Recent developments in the handling and weighing of farm animals

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ilBCEN’T DEVELWMWTS IN THE HANDLING AND WEIGHING OF FARM AIUIMW

ABSTRACT Turner, Md.B. snd Smith. EA., 1976. Recent developnlentr in the handling and weighing of farm PninuL. Liue#t. Rod. Sci.. 2: 280-296. A mti-autormtk unit for had&g piga Uwoqgh I weigher ia described. ‘Ike crates are wed in aertm, the first bei- a bmdlig crate where identikation in done before the pigs srel~oneacsLbasLnLo~w~aaLs.ThcLt~haspnwnet~yoperaterlgs~ and a fkw whkb eeuacnthe pwence of a pQ. U&U, ektronk weight averagkg. the unit enableaone man to ww about 1011pi@b wilboM mktance. With a second man. throughputa of about 200 pip/h are pouible Simiku pincipler are applied to sheep end cattIe weighlug. Poaible futlvs developments are diruued.

i?JTRODLXTlON

In fat&o& production In G.B. one of the major operations,involvingthe we of two or three men, fs that of weighingthe animale.Due to this high

labour requirement,weighingtendsto be done only when the animalsare Botr, accuracyof weighingand thought to be nedy ready for rnwa. high throughput of animalsare immt, but with the majority of weighers now availablethesetwo requireme& are opposing.In generala man has to estimatethe readingof a flickering pointer on a dia! - the quicker he does this, the lessaccure&e the readt but the bigher the throughput. On experimental farms the needia p&&ly evenIpeatcf for accurateweming and high throughput, althoughhandllngia somewhateasierdue to the animalsbecoming accustomedto the we&h& procedure.Our studiesat the National Institute of Agricultural Engineering,SiIsoe,G.B. were divided into two basicareasthe actual weighingprocea and the handIingof the &male. WEWHINCI

It wasdecidedat the outset that electronic weigM registrationand recording were likely to be most useful for removingthe subjectivejudgementof the

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man watchinga flickering pointer. After examiningchart recordirqpof thi* electrical signals coming frum a transducerfitted to a conventronalweigher. two electronic circuits were investigated(Smith and Turner, 1974). The first looked for steadyperiods(i.e., no fluctuations in the electrical signal)lasting longerthan 120 msec and recordedthe weight readingat those times. The secondcirc:lit averaged(or integrated)the electrical signalcorresponding to the weight fx 3 sec. In both c&es the final readingwas held steadyon a digital pane’meter. Both circuits gavean accuracyof about + 1%of the correct weight I? 99.8%confidencelevel. l-fowever,in trials with pigs, on 20-33 occasionbout of every 100 t,hesteady period detector failed to producean answerwithin the desiredtime of 10 set and this approachwasabandonedin favJur of the weight averagingmethod. It is important in the latter method that the crate be dampedonly lightly and equally for both upward and downwardrnotiorr otherwisebiasedresultswill be obtained in casesof severe vibration. The electronicweight-averaging unit as finally developedis shown in Fig. 1 togetherwith the electrical transducerfitted to the back of the dial of a conventionalweigher.In applicationswherea record of both identity and weight is required,such as on experimentalfarms or institutes, a complete datarecordingsystemcan be addedto the basicelectronic unit. Fig. 2 showsthe equipmentinstalled at the Hill Farming ResearchOrganization,G.B., for recordingon punchedtape and printed sheetthe identities and weights of sheep.The identity is manually insertedon the keyboardwhereuponthe weight is automatically recorded.

FL. 1. A Unaar tranuducer mounted on the back of the dW of a cqnventional spr@weigher and Wet)

the

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eiectronic weight-averagingunit and transducer. (This is anN.I.A.E.

HANDLING

Bearingin mind the problemsoccurring in conventionalweighingsystems it was thought that, for pigs, two crates in seriesat the end of a broadly taperedinlet race would provide a mlution, in that pigs in the inlet race would be leasreluctant to move forward if they could sensethe presenceof another pig in either of the two crates.The first crate was simply a short parallel-sided race about 2 m long and 46 cm wide separatedfrom the taperedinlet race by a folding gate(Fig. 3). Tne secondcrate, where weighingwasto be performed, wasa conventionalweighcrate of the simple duaLspringsuspensiontype modified in the following manner.A vertical gate was fitted to its entrance MI that as the gateopenedit would not be impededby an animal, neither would the animal be forced backwardsor forwards by the gate.This gate was not aIlowed to descendto ground level but wasstopped 20 cm abovethe floor level of the weighcrate. This encouragedthe next pig to root under the gate and thus speededthe subsequententry of this pig. Both this gateand the conventionally swingingexit gate were poweredby pneumaticrams,Sheetmetal width restrictour were fitted either side of the inlet half of the crate to prevent pigs t.u.rningaround and alsOto biank ofi the sides.This encouragedthe pigs to rush to the exit end of the crate and attempt tc escapefrom there rather than pausinghalf-way along to look out sideways.The floor of the crate was pivoted at the inlet end and supportedby a stirrup at the exit end. The t?p of tide:stirrup restedon a pneumaticvalvethus acting as a pig-sensingdevice. Fig. 4 showsthe cornpI& weighingand handlingunit in useon a local farm. The pneumaticcircuit is shown in Fig. 6. The operatingsequenceat the weigheris as follows: (i) open the folding gate and allow one pig into the first crate;

Fig. 3. The first cruts of the pig weighing unit showing the queuing action it produces. (‘MS Is ma W.I.A.E photograph.)

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circuit IQ. 5. Thepneumatic

for the pig weigher.

(ii) shut the folding gate and identify the pig; (iii) open the inlet gate to the weigher; (iv) urge the pig through into the weigher,shut the inlet gate and start the weight averagingpracei38. (v) get the next pig into the first crate, identify it; (vi) record the weight of the first pig and pull the releaserope - the inlet gate automatically reapens when the pig leavesthe weigh crate. OPERATIONAL EXPERIENCE SeveralUlousandweighingshave beenperformed with this unit without injury to any animal and ite performancehas beenvery satisfactory.The cycle time for the unit is about 7 aecwith an additional 3 set being required for weight averaging,giving a maximum potential throughput of 360 pigs/h. In practice, overall rates (pen-to-pen)of about 100 pigs/hour can be achievedby one man without assistance.With another man servicingthe weighingareawith pigsand taking the weighedanimalsback, a throughput of about 200 pigs/hour can be achieved. An additional feature of the pneumatic circuit is that by holding down the rope operating the releasevalve, the operator can passpigs biraight through the weigher if their weight is not required. To achieveoptimum performanceattention must be paid to the designof inlet races,hoMing pens and the meansof getting the pigs out of and back into their pens. FUTUREDEVEXBPMENTB With the advent of automatic identification devicesfor ar&naIs(Bridle,

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1974) there are no tectnical reasonB why aut.omf&cV&o&d not beincludedLtaw~~?Pystemand~usrel~tbe~9jan~ duties. i’sr experimentalstationsit should be mbie to dsrbo 811~B+I weighingsystemin which anhnalecould be madeto ~dk WIcmdiy ovw II ungatedweighplatform a9part of thetr daily routbW. The useof compressed air to power weighcratesMd other &WIdl@ devlca htlsgreatpotential for sheepand cattle as well BBpi@ At S&mesn erpafme~ti cattle crate poweredby compressed air ( F’ilby and Turner, 3978) has beeain serviceon a 1000 head beefunit for over a year and the eggeof opsa%rl and increasedsafety of the operatorappearsto be of great ben&t. &HI.W10 Ooo weighingsof steersbetween100 and 400 kg havebeenperfczmedin the crate without injury to animalsor man. Electronic weight regi&a&n her bee!n usedand throughputaof about 80 steers/h(pen-to-pen)are ty@cal for a two man team. ACKNOWLEDOEAdENTS

The authorswish to acknowledgethe help and encouragement givento -hem this work by their colleaguesat N.I.A.E. md meral membersof tie farmingcommunity, in particularMesrusA.R. Hall, A. Chandler,G.A. Wright, N. Finch, I). and E. Masters,and K. Thornton. Thanksare also due to the Meatand LivestockCommission,St&fold; DowntngBras., Woe; the National AgriculturalCentre,Stoneleigh;and ManderCollegeFarm for allowing us to usetheir facilities in the development. stagesof this work. during

REFEREKCF,c Bridle, J.E., 1974. Automatic Dairy Cow Mentif~cation Leading to Milk YMd Recording meI Feed Contd. Rot. I.F.A.C. Sqmp. Autom. Control Agric., Saskatoon. S-k., June 1974. Secl.ES,pp. l-10. FHby.D.8. and ‘hmer, M.&B., 1973. L&stock Weighing. Rot. Subj.Day L&eat. Feed.

Wdghtrig.N.I.A.B, Sllmx. October18th, 1973. Rnlth. R.A. amdTurner.M.J.B.,1974. Electroniceidsfor um in faktock weighin&J. A@. Ba#. Ran., 19: 899-311.

ZUSAMMENF ASSUNG