动物采精方法.docx

动物采精方法.docx

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动物采精方法

SemenCollection

Therearethreecommonly-usedtechniquesforcollectingsemen:

useofanartificialvagina,digitalmanipulation,andelectroejaculation.Thetechniqueuseddependsonthespeciesbeingcollectedandthedispositionoftheindividualmale.

TheArtificialVagina

Artificialvaginas（AV'stotheinitiated）areusedtocollectsemenfrommanyspecies,mostprominentlycattleandhorses,butalsosheep,goats,rabbitsandevencats.

PrerequisitestouseofanAVarethatthemalebeconscious,notsignificantlyfrightenedofpeople,andmoreinterestedinejaculatingthaninkillinghumans.

AnAVusesthermalandmechanicalstimulationtostimulateejaculation.Asshownintheimagetotheright,anAViscomposedofatubewithanouterrubberliningthatwillholdwater,intowhichisplacedaninnerlinerthatislubricatedjustpriortouse.Theouterlinerisfilledandpressurizedsomewhatwithwaterat42-48degreesCelsius.ShownbelowareAVsdesignedforusewithbulls（bottom）andrabbits（top）.TheapparatusinthemiddleisatypeofAV,usuallycalledadirectorcone,whichisusedtocollectsemenfromdogs.

Tocollectsemen,themaleisallowedtomountandthepenisisdivertedintotheAVwhereheejaculates.ItisbesttoallowthemaletothrustintotheAVratherthantryingtoslidetheAVontothemale'spenis.Whatthemalemountsdependsonhisspeciesandtemperment.

Femalescanbeused,butunlesstheyareinestrus,theyrarelyenjoyparticipatingintheprocess,whichcaneasilyleadtoinjuryofanyandallofthoseinvolved.AnotherproblemwithusingafemaleasateaseristhatifyoumisswiththeAV,thefemalecouldbebredorpossiblytransmitvenerealdiseasetothemale.Forcollectingsemenfrombulls,atrainedsteerisusuallyused.Inthecaseofstallions,aphantom（"dummy"）isapopularchoiceforamount.

DigitalManipulation

Manymalescanbeinducedtoejaculatebyapplyingpressureandmassagetothepenis.Afterthemalebecomesaroused,adirectorconeofsometype,attachedtoacollectiontube,isslippedoverthepenistofacilitateharvestingthesemen.

Thistechniqueiscommonlyusedforcollectingsemenfrompigsanddogs.Aninitialtrainingperiodcanbehelpful,andhavingafemaleinestrustoarousethemaleoftenisuseful,particularlywhenthemaleisshy.

Anothertypeofmessageusedoccasionallywithbullsistostroketheampullae（terminalvasdeferens）,seminalvesiclesandprostateglandthroughthewalloftherectum;inalmostallcases,thebullmustberestrainedstandinginachuteandsedatedtoallowrelaxationandextrusionofthepenis.Inconjunctionwithaurethralcatether,onecanobtainasterileejaculateusingthistechnique.

Semeniscollectedroutinelyfromchickensandturkeysusingaformofdigitalmanipulation.

Electroejaculation

Electroejaculationinvolvesapplyingaseriesofshort,low-voltagepulsesofcurrenttothepelvicnerveswhichareinvolvedintheejaculatoryresponse.Itsoundslikeanextremelyunpleasantexperience,butdoesn'tseemtocausemuchdistressinbulls（althoughtheydoneedtobesecurelyrestrained）,andisconductedunderanesthesiainmanyspecies.

Electroejaculationcanbeusedwithalmostanymammal.Withfewexceptions,electroejaculationistheonlytechniqueusefulforcollectingsemenfromwildanimals,inwhichcasethemaleisanesthetizedpriortotheprocedure.

Anotheradvantageofelectroejaculationisthatitdoesnotrequireamountanimal,andcanbeappliedinthefieldusingabattery-poweredunit.Finally,electroejaculationcanbeusedtoobtainsemenfromanimalsthatarephysicallyincabableofmountingduetomusculoskeletaldiseaseorinjury.Itisusedforcollectingsemenfromquadrapelegicorparapelegicmenwhodesireachildbutcannotejaculateduetospinalcordinjury.

Withbulls,wherethereisabundantexperiencecollectingsemenbybothartificialvaginaandelectroejaculation,thesamplescollectedusinganelectroejaculatorusuallyhavealargervolume（duetoexcessiveaccessoryglandsecretion）andalowernumberofsperm.

Threepiecesofequipmentarerequiredforelectroejaculation.Theelectroejaculatoritselfisapowersupplywithrheostatstocontroltheamplitudeofthedeliveredcurrentandlotsofcircuitrytopreventaccidentalelectrocution.Second,oneneedsacollectiontube,usuallyattachedtoalatexrubbercone（"lovingcup"）inwhichtocollectthesemen.Finally,thepulsesofcurrentareappliedthroughanelectroejaculatorprobe.Theprobeisinsertedintotherectumsuchthattheelectrodesliewithinthepelviccavity.

Olderprobeshadcircularelectrodes,whichoftencausedundesirablemusclecontractions;probeswithparallelelectrodesononesideminimizethisproblem.Threeprobesareshownbelow-theupperoneisacommercialproductforbullsandthelowerprobeswerehand-madeforusewithsmallleopards（middle）andferrets（bottom）.

Successfulelectroejaculationofananimaldemandsskill.Itisnotsimplyamatterofpunchingbuttonsandturningknobs,butrequiresfinesseindeterminingthepropertimingandamplitudeofpulsestoapplytoagivenmale.

SemenCollectionfromBulls

AlargemajorityofdairycowsintheUS,CanadaandEuropeancountriesareartificiallyinseminated.Artificialinseminationofbeefcowsisalsopopular,particularlyinpurebredherds.TheadvantageofAIovernaturalserviceisthatitfacilitatesrapidgeneticimprovementbyallowinguseofonlythetopbulls.Somebullshavesiredmorethan100,000offspringviaAI.

Semenismostcommonlycollectedfrombullsinbullstudsusinganartificialvagina,asdescribedbelow.Electroejaculationisanalternativemethodusedwithbullsthatcannotmountoraretoofractiousforeasyhandling（e.g.rangebulls）.Finally,semencanbecollectedbymessageoftheseminalvesiclesandampullaeperrectum.

SemenCollectionviaArtificialVagina

SemencollectionfrombullsusinganAVrequiresthreepeople:

onetohandletheteaseranimal,onetocontrolthebullandonetocollectthesemen.Itisimportantthatthecollectionareahavenon-slipflooringtoavoidinjuriesandbecauseejaculationmaybeinhibitedifthebullisnervousabouthisfooting.Bullsareheavyandshouldhaveregularhoofcare.Poorhoofconditioncaninhibitthebullfrommountingorcausepainwhendismounting.

Asteerismostcommonlyusedasateaserandmountanimal.Femaleteasersarenotrecommendedbecauseofthepotentialriskofintromissionandspreadingofvenerealdisease.Theteasershouldbeacalmanimaloftheappropriatesizeforthebullbeingcollected.

Thebackandrearquartersoftheteaserarewashedwithadisinfectanteverycollectionday.Itisalsocommonfortherearquarterstobeclippedroutinely.Thebull'spreputialhairshouldbeclippedinpreparationforusingtheAV.Thesesanitaryprecautionsareintendedtominimizemicrobialcontaminationofthesemenbeingcollected.

Forcollection,theteaserispositionedstraightinfrontofthebullformounting.Oftentimes,ithelpstoarousethebullifthesteerisledaroundthecollectionarenawiththebullbehind,thenstoppedabruptly,similartothebehaviorofacowinestrus.

Theartificialvaginal（picturedatright）usesthermalandmechanicalstimulationtostimulateejaculation.ThelineroftheAVisfilledwithwaterat42-48degreesCelsius,andtheinnersurfaceislubricatedwithsomethinglikeK-Yjelly.Aninsulatingconeisplacedovertheendfromwhichthecollectiontubeprotrudestoavoidsubjectingthesementotemperatureshock.

Falsemountingisaneffectivewaytosexuallystimulatethebull.Providingtwofalsemountswithtwominutesofactiverestraintandoneadditionalfalsemountmaximizesspermcellnumbers.FinalpreparationsaremadetotheAVbetweenthesecondandthirdfalsemounts.ProperconstructionoftheAVisimportanttoavoiddamagingthebull'spenisandtoavoidstressingspermcells.

SuccessfulsemencollectionwithanAVdependsonthebullbeingcomfortablearoundpeople,andtheyneedtobetrainedtousetheAV.However,bullsarebiganddangerous,andpersonnelsafetyshouldbeemphasizedconstantly.Mostbullsinartificialinseminationcentershaveanoseringinstalledasavaluableandhumanemeansofphysicalcontrol.Bullsundergoingsemencollectionshouldbehalteredandoneshouldnevertieabullupbytheirnosering-ifstartled,thencanripitoutwhichisnotonlyquitetraumaticbutyieldsananimalthatmaybeexceptionallydifficulttocontrol.Duringcollection,thepersonhandlingtheAVmustremainawareofwheretheirfeetarerelativetothebull.Astheanimalejaculates,itiscommonforhimtojumpforward.Toavoidfootinjury,collectorsshouldwearbootswithsteeltoes.

Inartificialinseminationcenters,bullsaretypicallycollected2or3timesperweek,with2or3ejaculatespercollectionday.Thefollowingimagesdepictroutinesemencollectionfromabull.

Falsemountingtoarousebull

Anerectpenisindicatesarousal

CollectorreadywithAV

CollectordivertingpenistotheAV

SemenEvaluation

Semenshouldbeevaluatedgrosslyforabnormalappearance.Thepresenceofsmall"clots"orbloodcanindicatesuchconditionsasseminalvesiculitis.

Parameter

NormalValues

Ejaculatevolume

5ml（range1-15ml）

Spermconcentration

1200million/ml（range300-2500million/ml）

Totalspermperejaculate

Typically4-5billion

Progressivemotility

Greaterthan30%

Morphology

Greaterthan70%normal

SemenCollectionfromDogs

Semeniscollectedfromdogsforbreedingsoundnessexams,aswellasforartificialinsemination.Semencollectedfori