRationsarenutritionallybalancedandformulatedtomeetthenutrientrequirementsofanimalsperformingatdifferentlevels.Thenutrientrequirementsformaintenanceandmilkproductionfordifferentsizedanimalsincludingenergy
