Grass Programme Sec 5

7/29/2019 Grass Programme Sec 5

1/19

5:1Improvement through grassland management

5 Managing your grazing

Whats inthis section? Preparing or grazing

Deciding the length o the rotation

Planning or critical times osward availability

Calculating the number o eedsrom a feld

Calculating the actualorage supplied.

Objective: Tocaterforrapidchangesinswardqualityand

quantitywithaexiblegrazingapproach.

Challenge: Walkandassessswardsatleastonceaweek

Achievea10%increaseindaysof

consistentqualitypasturesupplythis

year,togetherwitha0.5tonne/cow

increaseinutilisedpastureDMintake.

Target

Increasepastureintakeby1.0tonneutilisedDM/cow.

Every Day Good Grazing

Planningaexibleapproachtoensurethe

consistentsupplyofqualityforagerequired

throughoutthegrazingseasonisonething.

Actuallymaintainingitinthefaceofrapidly

changingswardgrowthrates,pasturequality

andcowrequirementsissomethingelse.

Despitetheverybestofintentions,agoodqualityspringswardalltoooftenbecomesprogressivelyless

productiveastheseasonprogressesandtherealities

ofday-to-daymanagementpressurestaketheirtoll.

Closemonitoringofprogressthroughthegrass-

growingseasonisthekeytocopingwiththe

unpredictabilitythatcanbeassociatedwith

grazing.Italsoprovidesmuch-neededcondence

toachievemorefromgrazedgrass.

ContentsTurnoutManagement Page5:3

RotationLength Page5:9

ShortfallsandSurpluses Page5:12

FeedsperField Page5:15

PastureUtilisation Page5:16

Adjusting the grazing rotationlength is essential to keep on topo swards that can grow twiceas ast one month as the next.

5Managing

yourg

razing


2/19

5:2 Improvement through grassland management

Action planTo increase your pasture intake by 1.0 tonne utilised DM/cow.

1. Preparing or Turnout

Makesureyourpasturesandcowsare

readyforturnoutandmanagethewhole

processcarefully(Page 5:5).

2. Maintain the Best Rotation Length

Useeldcoverstoensureyourpasture

rotationlengthmatchesgrassgrowth

throughouttheseason(Page 5:9).

3. Identiy Costly PastureImbalances Early

Assessyoureldcoveravailabilityor

pasturebalancescontinuallytoidentify

costlypotentialgrazingsurplusesorshortfallsaheadoftime(Page 5:12).

4. Address SwardSurpluses Eectively

Takeeffectiveimmediateandlonger-term

actionassoonasyourgrasslookslikebeing

surplustograzingrequirements(Page 5:13).

5. Address SwardShortalls Eectively

Takeeffectiveimmediateandlonger-term

actionassoonasyourgrasslookslikebeing

inshortsupplyforgrazing(Page 5:14).

6. Calculate Feeds per Field

Assesseacheldforthenumberoffeedsitwill

providetoensurethemosteffectivemanagement

(Page 5:15).

7. Measure Sward Utilisation

CompareactualswardDMintaketothecoveryou

allocatetomonitorutilisationefciency(Page 5:16).


3/195:3Improvement through grassland management

Turnout management

Atturnout,milkproductionlevelsmayriseorfall

forafewdays.Thisisonlytobeexpectedas

cowsadjusttothesubstantialchangeinvolved

inswitchingsuchamajorpartoftheirDM

intakefromconservedtofreshforage.

Itisimportanttohavethecondencetostickwiththe

grazingstrategy,evenifmilkproductiontemporarily

fallssharply.

Providedadequategrazingisavailableanyeffect

onmilkoutputwillbetransientandproduction

willreturntopreviouslevelsinafewdays.

Agradualtransitiontograzingover2-3weeksor

longer,withgrazingintakesstartingat4-5kgDM/

cow/day,minimisestheseeffectsbyenablingthe

rumenmicrobestoacclimatisetothechangeindiet.

Cowsshouldbeabletograze5kgofdry

matterinthreehoursquiteeasily.

Insomecircumstances,thegroundmaybea

littletender/softinearlyspring,soalower

stockingratewillmeanlessfeetandtimeon

anyparticularareaand,therefore,lesschance

ofdamageandpoachingofthesward.This

isbestshowninthefollowingexamples:

Example calculations or spring grazing

Case 1. Grazingcoveris2800kgDM/haandtherequiredresidualis1500kgDM/ha.Soevery

hectareofgrazinghas1300kgDMtograze.

Aherdof100cowsrequiring5kgDM/

headadayofgrazingmeansthetotal

demandis500kgDMaday.

Therequired500kgdemanddividedby1300kg

supply,willbeprovidedby0.38haaday.

Case 2. Grazingcoveris2400kgDM/haandtherequiredresidualis1500kg

DM/ha.Soeveryhectareofgrazinghas

apotential900kgDMtograze.

Aherdof100cowswithadailydemandof5kg

DM/headmeansthetotaldemandis500kgDM.

Therequired500kgdemand,dividedby900kg

supply,willbeprovidedby0.55haaday.

InCase2,cowswillbespreadoveralarger

area,reducingthepotentialtocausesoildamage

bypoaching.

Alowergrazingcoverwhencowsenterisalso

usefultore-establishagrazingwedgeaftermaking

silageorwhenallgrasscoversarethesameasa

resultofwintergrazing.Inthiscase,grazingata

coverof2200kgDM/hafortherstfewelds,then

increasingthislevelofcoveroverashortperiodto

2800kgDM/hatoregainthewedge,maybethe

bestoptiontore-establishasupplyofqualitygrazing.

Sheep on Grazing Land


4/195:4 Improvement through grassland management

Can sheep be useul to grazing managemento grass or the dairy herd?

Pros

Sheepwillgrazealloldgrass,sospring

grazingisofhigherquality

Theykeepontopofgrassgrowthoverwinter,

socowsarenotputtograzepasturesabove

therecommended2800kgDM/ha,asmost

UKgrasswillgrowtosomeextentallwinter

Extraincome.

Cons

Springcalvingsystemsrelyonover-wintered

grassandwintergrowthforgrazinginFebruary

andMarch.Sheepwilleatthatgrass

Sheepnottakenoffgrazinglandearlyenough

willdelayturnout

Grasstakendownclosetobareearthwilldelay

springregrowth

Oncesheepareremoved,allgrazingis

generallyatthesamelowlevel,resultingin

potentialofboomandbustofgrazingsupply.

Therewillbenothingtostartwith,thenonce

grassgrowsitsallreadytograzeatthesame

timeandsomecanpotentiallygobeyondthe

optimumof2800kgDM/habythetimecows

gettoit.Thissurplusmaybesilagedbutthat

canleavetoolittleforgrazingrequirements.

So what is the answer?

Grazingsheepinwinterisunlikelytobebenecial

foragrass-basedspring-calvingsystem,butitmay

haveadvantagesforotherproducers.

Sheepwillcleanpasturesnotgrazedhardenough

inautumn.Grasscarriedoverwinterwithdead

anddecayingmaterialinthebasewillreduce

grazingpotentialinthenewseason.

Whendeadandstemmaterialarelefttheywill

preventcowsgrazingdowntotheoptimumresidual

of1500kgDM/hainearlyspring.Iftheresidualislefttoohighinspringanddeadandstemmaterial

buildupinthesward,itwillreducequality,

palatabilityandgrowthpotential.

Grasswillgrowinlateautumnandwinter,aftercows

arehoused.Whenthereissignicantwintergrowth,

grazingmaybeatorbeyondthepreferredlevelof

2800kgDM/haatturnout,makingitdifculttoget

cowstograzedowntotheoptimumresidual.

Managing grazing sheep

Theproblemsofsheepgrazingtoomuchcoveroff,

delayingspringgrowthandleavingallgrazingat

thesamelowcovercanbeavoidedbyplanning

theirremoval.

Thisisbestmanagedbywalkinggrassfrequentlyand

notlettingthesheepgrazeallthegrassatonce.

Considergivinganareasuchas20%fortherstfew

weeksbeforemovingtothenext20%andsoon.

Takingthemoffgrassatdifferenttimeswillcreatea

minigrasswedge,withtheareagrazedbysheepin

Novemberreadyforcowsbeforethatgrazedby

sheepinJanuary.

Alternatives to sheep

Analternativeistograzeheifersorfaroffdrycowson

wintergrowngrassearlyintheyeartotaketheexcessoffandthencloseitupforanearlycutofsilage.

Theirmuckshouldnotreducesilagequalitywhen

stockarenotbeingfedabrousbuffer,keeping

mucklooseandeasilydispersedbysoilmicrobes

beforecutting.



Points to consider:

Getcowsoutearlierandinlater,donotuse

perceivedwetconditionstokeepthemin.Tracksandgatewaymanagementwillenablethis

Askwhetherthecentreoftheeldisdry

enough.Ifitis,butthegatewayislimiting

access,usemultipleentriesfromtracks

Ensureagrassresidualof1500kgDM/ha

Sheepmaybeanimportantgrassland

managementtool,allowingyouto

achievethecorrectcoversinspring

Globalwarmingmayleadtomoregrassgrowthinwinter.Thensheep

mayhelpmanagewintergrass.

Prepare or Turnout

Field covers at turnout

In the ideal situation all grazing felds would be

at dierent cover levels when you start grazing.

Whencowshavenishedgrazingoneeld,

ideallythenexttobegrazedwillhavejustreached

2800kgDM/ha,soitisreadyforgrazing.

Thisenablesaconstantsupplyofgrassavailable

atthecorrectstagenutritionallyforthecowandfor

maximumphysiologicaloutputforthegrasscrop.

ForexampleseeFig 5.1a(on pages 5-7)

Creatingthedifferentlevelsofcoverrequiredineach

eldformswhatisknownasagrasswedge.Aspring

grasswedgeisparticularlyimportantforspringblock

calvingherdsonalowconcentrateinputsystem.

To set up a grass wedge or spring:

Beginplanninginthepreviousautumn,while

cowsarestillgrazing

Shutupsomeeldsearlyintheautumntoallowgoodlevelsofcovertobecarriedover

tospring

Grazeothereldslaterintoautumn

Considertheslowbutcontinuinggrassgrowth

ratesoverwinter.

Fieldsshutuprstinautumnbecometherst

grazingeldsinspringandthelaterautumngrazed

eldsfallinbehind(see Figure 5.1a feld 1).

When there is no grass wedge

Ifallgrassislefttogrowto2800kgDM/habefore

turnout,therstfeweldswillbeatthecorrectcover.

Butbythetimecowsgettotheremainingeldstheywillhavegrownbeyondtheoptimumforgrazingwith

toomuchcover.

When grass growth is beyond the optimum or grazing:

Grasswillbereducinginquality

Cowswillndthisdifculttograzedownto

theoptimumresidualof1500kgDM/ha

Leavingalongresidualmeanssubsequent

regrowthwillbelowerinqualityandyield Itwillbedifculttogaincontrolandestablish

agrazingwedge.

When turnout may be delayed

Groundconditionsorthecowmanagementsystem

maypreventearlyspringgrazingandinsuch

conditionsalleldsshouldbegrazedrightdownin

autumn/winterwithdrycows,youngstockorsheep

toavoidcoversinexcessof2800kgDM/haatturnout.Thenatturnoutallgrazingeldsmaybeat

similarcovers,givingasimilarscenariotothatseen

aftersilaging.

This can be avoided by:

Onlyletgrassgrowto2200kgDM/haandthen

startinggrazing.Therstfeweldswillbebelowthe

optimumforgrazingbutasgrasscontinuesgrowing

onungrazedelds,coverswillgraduallyincrease

untilcowsaregrazingat2800kgDM/ha.Thiswillestablishawedgeforthesecondgrazinground.



Asageneralprinciple,introducegrazingslowlyso

therumenhasachancetoadapt.Startwith5kg

DMofgrazedgrassandtheremainderofintakefromthewinterdietandincreasegrazingintakes

overtimetoallowtherumenbugstoadapt.

Theadvantageofthisisthatiftheweatherchanges,

cowscangobackontowinterdietwithoutany

problem,havingtakenadvantageofthecheapest

forageandhavingstartedtosetupagrasswedge

forthecomingseason.

The frst essential or successat the start o the season isto achieve a good arm grasscover at turnout (Section 4).

Thisensuresthecowshaveaccesstosufcient

goodqualitygrazingfromtheoutset.

Ahead o turnout it is also important to: Decidewhicheldstograzerst(Section 4)

Ensurefences,gates,roadways,tracks,water

troughsandpipesareingoodcondition

Checkelectricfencingisworkingwell

Isthegatewaythelimitingfactor

usemultiple-entryslipgates.

Fields that are to be cut or silage cansaely be grazed until mid-April.

Case study

Grazing silage grounds early in the season

Forthelastnineyears,AndrewStevenshasbeen

grazinghissilageeldsearlyintheseasonbefore

shuttingthemupforsilage.

Andrewruns316autumncalversyielding7040

litresat4.19%fatand3.45%protein(totalsolids

of555kg),nearLechladeinGloucestershire,

withalargeemphasisongrazing.

Grazing silage felds allows:

Anearlyturnout

Grasstobesubstitutedforconcentrate

Reductioninfeedcostswithout

anymilkyieldloss

Savingsonwinterhousingcosts.

How does he do this?

Paddockstobegrazedearlyinspringareshut

upinOctoberwithareasonablecover.Andrew

reckonsheachievesthebestresultswhenhetakes

agoodamountofgrassoverwinter,asthengrass

canstarttogrowwellstraightawayaftergrazing.

Good grass cover over winter:

Stimulatesagoodrootstructure

Providesgrassforanearlyturnout

Allowsgrazedgrasstotakeonnutrientsandmoisturequicklyandeffectivelyaftergrazing.

Theaimistostartgrazingbyabout20February.

Andrewmayputon25kgofN/hainFebruary,if

hethinksitsnecessary.



Eachpaddockisonlygrazedonce,withcows

allocatedenougheachdaysotheygrazedown

toaresidualof1500kgDM/ha.

WithAndrewsset-up,thismeanseachpaddock

isdividedintothreebyastrandofelectric

fencingandcowsgetathirdforeachgrazing.

Thisalsoeliminatesanyregrazingofregrowth,

whichhasaseriousnegativeeffectonthe

regrowthandsubsequentyieldofsilage.

In2007,Andrewwasabletograze19haofhis

24haofsilageground.Thisareaisdictatedby

theweather.Heonlygrazeswhentheconditionsareideal,lookingattheforecast,walkingthe

eldsandplanninggrazing,asanydamagewill

increasethecostofeverytonneofdrymatter.

Whengrazingsilageground,the300cowsare

allocated0.8hato1.2haatatime,depending

ongrassavailability,toachieveagoodresidual

(cowsareabout500-550kgliveweight).

CowsaretakenoffsilagegroundsinthersthalfofMarchandthenprogressaroundthe

grazingarea.Oncecowscomeoffsilage

ground,itreceives125-140kgN/haand75kg

ofpotash/ha,ashisgroundispotashhungry.

Sheepwereonceusedinwinterbuthavenow

beenreplacedbycowsgrazingaslongas

possibleintheautumn,generallyintoDecember

andanearlystarttograzinginspring.

A typical analysis o silage rom groundgrazed until early March shows:

Dry matter 27%Crude protein 13.9%D-value 73ME 11.7MJ/kg pH 3.8NH3 4.5Sugars 1.3

Cowsarefed2/3maizesilage,1/3grasssilage

overwinteruntilturnoutwhengrazingreplaces

grasssilage.

Muck contamination o silage is not a problem when:

Inawellgrazedrotationalsystemthegrassisat

amaximumof2800-3000kgDM/haatentry

andgrazedto1500kgDM/ha,somuckmakes

contactwiththesoilandsoilmicrobesareable

todisperseit

Muckisreasonablyloosebecauseofthegrass

elementofthediet,whichaidsdispersal

Itisdispersedbyrooksseekingoutbugsand

anyundigestedmaizeinmuck.

Thephotographsbelowshowtheswardanditsbase,

demonstratingnoevidenceofmucktocontaminate

silage.Moreimportantly,thebaseisallfreshnew

growthgrowninspring,soitdoesnotcontainany

deadordyingleaforstemmaterialwhichwillreduce

silagequality.

Sward base (taken 3.5.07)

Oncesilagingstarts,cuttingheightisstandardand

notraisedbecauseoffearofmuckcontamination,

asthereisnomuck.



Thisgroundwascuton23Mayandpicked

upon24May.Andrewnormallyexpectsto

cutbetweenthe20and25Mayandwouldnormallyexpect27to28tonnes/hafreshweight.

Thegrassisalateperennialryegrassley.

Thephotobelowshowsstubblepost-silagingtaken

on25May2007,thedayaftergrasswaslifted.

Ascanbeseenfromthesephotographs,themowerwassetatanormalheightandthereislittleevidence

ofmuckfromthepreviousgrazing,despitean

extremelydryApril.Theverysmallamountofmuck

leftisnotenoughtocontaminatesilageandina

normalAprilwhenthereisraintherewouldbeno

muckleft.

Andrewshowsthatthispracticeispossibleand

successfulintermsofcowhealth,nutrition,grass

utilisation,performanceandmostimportantlyofall

businessefciencyusingresourcestothefull.

DairyCo research suggests that turningcows onto a new pasture in theaternoon could increase milk outputby over 32p/cow/day (Table 5.1).

Becausesugarsareattheirhighestlevelsingrass

andtheirbalancewithNisoptimalintheafternoon,

intakesinthersthourofgrazinghavebeenshowntoincreasebyover15%.

Thereislittleeffectonoverallforageintakebuta

switchtonewpastureintheafternoonhasthe

potentialtoraisedailymilkproductionbyover5%

asaresult.

Table 5.1: Timing o New Forage Allocation

Time oAllocation

Value o

Improvement*(p)

AM PM

Forageintake

rateinrsthour

(gDM/min)

46.6 54.4

Forageintake/

day(kg)17.8 18.0

Milkyield**(litres/day)

21.8 23.1 32.4

* Assumes milk is worth 24.9p/l **Measured over last our weekso a 10-week study

Source: DairyCo Report 96/R3/06: The efcient use o grazedherbage by dairy cows (updated with 2008 fgures).

Turnout Tips Cowsshouldhaveanedgetotheirappetite

Thisedgeofappetitemaybeachievedbycows

runningoutoffeeduptotwohoursbeforethe

morningmilking

Grazethecowsforalimitedperiodinitially

(egthreehours)thenincreasegradually

Agoodleafyswardwillencourageintake

Startgrazingclosetotheyardwhereverpossible.



Rotation length

Grazingshouldstartin the spring whentheeldcoverreaches2100-2400kgDM/ha(Section 4).

Inthemainseasongrazingshouldstartineach

eldwhenthetargetpre-grazingpointisreached

(Section 3).

Pre-graze Target:

Fieldcoveris2600-3000kgDM/ha

Ryegrasshasatleasttwoandahal, preerably three, leaves.

Cowsshouldberemovedfromaeldwhenthesward

reachesthetargetpost-grazingpoint(Section 3).

Post-graze Target:

Fieldcoveris1500kgDM/ha

Aswardheightof4-5cmwithonequarter to one third o the areacovered in clumps no higher than8-10cm.

Theaimingrazingeachareamustbetoprovidean

allocationofgrassthatallowsthecowstoachieve

maximumintakewithoutgoingbeyondthepost-graze

targetandreducingsubsequentswardproductivity.

Throughouttheseasonitisimportanttoensurethere

isenoughswardinfrontofthecowsbutnotsomuch

thatitiswastedthroughreducedqualityorutilisation.

Thersteldisre-grazedoncetheotheravailableeldshavebeengrazedthetrickbeingtoensure

thatitreachesthepre-grazetargetatexactlythistime.

The key to ensuring this is to adjustthe length o the rotation betweengrazings to accommodate changingsward growth rates.

Using Field Cover Estimates

Individualeldcovermeasurementsmadewitha

risingplatemeter(Section 3)provideagoodwayofestimatinggrazingrotationlengths(Example 5.1).

Measurementsshouldbemadeforalleldsinthe

rotation,weeklyintheseason,tocaterforchanging

swardgrowthrates.



Example 5.1: Calculating RotationLength with Field Cover

FieldName orNumberand Area*

EstimatedFieldCover

SwardGrowth

Rate **(kgDM/ha)

Days toReachTargetCover

***(2800kgDM/ha)

A B(2800 -A) B

Mid-June

14.1ha 1700 90 12.2

22.8ha 1900 90 10.0

Average 11.1

MidJuly

14.1ha 1700 50 22.0

22.8ha 1900 50 18.0

Average 20.0

* Calculations should be carried out or all felds availableor grazing

** Sward growth rates should be obtained rom individual armsward growth curves (Worksheet 2) or typical fgures (Section 4;Figure 4.2).

*** Target feld cover or the start o grazing should be 2800kgDM/ha.

Thelengthofgrazingrotationcanbeexible

dependinguponthecircumstances.Rotational

grazingallowscontrolovertheareaallocated

forgrazingeachdayandthisabilitytoallocategrazingisanimportantpartofintensive

grazingmanagement.

The key eects rotation length has are:

Controllingtheareaandamountofgrazingthat

cowsareallocatedand,therefore,theirintakeofgrass

Controllingthetimeperiodbetweensuccessive

grazings,sograsshasenoughtimetoregrow

andallowallocationofgrassattheoptimum

growthstagetomaximiseitsfeedqualityand

quantity.(Holmesetal2003).

TheseareillustratedinTable1,Factsheet15.

Reducing the area grazed each day increases rotationlength and has three main eects:

Grassofferedandeateneachdayisreduced,

atleastintheshort-term,whichcanbeuseful

whenthereisagrassshortage

Paddockshavealongerregrowthperiod.This

canbeusefulwhengrowthrateisslow

Grazingintensityisincreased,solessavailable

grassiswasted.Thiscanbeinuencedby

supplementaryfeed.

Thegrazingofferedeachdayshouldbebasedon

theanimalfeedintakeneededandpre-grazingcover.

Therefore,rotationlengthisabalanceofshort-and

medium-termfeedmanagementdecisions.This

explainswhymanyfarmsuserotationsof20to30

daysinspringandnearer100daysinwinter.

(Holmesetal2003).

Worksheet 6 provides a pro ormaor estimating rotation lengths romfeld covers.



Allocating Swards

Sincerotationlengthsmayneedtochangequitemarkedlyovertheseasonthechangesshouldbe

madegraduallyonanalmostcontinuousbasisto

caterforchangingswardgrowthratesidentied

throughregularmonitoring.

Havingdeterminedthebestrotationlength,sward

allocationscanbemadeonthebasisofcownumbers

andintakes(Example 5.2).

Example 5.2: Sward Allocation

Demand: 150cowsproducing25litres/dayfromspring/earlysummergrazingrequire150x18kg

DM/day(Section 4; Table 4.5 & Example 4.6)=2700kgDM/day.

Supply:Eachhectareoffers2800kgDMattheoutsetandisgrazeddownto1500kgDMproviding

1300kgDMpergrazing.

Area:Thearearequiredtomeetthedailydemandis27001300=2.1ha.Witharotationlengthof

24daysthetotalarearequiredis2.1x24=50.4ha.

Astherateofswardgrowthslowsdowninthesummer

months,pastureswillrequirelongertore-growtothe

target2800kgDM/hapre-grazeeldcover.

Toaccommodatethis,therotationlengthwillneed

tobeextendedbybringingmoreeldsintothe

grazingcycle.

Alternatively,ashortfallinavailablecoverwillarise

andsupplementationmaybenecessary(Section 6).



Shortalls and surpluses

Grazing shortalls invariably costmoney in lower perormance and/or increased supplementary eeding.

Grazing surpluses also cost money,

primarily in wasting high quality grass.

Monitoringeldcoverovertheseasonallowslikely

imbalancesingrazingsupplyanddemandtobe

cateredforaheadoftime.

AveragefarmcoversfallingfromtheendofApriland

duringtheperiodMayearlySeptembergenerally

indicateashortfallislikely.

Ontheotherhand,increasingaveragefarmcovers

generallyindicateasurplus,particularlyiftheyare

greaterthan2800kgDM/ha.

Assessing Field CoverAvailability (Feed wedge)

Regularplottingoftheindividualcoversofallelds

intherotationonagraphenablespotentialsurplusesorshortfallsinforagesupplyinthenearfutureto

beidentiedbytheshapeofthecurveproduced.

Agraduallyincreasingstraightlineindicatesgood

coveravailabilityintheshort-term(Figure 5.1a).

Arelativelyatorconvex-shapedcurvewith

generallyhighvaluessuggestsashort-term

surplus(Figure 5.1b).

Aushapedorconcavecurvewithanumberof

relativelowvaluesindicatesaloomingshortfall

(Figure 5.1c).

Assessing Pasture Balances

Calculatingpasturegrowth:demandbalances

(Section 4)isanotherusefulwayofidentifyingpotentialgrazingsurplusesorshortfalls

duringtheseason(Example 5.3).

Example 5.3: Pasture Growth:Demand

Balances (Section 4: Example 4.6)

Demand: 150cowsproducing25litres/dayfromspring/earlysummergrazingrequire:

150x18kgDM/day=2700kgDM/day.

Growth: 30haofpastureproducing80kgDM/ha/dayis30x80=2400kgDM/day.

A shortall o pasture is likely to occur here asgrowth is not meeting demand. Action is needed igrowth appears to be continuing at this level.

Growth:30haofpastureproducing120kgDM/ha/dayis30x120=3600kgDM/day.

Pasture growth is well in excess o demand here anda surplus o grazing is looming. Action is needed igrowth appears to be continuing at this level.



Figure 5.1: Field Cover AvailabilityChart (Feed wedge)

(a) Ideal Situation

3500

3000

2500

2000

1500

1000

500

0

kg/DM/ha

Field number

1 2 3 4 5 6 7 8 9 10 11 12 TargetAverage

FarmCover

AverageFarmCover

(b) Surplus Looming

3500

3000

2500

2000

1500

1000

500

0

kg/DM/ha

Field number

1 2 3 4 5 6 7 8 9 10 11 12 AverageFarmCover

TargetAverage

FarmCover

(c) Shortall Looming

3500

3000

2500

2000

1500

1000

500

0

kg/DM/ha

Field number

1 2 3 4 5 6 7 8 9 10 11 12 AverageFarmCover

TargetAverage

FarmCover

Worksheet 7 provides a proorma or plotting feld coveravailability charts (Feed wedge).

Addressing Sward Surpluses

Grazingeldcoversinexcessof3000kgDM/haresultinlowerpastureproductivityandquality

(Section 3).

Grazing covers greater than 3000kgDM/ha may reduce milk production.

Whenswardslooklikebeingor,arealreadyin

surplusthereareanumberofactionsthatcanbetakentoredressthesituation.

Short-term Actions Closesomeeldsandcutthemforsilage

Thisisagrasslandmanagementstrategyandas

suchtakingasmallamountofsilagemaycost

morethanthemainsilageoperationpertonne

ofsilagemade,butitwillpayintermsoffuture

grazingquality.Itmaybeeasiertobaleand

wrapasmallarea,ratherthanopenaclamp.Resultingbalescaneasilybefedbackinatime

ofdecit.Ifasurplusoccursintherunuptothe

mainsilagetimeitcanbetakenwiththemaincut

Topping,usingamowerearlyintheseason,

mayreducere-growthinthefollowing

rotationbutwillhelptomaintainquality.



Longer-term Actions Increasethestockingdensityearlierin

theseason

Increasethetotalnumberofstockcarried

Reducetheareainthegrazingrotation

Reducefertiliser/slurry/manureuse

Turnoutearlier/stayoutlater

Carrylesspastureoverwinter,ifatall.Forawet

farm,itmaybeworthwhiletakingcoverright

downintheautumnwithstock,usinglow-yielding

cows,drycows,heifersorsheep,sothatgrassdoesnotgobeyondagoodentrycoverof

2800kgDM/haatturnout.Butthismayleaveall

grazinglandatthesamelevelofcoverwhichwill

requirecarefulmanagement(see page 5-3)

Feedlesssupplementsatgrass

Considerchangingthecalvingpatterninsome

oralloftheherdtobettermatchswardpotential.

Factsheet 13 sets out a simple systemor planning supplementary eedingat grass.

Addressing Sward Shortalls

Grazingswardstolessthan1500kgDM/haor

below4-5cminheightcompromisespasture

productivityandquality(Section 3).

Grazing shortages seriously limit the

ability to produce milk rom grass,increasing production costs markedly.

Whengrazingisinshortsupply,orlookslikeitcould

besoon,thereareanumberofactionsthatcanbe

takentoredressthesituation.

Short-term Actions Increasetheareainthegrazingrotation,

ifpossible

Introduceaforagebufferfeed(Section 6)

Avoidcontinuingtoruncoverdown,

compromisingre-growthsaswellascowfeeding

Considerdrying-offthelowestyieldingcows.

Longer-term Actions Grazesilagegroundbeforeclosing

Builduphighercoversgoingintowinter

Increaseearlyfertiliserapplications

Growlucerne,stubbleturnipsorforagepeas

foradditionalsummerfeeding

Growforagerape,kaleorfodderbeetfor

autumnandearlywinterfeeding

Includewholecropcerealsintherotationfor

useasabufferfeed

Plantobuysupplementslikebrewersgrainsorpressedpulpwhentheyarefavourablypriced

Considerchangingthecalvingpatterninsome

oralloftheherdtobettermatchswardpotential

Considerrenewingolderpastureswithhigher

outputryegrass/clovermixtures(Section 12).



Feeds per feld

Havingestablishedthegrazingrotationanddaily

swardallocationrequired,thenalcalculation

thatneedstobemadeingrazingmanagementis

thenumberoffeedseacheldorgrazingarea

willprovide.

The primary aim should be to provideaccess to new grazing each eed, withcows spending a maximum o oneday on the same pasture (Section 4).

Calculating Feeds per Field

Eacheldinthegrazingrotationshouldbeassessed

forthenumberoffeedsitwillprovide(Example 5.5).

Thefeedsprovidedwillnotalwaysbeawhole

number.Sofractionsofafeedneedtobeadjusted

upwardsordownwards.

Thisshouldgenerallybedonetothenearesthalf-feed

ontheassumptionthatcowsshouldbemovedafter

eachtwice-dailymilking.

Three-times-a-daymilking,ofcourse,allowsfeed

numberstoberoundedtothenearestthird.

The decision to round up or down should depend on:

Field cover highcoverround-upnumberoffeeds;lesscover

rounddown

Sward quality highqualityround-upnumberoffeeds;poorer

qualityrounddown

Thenumberofupwardanddownwardadjustmentsneedstobethesameiftherotationlengthisto

bemaintained.

Moving cows to new pasture atereach milking is a good way omaximising orage intake, particularlyas the season progresses.



Pasture utilisation

Assessingtheactualforagesuppliedbygrazingat

intervalsduringthegrazingseasonprovidesa

valuablecross-checkonlevelsofmilkproduction

actuallybeingachievedfromgrassaswellasactual

pastureofferings.

Italsoallowstheefciencyofswardutilisationto

becalculated(Section 2).

Sward Utilisation Target: 70-80%.

Wheregoodqualityswardsaregrazedclose

totheidealpost-grazingpointutilisation

valuesmaybehigherthan80%.

Swardutilisationtargetsofcloserto100%are

notadvisableasanimalintakesarelikelytobe

compromisedatthisefciencyofpastureuse.

Swardutilisationsgreaterthan100%

indicateswardsarebeingovergrazedand

subsequentre-growthwillbecompromised.

For most purposes a simple DMcalculation will be quite sufcient toassess and monitor utilisation efciency.

Similarcalculationscanbecarriedoutto

establishtheefciencyofMEutilisation.

Theresultismoreaccurateasittakesaccountof

thestageoflactationofthecowbutitisoverly

complicatedforpracticalday-to-dayuse.

Example 5.4: Calculating Field Feed Numbers

Total GrazingArea (ha)

AverageRotation

Length (days)

Average DailyAllocation (ha)

Size o EachField (ha)

Numbero Feeds inEach Field

(Calculated)

Number oFeeds in Each

Field (Adjusted)

A B C(AB) D (DC)

56 20 2.8 5 1.8 2

6 2.1 27 2.5 2.5

8 2.9 3

Etc.......

Worksheet 8 provides a pro ormaor calculating eeds per feld.



Calculating Sward Intake

Swardintakeiseasytocalculatefromtheinformationalreadyrecorded(Example 5.5).

Example 5.5: Sward Intake

Total

Grazing

Area(ha)

Rotation

Length

(days)

Daily

Allocation

(ha)

Pre-graze

Field

Cover(kg

DM/ha)

Post-graze

Field

Cover(kg

DM/ha)

Field Cover

Allocated

(kg DM/ha)

Total

Pasture

Oered (kg

DM/day)

Milking

Cow

Numbers*

Individual

Pasture

Oered

(kg DM/

cow/day)

A B C =(A B)

D E F =(D E)

G =(C x F)

H (G H)

45 19 2.4 2800 1500 1300 3120 180 17.3

* High-yielding cows (over 15 litres/day) only. I necessary do a separate calculation or the lower yielding group.

Worksheet 9 provides a pro orma orcalculating sward intake.

Measuring Sward Utilisation

Swardutilisationcanbestbemeasuredbyassessing

theactualintakeofswardDMcomparedtothecover

allocated(Example 5.6).

Swardintakeisestimatedeitherbycalculation

(Example 5.5)orbydifferencefromtheintakeofallotherfeedsandthepredictedDMintakeofthecow.

Example 5.6: Estimating Sward Utilisation Efciency

Cover Allocation: 1500kgDM/dayisprovidedtoaherdof

100cows,givinganindividualallocation

of1500100=15kgDM/head/day.

Sward Intake: Cowsweighing600kghaveaDMintake

of18kgandareconsuming6kgDMas

cakeintheparlour,givinganintakefrom

grazingof18-6=12kg/head/day.

Sward Utilisation: Theefciencyofutilisationistheactualintakedivided

bytheallocation:1215kg=0.8(or80%).

Factsheet 14 provides advice onrearing heiers at grass.



ThepredictedDMintakeofthecowisapproximately

equivalentto3%ofbodyweightforcows

weighing550,600or700kgthismeans16.5kg,18kgand21kgrespectively(swardDMintake

beyond18-19kgDMisnotgenerallypossible).

Getting Grazing Back Under Control

Thisgenerallyreferstonotachievingthecorrect

residualcoverof1500kgDM/ha.Mistakeswill

happenanditisnotalwayspossibletograzeto

1500kgDM/ha.Forexample,cowsarelesslikelyto

achievetheresidualonareallywetday,butitisimportanttocorrectthepoorresidualleftbycowsso

futurequalityisnotlost.Onewaytomonitorresiduals

istoscoreeacheldwhencowscomeout.For

exampleonascaleof1-5,with1beinggoodand5

poor,makeanoteofthisinadiary,allowingactionto

betakenoneldswithascoreof1,2andpossibly3.

There are a number o ways to correct a poor residual:

Considerwhethertoomuchwasallocated.Ifthis

isso,thentryreducingtheallocationandseewhethercowsgrazeharder(sometrough-fed

cowsdoneedabitoftraining)

Ifthereisnottoomuchleft,goinimmediately

behindthecowsandtopthearea.Amoweris

best,asitmakesacleanercutanddoesnot

tendtopushgrassdownlikeatopper.The

mowerwillcuttoabout1500kgDM/ha,

restoringagoodresidual.Donotdothisif

thereisamassofgrassasmowedmaterial

willshadeoutnewgrowth Mowgrass12to24hoursbeforegrazing.

Thisisparticularlyusefullaterintheseason

whenseedheadsareappearing,butitdoes

requiredryweather.Useamowerandwilt

grassforupto24hours.Experiencefrom

aroundthecountryshowsthisworkswell

(however,ithasbeensuggesteditdoesnot

workwellwithJerseys)

Photo 13 below shows a feld ready or cows tograze ater mowing and wilting. Photo 14 shows

another feld which has been mowed, wilted andgrazed. This photo was taken a ew days atergrazing and good regrowth has been achieved.

Photo 13 Grass mowed and wilted pre-grazing.Courtesy o Will Edwards

Photo 14 Regrowth ater mowing, wilting and grazing.

Courtesy o Will Edwards Regrowtheareawithapoorresidualfora

weekorsountilthereisafreshswardandthen

grazewithotherstock,suchasheifersandmake

themgrazeithardtoachievea1500kgDM/

haresidualthenallowtoregrowto2800kg

DM/haandre-enterthegrazingrotation

Designatetheareatobesilagedinthenextround.

Themowerwillthenreinstateagoodresidual.

Thesestrategiesarenotanexcuseforpoorgrazingmanagement,asthecheapestwaytogetthe

optimumswardregrowthisforcowstograzedown

to1500kgDM/ha.However,mosteldsmayneed

oneoftheabovetechniquesinthegrazingseason.

Ifacertaineldorpartthereofconsistentlyhasa

poorresidual,itmaybeapalatabilityissueanditis

worthconsideringgrasstypes,soilpH,soilindices,

(P,Kandotherelements)previouseldhistory(such

asexcessivedirtywaterand/orslurryapplications).

Grassvarietiesalsohavedifferingpalatability.


19/19

Summary TheidealPre-grazePointiswhenryegrass

reacheseldcoverof2800-3000kgDM/ha

Grazingshouldcontinueuntiltheswardis

4-5cmhigh(withonequartertoonethird

oftheareacoveredinclumpsnohigher

than8-10cm)oreldcoverreaches

1500kgDM/ha

Grazingrotationlengthcanbestbe

monitoredandadjustedthroughouttheseasonusingeldcovermeasurements

Monitoringeldcoverandaveragefarm

coveronaregularbasisallowspotential

grazingsurplusesorshortfallstobeidentied

andaddressedbeforetheycreateproblems

Carefulallocationoffeedspereldonthe

basisofareaandrotationlengthwillensure

themostefcientutilisationofpasture

Targetswardutilisationefciencyshould

be70-80%.

Section 2: CalculatingtheCostofYourFeeds

Section 3: AssessingYourPasture

Section 4: PlanningYourGrazing

Section 6: SupplementingGrazing

Section 12: RenewingSwardsSection 14: GrazingHigh-yieldingCows

Section 15: Factsheet13:TheCrichtonSTARSystemFactsheet14:RearingHeifersatGrass

Section 16: Worksheet5:RotationLength (Three-leafAssessment)

Worksheet6:RotationLength

(FieldCoverAssessment)

Worksheet7:FieldCoverAvailability

Worksheet8:FeedsperField

Worksheet9:SwardIntake

Seealso...

Documents

Grass Programme Sec 5