Effectiveness*of*Equipment*to*Speed*Hay*Drying by#c.*alan*rotz,*agriculturalengineer USDA1ARS,PastureSystemsandWatershedManagementResearchUnit UniversityPark,PA16802 Highqualityforageisrecognizedasanimportantrequirementformaintainingmaximumproductionof cattle,particularlyindairyproduction.adequateroughageisneededindietstoprovidegoodrumen function,butasmoreroughageisfed,theenergydensityofthedietisreduced.highqualityforage allowstheanimaltoconsumeadequateforagewhileincreasingenergyintaketomaximizeproduction. Thegreatestobstacletoproducinghighqualityhayisrapidfieldcuring. Inourclimate,gooddryingconditionsareimportantanddifficulttoobtain.Adequateperiodswithout rainfallaresporadicandhardtopredict.althoughprocessesareavailabletospeedhaydrying,they mustbeusedalongwithgooddryingweathertobeeffective.newequipmentandprocesseshavebeen promotedtomakebetterhay,butfewhaveproventobeeffectivetools. Althoughhighqualityhayproductionisachallengeinourregion,therearepracticalstepsthatcanhelp. Usingtherightprocessattherighttimeisimportant.Conditioningandteddingtreatmentscanspeed drying,butsuchprocessesalsocauseloss.drymatterlossandnutritivechangesoccureachtimea machinepassesthroughthecropreducingthequalityofthefinalproduct.althoughsomelossis inevitable,goodmanagementcanreduceorcompensatefortheselossestoprovidethequalityforage needed.thebenefitsreceivedfromthesetreatmentsorprocessesmustbeweighedagainsttheadded coststodeterminethebestproceduresforhaymakingonyourfarm. Hay*Drying Theneedforrapidwiltingordryingofforagecropsinthefieldiswellrecognized,butaccomplishingthis taskremainsachallenge.manyfactorsaffectthefield1dryingrateofforage(rotz,1995).dryingis restrictedbythestructureoftheplant,swathstructure,andsoilandweatherconditions.themost restrictingfactorvariesthroughoutthedryingprocessandwithcropmanagement.whenahighyield cropislaidinanarrowswath,theswathtendstobemostlimitingbecausethemoisturecannotreadily moveoutoftheswath.whenforageisspreadinathinswath,themovementofmoistureoutofthe plantcanbecomelimiting.underthesecircumstances,conditioningofthecropismostbeneficialin allowingmoisturetoleavetheplantmoreeasily. Intemperateclimates,weatherisoftenthemostrestrictingfactorindrying.Ofallweatherinfluences, solarradiationlevelisthemostimportant(rotz,1995).thisenergyfromthesunisrequiredto evaporateandmovemoistureoutoftheplant.thedryingofhayrequirestheremovalofaboutthree tonsofmoistureforeverytonofhayproduced.thisrequires7billionjoulesofenergy,whichisthe
equivalentof70gallonsoffueloil.inhaymaking,wearefortunatethatfreeenergyfromthesuncanbe usedtocarryoutthisprocess.beskepticalwhenyouhearofnew,miraculousandinexpensiveprocesses thatcandryhaywithoutthesun.warmairtemperatureandlowhumidityalsoaidsdrying,butthesun istheprimarydrivingforce.wetsoilundertheswathalsoslowsdryingbyallowingmoisturetomoveup intotheswath. Drymatterlossesandqualitychangesoccurwhilethecropiswiltingordryinginthefield.Theseinclude plantrespiration,rain,andmachineinducedlosses.plantrespirationisanaturalprocessthatcontinues aftertheplantiscut.respirationconvertscarbohydratesstoredintheplanttissuetocarbondioxide, heat,andmoisturethatleavetheplantcausingadmloss.plantrespirationceaseswhenthecropdries toamoisturelevelbelow40%,sorapiddryingearlyinthefieldcuringprocesscanreducethisloss(rotz andmuck,1994).sincethislossisprimarilyreadilydigestiblecarbohydrates,thelossincreasesthefiber contentandreducestheenergycontentoftheforage.withrapiddrying,thislossislessthan5%,butit canbeexcessivewhendryingconditionsarepoor. Raindamage,whenitoccurs,canhavethegreatesteffectonlossandquality.Raincauseslossby knockingoffleavesandleachingsolublenutrientsfromwithintheplanttissue.sinceleavesarenormally higherinnutrientconcentrationsthanstemparts,thelossofleavesreducesthequalityoftheremaining forage.thegreaterlossthoughisthelessvisiblelossfromleaching.solublecarbohydrates,proteins, andmineralsarewashedfromtheplantmaterialleavingahigherfiberconcentrationandlowerenergy content.ingeneral,thegreatertheamountofrainandthedrierthecropatthetimeoftherain,the greaterthelossofdrymatterandnutrients.thegoalisalwaystoavoidraindamage,butwhenitoccurs, itisbettertohaveitearlyinthedryingprocessratherthanaboutthetimethecropisreadytobale.this issomewhatbeyondourcontrol,buttheproducercanbelessconcernedaboutrainthedayofmowing ifbetterweatherliesahead. Mowing*Equipment Producinghighqualityforagebeginswhenthecropismown.Foragecropsshouldbemownattheright maturitytooptimizeyieldandquality.qualityinmostforagecropsdeclinesratherrapidlyasthecrop entersareproductivestageofdevelopmentandgrowthbeginstoslow.theoptimummaturityvaries amongforagespecies,butnormallythisoptimumoccursinthelatevegetativetoearlyreproductive stages.mowingatthistimeprovidesagoodyield,arelativelylowfibercontentandadequateenergy andproteincontents. Achallengeinhayproductionistoobtainthisqualitylevelatatime1periodwhenweatherconditions aresuitablefordryingthecrop.whenheavyrainandpoordryingconditionsareexpected,itisnormally besttodelay.iftheforecastislightrainorabriefthunderstormwithadequatetogooddrying conditionsahead,itmaybebesttoproceedwithmowing.thelossinqualitymaybegreaterbydelaying harvestthenthatcausedbytherain. Thereareseveralmowerdesignsavailableforcuttingforagecropswiththeprimarytypesbeing cutterbarandrotarydiskmowers.thetypeofmowerusedhaslittleeffectondrying,mowinglossesand theresultingforagequality.rotarymowerstendtohaveahigherpowerrequirementandthusrequirea largertractorandmorefueltooperate.withahighermowingcapacity,though,lesstimeisrequired offsettingsomeoftheincreasedfueluseandreducingthelaborrequired.eventhoughthepurchase priceofrotarymowersisalittlehigherforagivenwidthofcut,theoverallcostofmowingissimilar betweenthesemajormowertypes.
* Conditioning*to*Speed*Drying Mechanicalconditioningtreatmentsareoftenusedtospeeddrying;thesecanbecategorizedaseither rollorflailconditioners.rollssmashand/orbreaktheplantstems,andflailsabradethewaxysurfaceof the plant and break stems. Both processes can improve drying, but for alfalfa, roll devices are more effectivewithlessfieldloss(rotz,1995).somerolldesignsarepromotedforfasterdrying,butfieldand laboratorystudiesconsistentlyshowlittleornodifferenceinthedryingofalfalfaorgrasstreatedwith commonlyusedcrushingrolldesigns.rollconditioningismosteffectiveonathickstemmedcropsuchas anearlycuttingofalfalfa.flailtypeconditionersarebettersuitedtograsscrops,andtheyprovidea greaterthroughputcapacitywhenharvestinghighyieldingorentangledcrops. Adjustmentoftheconditioningmechanismcanaffectdrying.Rollclearanceandpressureoftencanbe adjusted. A minimum clearance must be maintained. If the clearance becomes too close, excessive damageandlossofplantparticlesoccurs.withtoomuchclearance,plantmaterialflowsbetweenthe rollswithlittlecrushing.toolittleortoomuchpressureontherollshassimilareffects.onflailtype conditioners,theclearancebetweentherotatingflailsandastationarybarcanbeadjustedtocontrolthe amountofbreakingandabrasionthatoccurs. Drymatterlossesandtheassociatednutrientchangescausedorpromotedbyconditioningincreasewith cropmaturityandtheseverityofconditioning.althoughmoresevereconditioningcanprovidefasterfield curing,harvestlossesaregenerallygreater.normallymoderateconditioningisrecommendedtoobtain adequatedryingwithrelativelylowloss(112%ofyield).thisrelativelylowlosshaslittleeffectonforage quality. Considerableresearchanddevelopmenthasbeendevotedto intensiveconditioning overthepast20 years.severalmachinedesignshavebeenevaluated,whichshredtheplantmaterialtoallowmorerapid fieldcuring.dryingrateisincreasedby25to150%withthefastestdryinginthinwideswathsundergood dryingweather.powerrequirementisatleasttwicethatofamower1conditioner,andfieldlossescanbe veryhigh.toreducelosses,variousmethodshavebeenusedtopresstheshreddedmaterialintoamat. Whenrainoccurs,lossescanstillbeuptofourtimesgreaterthanregularconditioning.Duetoacomplex andexpensivemachinedesign,commercialapplicationhasnotoccurred. Achemicaltreatment,referredtoasaconditionerordryingagent,canbesprayedonalfalfaatmowing tohelpspeeddrying(rotz,1995).thechemicalaffectsthewaxysurfaceoftheplanttoalloweasier moisture removal. The most effective treatment found, is a potassium and sodium carbonate based solution. This treatment has only been effective on legume forage crops, and it is most effective on cuttingsharvestedinthesummermonths.chemicalconditioningworkswellwithmechanicalconditioning becauseitismosteffectiveonthecropswheremechanicalconditioningisleasteffective.thetreatment candoublethedryingrateofthecropwhenusedundergooddryingconditionswiththecropdriedina relativelythinswath.ontheaverage,thisincreasereducesfield1curingtimeabouthalfaday.fasterdrying reducesrespirationlossandoccasionallyavoidsraindamage.themajordeterrenttothisprocesshas beentheneedtohandlelargequantitiesoftheliquidtreatment(about30gallonsofsolutionperacre). * Swath*manipulation*to*speed*drying Asforagedriesinthefield,thetopoftheswathdriesmorerapidlythanthebottom.Manipulationofthe swathcanspeedthedryingprocessbymovingthewettermaterialtotheuppersurface(rotz,1995). Swath manipulation can also improve drying by spreading the hay over more of the field surface,
increasing exposure to the radiant solar energy and drying air. There are three operations used in haymakingtomanipulatetheswath:tedding,swathinversion,andraking. Teddingcanbeusedanytimeduringfieldcuring,butitisbesttodosobeforethecropistoodry(above 40%moisturecontent).Thestirringorfluffingofforagetypicallyreducesfield1curingtimeuptohalfa day.teddersaresometimesusedtospreadanarrowswathformedbythemower1conditioneroverthe entirefieldsurface.whendonesoonaftermowing,theaveragefieldcuringtimeisreducedupto2days comparedtodryinginanarrowswath.inadditiontospeedingdrying,teddingalsotendstocreatemore uniformdrying,sowetspotsintheswatharereduced. Disadvantagesofteddingincludeincreasedlossesandincreasedfuel,labor,andmachinerycosts.When teddingisdoneonarelativelywetcrop(above50%moisture),theresultinglossislessthan3%;however, appliedlateinthedryingprocess,thelosscanbemorethan10%.teddingwillalsoincreaserakingloss. Whenalightcrop(lessthan1ton/acre)isspreadoverthefieldsurface,rakinglosscanbemorethan doublethatwhenrakingnarrowswaths.spreadingthehaymaypromotebleachingofhaycolor.bleaching doesnotnecessarilyaffectthenutritivevalueofhay,butitoftenaffectsthemarketvalue.whenthecosts of performing the tedding operation are compared to the benefit received, routine use of tedding is difficulttojustify,particularlyforalfalfa.occasionaluseunderdifficultdryingconditionsmaybringgreater economicbenefit. Swath inversion machines have been used that gently lift and invert the swath. Exposing the wetter bottomoftheswathspeedsdrying,reducingtheaveragefield1curingtimeafewhours.swathinversion isnotaseffectiveforimprovingdryingastedding,butshatterlossisverylow.withlessdryingbenefit, thereislesspotentialforreducingrainandrespirationlosses.theaddedlabor,fuelandmachinerycosts oftheoperationaregenerallygreaterthanthebenefitreceived. Rakingisanotherformofswathmanipulation.Rakingtendstorollthewetterhayfromthebottomofthe swathtotheoutersurfaceofthewindrow,whichimprovesdrying.followingtheinitialimprovement,the increaseinswathdensitycanreducedryingrate,sothecropmoisturecontentatrakingisimportant. Rakingalsocausesloss,andthelossisrelatedtocropmoisture(2%whenwetto15%inverydrycrop). Thebestmoisturecontenttorakeforlowlossandgooddryingisbetween30and40%.Indryweather periods,haycanberakedintheeveningorearlymorningwhenleavesaremoistandlesspronetoshatter. Rakingatthepropertimecanreducefield1curingtimeafewhourstoallowanearlierstartatbaling. Inhaymaking,thebestrecommendationistodryhayrapidly.Mechanicalconditioningshouldbeused, andhighyieldingcropsshouldbespreadinwideswaths.teddingmaybeusefulindryinggrasscrops,but itshouldbeavoidedwithalfalfa,particularlyafterthecrophaspartiallydried.insilagemaking,dryingis alittlelesscritical.wiltinginnarrowswathscanreducerakingloss,particularlyforlowyieldingharvests. Rakingcanbeusedtoimproveharvestcapacity.Asubstantialeconomicbenefitcanoftenbeobtainedby rollingswathstogethertoallowlargebalersorforageharvesterstooperatemoreefficiently. Baling*High*Moisture*Hay Anotheroptionforshorteningthefieldcuringtimeistobalehaybeforeitisfullydry.Balersareavailable whichproducebalesofawidevarietyofshapesandsizesandthesafemoisturecontentforhaystorage varieswithsize.balingattheappropriatemoisturecontentisimportantforminimizingharvestlossand maintainingqualityfollowingharvest.forlow1density(smallrectangularandmostlargeround)bales,the recommendedbalingmoisturecontentisabout18%.forhigh1densitybales(largerectangular),drierhay
intherangeof12to14%isrecommendedtoimprovepreservation.harvestlossincreaseswhenhayis baledatlowermoisturecontents. Respirationofmicroorganisms(bacteria,fungi,andyeasts)onhaycausesheatingandfurtherDMand nutrientlossduringstorage.similarlossoccursinallsizesandtypesofbalesstoredinashed(rotzand Muck,1994).Greaterheatingoccursashaydensityincreases,particularlyinlargebales.Drymatterloss during the first month of storage varies from 1 to 8% increasing with hay moisture content. For hay containing more than 25% moisture, excessive loss and even spontaneous combustion can occur. Althoughmostlossoccursinthefirstmonth,asmalllossofabout0.5%DMpermonthcontinuesinhay storedinashed.unprotectedhaystoredoutsideexperiencesthissamelossplusanadditionallossfrom weatheringontheexposedbalesurface(outer10to20cm).lossesinlargeroundbalesstoredoutside varywidely,rangingfrom3to40%.thislossisprimarilyaffectedbyweather,lengthofstorage,and storagemethod. Fieldlossescanbereducedbybalingatamoisturecontentnear25%.Balingmoisthaymayreduceraking andbalinglossesprovidinganincreaseinharvestedyield(about7%)andharvestedquality.however, moisthaydeterioratesrapidlyinstorage,offsettingthebenefitofreducedfieldlossesunlesstreatedto enhance preservation. Additives commonly used for the preservation of high1moisture hay include propionicacid,organicacidmixtures,bufferedacidmixtures,andmicrobialinoculants. Propionicacid(oraneffectiveorganicacidmixture)whenappliedatratesof1to2%ofhayweight, normallyreducesmoldgrowthandheating.toreducecorrosionofequipment,bufferedacidproducts havelargelyreplacedthestraightacids.acidtreatmentreducesstoragelossduringthefirstfewmonths ofstorage,butthelossremainshigherthanthatindryhay.acid1treatedhayremainsmoisterthroughout storagemaintainingalittlehigherlevelofmicrobialactivity.overa61monthstorageperiod,thelossin acid1treatedhaycatchesup,providinglittledifferenceindrymatterandnutrientlossesbetweentreated anduntreatedhigh1moisturehays.whencomparedtodryhay,acid1treateddamphayisoftenhigherin fibercontentandlessgreenincolor.treatedhaywillcontainmoremoistureincreasingbaleweightand providingmoresupplehay. Bacterialinoculantsaresometimesappliedtohay.InoculationwithafewstrainsofLactobacillushave shownlittleeffectonmold,color,heating,dmloss,andqualitychangeinhigh1moisturehay.products containing Bacillus bacteria are better suited to the aerobic hay environment, but there is still little scientificevidencethattheycanprovidesubstantialimprovementinpreservingmoisthay. Based upon the scientific information available on chemical and biological treatments, my recommendationistobaledryhaywheneverpossible.whenmoisthayisbaled,organicacidtreatments canprovidearelativelysafemethodforinsuringagainstexcessiveheatingandbrowningofhay. Feeding*Considerations Forthecommercialhayproducer,highqualityhayisimportanteverytimehayismade.Whenhay qualitysuffersforanyoftheabovereasons,theeconomicvalueofthehaydecreasesandthisaffects farmprofit.thus,commercialhayproductionrequiresgoodmanagementalways,andtechniquesfor assuringqualitymaybemorecosteffectivethantheywouldbeforthelivestockproducer. Whenhayisproducedforon1farmuseinfeedingbeefcattleandevendairycattle,foragequalitycanbe lessimportant.thisassumesthoughthatgoodmanagementisusedtofeedthehighestqualityforageto
theanimalsthatrequirethatquality.fordairyanimalsinearlylactation,thehighestqualityforageis neededtomaximizetheirintake.maximizingintakeduringthiscrucialstagewillallowanimalstopeak theirproductionatahighlevel.thus,thevalueofforagequalitycannotbeoverestimatedforthese animals.forotheranimals,includingthoseinthelasthalfoftheirlactation,earlydrycowsandyearling heifers,foragequalityislesscritical. Thus,producersthatarefeedinganimalsmustfocusonproducingorbuyingthebestforagetheycan obtainfortheircriticalgroupswhilereservinglowerqualityforageforotheranimals.thismeansthat onlyone1fourthtoone1thirdofthetotalforageneededondairyfarmsmustbeofthishighestquality.in beefoperations,therequirementforhighqualityforageisevenless.forthedairyproducerthatkeeps thisinmind,producinghighqualityforagewillbealessstressfulprocess.concentrateonmakingsome ofthebestforageyoucanandfeedingitappropriately,anddonotworryaboutthetimesyoufail.some lowerqualityforagecanalsobeusedquiteeffectivelyonthefarm. Conclusions Rapidfieldcuringisimportantandagoodmechanicalconditionercanhelp.Spreadhayinwideswathsto furtherspeeddrying,butavoidverythinswathstoreducerakingloss. Teddingmaybeusefulindryinggrasscrops,butitshouldbeavoidedwithalfalfa,particularlyafterthe crophaspartiallydried. Balehayatabout18%moistureinlow1densitybales,butusealowermoisturecontentforhigh1density largebales. Avoidroutinebalingofhighmoisturehay.Whendamphayisbaled,useanorganicacidbasedtreatment tohelppreservehay. Rememberthatonthedairyfarm,onlyaboutonethirdoftheforageneedstobeofthehighestquality whenthatforageissegregatedbyqualityandfedtoanimalgroupsaccordingly. References Rotz,C.A.andR.E.Muck.1994.ChangesinForageQualityduringHarvestandStorage.In:ForageQuality, Evaluation,andUtilization,Eds.G.C.Fahey,Jr.etal.Am.Soc.Agron.,Madison,WI.pp.8281868. Rotz,C.A.1995.FieldCuringofForages.In:Post1HarvestPhysiologyandPreservationofForages.CSSA SpecialPublicationno.22.CropSci.Soc.Agron.andAm.Soc.Agron.,Madison,WI.pp.39165.