兽医产科学 第四章 妊娠课件

第四章

妊娠

ChapterFourGestation第一节妊娠期LessonOneGestationPeriod妊娠：受精卵在母畜子宫内附植直至分娩的过程叫妊娠。Gestation:Aprocessthatthezygoteenclosedplantindamuterusuntildeliverycalledgestation.妊娠期：最后一次配种直至分娩为止所经历的时间。GestationPeriod:Thetimeexperiencedfromthelastmatingtodelivery.一、动物的妊娠期

Partone.Gestationperiodoftheanimal牛：280天9.5个月水牛：307天10个月Bovine:280days9.5monthsbuffalo:307days10months马：340天11个月马怀骡：330天11个月Horse:340days11monthsmule:330days11months驴：360天12个月羊：150天5个月Neddy:360days12monthssheep:150days5months猪：114天3个月狗：62天2个月Swein:114days3monthsDog:62days2months猫：58天2个月兔：30天1个月Cat:58days2monthsHare:30days1months

怀孕期简易推算法Simplemethodsofestimatingpregnancy

牛：配种月份减3，配种日期加10Bovine:themattingmonthdecrease3,themattingdate羊：＝＝＝＝加5，＝＝＝＝减2

sheep:＝＝＝＝add5，＝＝＝＝decrease2猪：＝＝＝＝加4，＝＝＝＝减10

Swein:＝＝＝＝add4，＝＝＝＝decrease10马：＝＝＝＝减1，＝＝＝＝加10

Horse:＝＝＝＝decrease1，＝＝＝＝add10二、影响妊娠期的因素Parttwo.Influencefactorsofgestation（一）遗传因素SectionOne.Geneticfactor（二）胎儿数目和性别因素SectionTwo.Fetalnumberandgenderfactors

多胎怀胎数少时，妊娠期变长WhentheMultiplebirthsnumberisfew,pregnantgestationalgrowlonger单胎怀双胎，胎儿为雌性，青年母畜比老龄母畜妊娠期缩短。Ifthemonotocousanimalhadtwinsandthefetusisfemale,thegestationofyoungfemalelivestockisshorterthantheoldfemalelivestock’s.（三）营养水平及疾病因素SectionThree.Nutritionlevelanddiseasefactors

1.使妊娠期缩短的因素1.Factorsmakegestationshorten营养不良、慢性疾病、强应激。Malnutrition,chronicdiseasesandstrongstress.第二节母体的妊娠识别

LessonTwoMaternalrecognitionofpregnancy

一、妊娠识别Partone.Recognitionofpregnancy

胚胎与母体子宫从免疫学、细胞生物学、内分泌学等方面相互作用的过程。Aprocessofembryosandthematernaluterusinteractfromimmunology,cellbiologyandendocrinologyaspects.二、妊娠建立Parttwo.Establishofpregnancy

继妊娠识别后，母子产生信息和物质交换，妊娠得以维持的现象。Aphenomenonthattheinformationandmaterialexchangefrommotherandgenerateafterrecognitionofpregnancywhichmakesthepregnancymaintained.维持妊娠的主要激素是孕酮，来源于黄体和胎盘。Themainlyhormoneformaintainingthepregnancyisprogesterone,whichoriginatefromcorpusluteumandtheplacenta.三、妊娠识别与建立的时间Partthree.Thetimeofrecognitionandestablishofpregnancy

畜别妊娠识别妊娠建立genderoflivestockrecognitionofpregnancyestablishofpregnancy牛16-17d18-22dbovine16-17d18-22d羊12-13d16dsheep12-13d16d猪12d18dpig12d18d马14-16d36-38dhorse14-16d36-38d

四、动物妊娠识别机理PartFour.Mechanismofrecognitionofanimalpregnancy（一）反刍动物SectionOne.Ruminantanimals

滋养层蛋白-1（IFN-τ，interferon-τ)通过抑制PGs分泌、OT和E受体合成，促进黄体孕酮的分泌，维持妊娠。Trophoblasticprotein-1(IFN-τ,interferon-τ)byinhibitingsecretionofPGsandsynthesisofOTandEreceptor,promotingsecretionofcorpusluteumprogesteronetomaintainpregnancy.（二）猪SectionTwo.Pigs

滋养外胚层产生雌二醇和雌酮，转变成硫酸雌酮，使子宫内膜PGs合成减少，并阻止其进入子宫静脉，黄体得以维持。Nourishoutsidemesodermproduceoestrogenandfemaleketones,thenchangethemintosulfuricacidfemaleketones,makethesynthesisofendometrialPGsdecreasesandpreventsitintotheuterusvein,socorpusluteinismaintained.（三）马SectionThree.Horses与猪相似。Similartothepig.（四）灵长类SectionFour.Primates

囊胚的合胞体滋养层产生hCG，抑制溶黄物质的作用。ThesyncytialtrophoblastofblastosphereproducehCG,restrainthefunctionofthesubstancethatdissolveCorpusluteum.

hCG是在排卵后7-10天可以从血浆中测出，因此可用作早孕诊断。hCGcanbemeasuredfromplasmain7to10daysafterovulation,soitcanbeusedtodiagnosingearlypregnancies.一、胚胎早期发育

PartOne.Earlyembryonicdevelopment1．卵裂球：1.blastomere合子形成后若干天内连续进行的间接分裂，称为卵裂。这时的胚胎称卵裂球。（见图）cleavageisthecontinuationofindirectsplitinseveraldaysafterzygoteformed.theembryosinthistimenamedblastomere.(chart)合子一边沿输卵管下移，一边开始分裂。Azygotemovedownalongthetubal,andbegantosplit.2．桑椹胚：2.morula当卵子分裂为16－32个细胞时，细胞形成一团形，很象桑椹故称。但仍在透明带包围之中。Whenovumsplitsinto16-32cells,cellsformingagroupform,muchlikethemulberrythereforecallsmorula.Butstillinsurroundedbysheertape.3．囊胚：3.blastosphere当桑椹胚中央出现空泡时，细胞出现分化：Whenemptybubbleappearsinthecentralofmorula,cellsbegantodifferentiation:外围：较小的细胞，含有吞噬细胞，称之“滋养层”细胞，是以后形成胎衣的部分。Peripheral:smallercells,containingphagocyticcells,calledthe"trophoblastic"cells,whichisformedpartofafterbirthlateron.内团：较大的细胞，称“胚结”，是以后形成胚胎的原始部分。Withingroup:largercells,called"embryotie",whichisformedtheoriginalpartofembryoslateron.4．胚泡：4.germinalvesicle:囊胚的继续发育，内部的空泡充满液体，并不断增加，最后突破透明带，透明带消失，此时囊胚就变成了透明的泡状。Theblastospherecontinuedtodevelop,internalvacuolefilledwithfluid,andescalation,finallyitbreakthetransparentbelt,andtransparentbeltdisappear,nowblastospherebecomesatransparentbubbly.透明带消失后，胚泡仍在子宫中游离，通过吸收子宫乳中的营养而成活。野生动物由于野外条件不同，胚泡游离时间差异很大，决定了怀孕期长短。如水貂（37-91天）。afterTransparentbeltdisappeared,agerminalvesicleisstillfreeintheuterus,throughabsorbingnutritionfromthemilk-likeliquidinuterusandsurvive.Duetodifferentfieldconditionsforwildanimals,theirgerminalvesiclehasaverybigdifferenceinfreetime,thisdeterminesthelengthofpregnancy.Likeminks(37-91days).子宫乳成分：上皮细胞碎片、子宫腺分泌物、淋巴球、血球等。ingredientsofUterinemilk:debrisofepithelialcell,secretionofuterinegland,lymphocytes,bloodcell,etc.5．着床：5.nidation

胚泡在子宫中的位置固定下来，并开始和子宫内膜发生组织上的联系，称为着床。Thegerminalvesicle’spositionintheuteruscometostayandstartorganizationalcontactwithendometrial,calledthenidation.

胚泡形成初期，在子宫内呈游离状态，以后一方面由于泡腔内液体增多，胚泡变大，在子宫内的活动受到限制，与子宫上皮的接触变得密切，与母体建立供求关系；另一方面，子宫乳不能满足生长需要而附植下来。着床是一个渐进过程。Atearlyofthegerminalvesicleforming,itisthefreestateintheuterus,Laterononehandbecauseofbubblechamberliquidincreasedandblastocystsgreaten,theactivityisrestrictedintheuterus,andcontactcloselywithuterineepithelia,thenestablishtherelationsbetweensupplyanddemandwithmaternal;Ontheotherhand,uterinemilkcannotsatisfiedtheneedsofgrowthandattachplantdown.Thenidationisagradualprocess.动物胚胎着床时间

ThetimeofAnimalembryonidation牛：12－15天

Bovine:12-15days28－32天开始――到40－45天完成；Startat28-32days――accomplishto40-45days羊：12－20天

Sheep:12-20days14－16天开始――到28－35天完成；Startat14-16days――accomplishto28-35days猪：10－12天

Pig:10-12days14－16天开始――到25－26天完成；Startat14-16days――accomplishto25-26days马：60－65天

Horse:60-65days35－40天开始――到95－105天完成；Startat35-40days――accomplishto95-105days动物胚胎着床部位

ThepositionofAnimalembryonidation

子宫中最有利于发育的地方开始，如牛、羊，多在子宫角基部开始，向中部发展。因这里是子宫中动脉进入子宫的地方，血液供应最为丰富。Startattheplacemostfavorabletothedevelopmentintheuterus,suchasbovineandsheep,muchbeganinthebaseofthecornuauterianddevelopmenttothemiddlepart.Becausehereistheplacethattheuterinearteryentertotheuterus,bloodsupplyisthemostabundant.第四节胎膜和胎盘

LessonFourFetalmembraneandplacenta一、胎膜PartOne.Fetalmembrane叫胚胎外膜，又叫“胎衣”、“胞衣”、“衣胞”等。Callembryonicoutermembranes,alsocalled"afterbirth","secundina","amnia"etc.胎膜主要指羊膜、尿膜、绒毛膜，其构造在不同的动物有很大的差异。Fetalmembranemainlyreferstotheamnioticmembrane,urinarymembrane,chorion,itsconstructionhaveagreatdifferenceindifferentanimals.牛、羊胎膜囊Fetalmembranes

capsuleofbovineandsheep1．羊膜：是靠近胎儿的一层膜。呈透明状，包围胎儿形成羊膜腔；

1.Amnioticmembrane:Itisalayeroffilmnearthefetus.InAtransparentshape,surroundedthefetusandformedamnioticcavity;2．尿膜：可分内外两层，内层与羊膜相粘连，外层与绒膜相粘连；2.Urinarymembrane:It

canbedividedintotwolevelstheinsideandoutside,theinnerlayerconglutinatedwiththeamnioticmembrane,theouterlayerconglutinatedwiththechorion.3．绒毛膜：是胎膜的最外层，表面有绒毛，是形成胎盘的基础。3.Chorion:It

istheoutermostlayerofthefetalmembranes,thesurfaceisvillous,itisthebasisofformingtheplacenta.（一）卵黄囊：由内胚层、脏中胚层和滋养层构成。是胚胎发育早期提供营养的器官（起原始胎盘的作用）。SectionOne.Yolksac:Itisconstitutesbytheendoderm,visceralmesodermandtrophoblast.Itistheorgansthatprovidenutritioninearlyofembryonicdevelopment(roleasoriginalplacenta).（二）羊膜囊：羊膜由外胚层（滋养层）和体壁中胚层构成，出现在卵黄囊发育之后，一般在妊娠后13-16天形成。SectionTwo.Amnioticsac:Amnioticmembraneisconstitutesbyectoderm(trophoblastic)andthesomaticmesoderm,whichappearsaftertheyolk-sacdevelopment,andformscommonlyat13-16daysaftergestation.（三）尿膜囊：尿膜囊壁由中胚层的血管层覆盖在内胚层上构成的。尿膜囊是沿着脐带并靠近卵黄囊由后肠发育而来的一个外囊。SectionThree.Urinarymembranesac:Urinarymembranebursawallisconstitutesbymesodermalvascularlayercoveringtheendoderm.Urinarymembranesacisalongtheumbilicalcordandclosetotheyolk-sacanditisaoutsidesacthatdevelopsbyposteriorintestine.（四）绒毛膜囊：由外胚层和体壁中胚层构成。SectionFour.Chorionicsac:Itisconstitutesbyectodermandsomaticmesoderm.（五）脐带：由卵黄囊残迹和卵黄管和延伸而成，是连接胎儿和胎盘的纽带。SectionFive.Umbilicalcord:

Itisextendbytheremnantsofyolk-sacandyolktube,anditislinktoconnectthefetusandplacenta.二、胎水

PartTwo.Placentalfluid

是羊膜腔里的羊水和尿膜腔内的尿水总称。Itisagenerictermsofamnioticfluidintheamnioticcavityandurinaryfluidintheurinarymembranecavity.1．羊水1.Amnioticfluid来源：①羊膜柱状上皮细胞的分泌物；②胎儿唾液腺的分泌物。Sourc:①Thesecretionofcolumnarepithelialcellinamnioticmembrane;

②Thesecretionofthesalivaryglandsinthefetus.颜色：透明粘液状，后期稍带浊白色。Color:transparentmuciform,latewithslightlyturbidwhite.

羊水量：牛：5－6升马：3－7升羊:0.4－1.2升／只猪：40－150毫升／只Contentofamnioticfluid:Bovine:5-6litresHorse:3-7litersSheep:0.4-1.2litres/onlyPig:40-150milliliter/only成分：Ingredients:①混有脱落细毛，上皮，灰白色的胎饼（猪没有）。①Mixwithfalloffsoftfur,epithelium,gray-whiteembryocake(pigsdonothavethem).②含有微量激素，包括PRL、OT。②Containtracesofhormones,includingPRL,OT.③蛋白酶、淀粉酶、脂解酶。③Protease,amylase,lipidsolutionenzymes.④蛋白质、果糖、脂肪、盐类。④Protein,fructose,fat,salt.3．胎水的作用PartThree.Theeffectofplacentalfluid缓冲作用：使胎儿的身体各部位受压均匀，不致造成畸形。Bufferaction:makeeachpartsofthefetalbodypressureevenly,withoutcausingdeformity.缓和子宫外来压迫、撞击：也可以防止一部分胎盘、子宫壁及脐带受到胎儿压迫，而使血液供给障碍。Easeforeignoppressionandbumpofuterine:alsocanpreventpartofoppressionthatplacenta,uterinewallandumbilicalcordsufferfromfetus,andmakeobstaclesofthebloodsupply.羊水可以防止胎儿与周围组织的粘连。Amnioticfluidcanpreventtheadhesionofthefetusandthesurroundingtissue.分娩时，子宫壁的收缩，可将胎水推压到松软的子宫颈管，从而帮助扩大子宫颈管的作用。Whenparturited,theuterinewalliscontracted,anditwillpushpressplacentalfluidtoloosecervicalcanal,thushelpexpandtheeffectofcervicalcanal.天然润滑剂作用：以利胎儿产出。Effectofnaturallubricants:easytothefetaloutput.三、胎盘

PartThree.Placenta胎盘通常指尿膜绒毛膜和子宫粘膜发生联系所形成的构造。Placentausuallyreferstothestructurethatformedbythecontactsofurinarymembrane,chorinandtheuterinemucosa.分：胎儿胎盘――尿膜绒毛膜的绒毛部分母体胎盘――子宫粘膜部分Divideinto:fetalplacenta――thevillipartofurinarymembraneandchorion.Maternalplacenta――thepartofuterinemucosa

各自分布自己的血管到自己的胎盘部分，并不直接相通。Theydistributedtheirownbloodvesselstotheirownplacentalpart,andnotdirectlyinterlinked.（一）胎盘的分类

SectionOne.Classifyofplacenta1．按照形态分1.Accordingtotheform（1）弥散型胎盘(1)Diffuseplacenta

整个尿膜绒毛膜表面均覆盖有绒毛，绒毛伸入子宫内膜腺窝形成胎盘。电镜下,绒毛滋养层上皮细胞核成圆形,核仁大。粗面内质网发达，线粒体丰富。Thewholesurfaceofurinarymembraneandchorionarecoveredwithfluff,andthefluffstretchintoendometrialglandularnestandformedtheplacenta.Underelectronmicroscopy,fluffytrophoblasticepithelialcellsnucleusisroundnessandnucleoliisbig.Roughendoplasmicreticulumisdevelopedandmitochondriaisrich.

代表动物:猪、马、骆驼、鲸、海豚等。Representativeanimal:pigs,horses,camels,whales,dolphins,etc.特点：绒毛和腺窝联系虽是紧密的，但不牢固，绒毛在分离时，不牵连子宫粘膜。Features:Thoughthecontactofvilliandglandularnestisclosely,itisnotfirm.Whenthevilliisinseparation,itdon’tinvolveduterinemucosa.故：①较易发生流产，尤在怀孕早期；②分娩时，绒毛膜易脱离，如果胎儿排出缓慢，易发生窒息；③胎儿排出快，很少发生胎衣不下。So:①Itismoreeasilyhappentoabortespeciallyinearlypregnancy;②Whenparturited,chorioniseasilytobreakaway.Ifthefetusexpulsedslowly,itiseasilyhappentostifle;③Ifthefetusexpulsedfast,itseldomoccursretentionofafterbirth.（2）子叶型胎盘

(2)Cotyledonstypeplacenta

子宫粘膜上只有子宫阜部分与相应的绒毛发生联系。尿膜绒毛上的绒毛亦分别集中形成许多绒毛丛（形成胎儿子叶）。Itwasonlyuterinepartcontactswiththecorrespondingvilliontheuterinemucosa.Thevilliontheurinarymembranearealsoonthecentralizedandformsmanyvilliplexus(formedthefetalcotyledons).无论牛或羊，子叶之外的区域不与绒毛发生任何联系（联系则为病理状态）。Whetherbovineorsheep,theareasoutsidecotyledonshasnotanycontactwithvilli(Ifcontact,itispathologicalstatus).电镜下，绒毛表面细胞呈柱状/不规则形，核球形，核仁大，细胞游离面有微绒毛。巨细胞体积大，核仁明显，胞质丰富，可分泌绒毛促性腺激素。Underelectronmicroscopy,fluffysurfacecellsarecolumnarorirregularform,nuclearisspherical,nucleoliisbig,thefreesurfaceofthecellshavemicrovilli.Giantcellhasbigvolumeandnucleoliisobvious,cytoplasmisrich,itcansecretefluffygonadotropins.

代表动物：牛、羊属于此类。Representativeanimal:bovineandsheeparebelongtothiskind.子叶型胎盘的特点

Thecharacteristicsofthecotyledonstypeplacenta流产要比弥散型胎盘发生少；Ithaslessabortionthandiffuseplacenta;联系紧密，产程长也不会造成缺氧而发生窒息；Therelationisclosely,soifthestagesoflaborislong,itwon'tbehappennedtostiflecausedbyhypoxia;胎衣排出较慢，胎衣不下的比率较高。Afterbirthexpulsedslowly,sotheratiooftheretentionofafterbirthishigher.（3）带状胎盘

(3)Thezonaryplacenta

胎儿绒毛膜上的绒毛集中于绒毛膜中央在尿膜绒毛膜上形成环带状，子宫内膜上也形成相应的带母体胎盘。Thevilliofthefetalchorionhasfocusedonthecentraofthechorionandformedaringbandingintheurinarymembraneandchorion,anditalsoformedthecorrespondingbandingofthematernalplacentaontheendometria.特点：Characteristics:

分娩时母体胎盘组织脱落，子宫血管破裂，故有出血现象。Thehemorrhagewillappearbecausewhenparturition,theplacentatissueabscissfromthematrixandthevesseloftheuterinerupture.

代表动物：狗、猫。Representativeanimals:Thedogandcat.犬带状胎盘zonaryplacentaofdog（4）盘状胎盘

(4)Discoidplacenta绒毛膜上的绒毛在发育过程中逐渐集中，局限于一圆形区域。（绒毛直接侵入子宫内膜血窦中，毛上皮由细胞滋养层和合胞体滋养层构成）呈盘状，故称盘状胎盘。Thevillusonchorionconcentratetoonecircleareagradullyduringdevelopment.(Thevillusinvadeintoendometriumsinusoiddirectly,theepitheliumcomposedofcytotrophoblastandplasmoditrophoblast)

Itlookslikeadisk,thereforecalls

discoticplacenta.代表动物：见于啮齿类和灵长类动物，如兔、鼠和人。Representativeanimals:Therodentandprimatesuchasrabbits,mouse,andhuman.2.按母体血液和胎儿血液之间的组织层次分

2.Accordingtotheleveloforganizationbetweenthemotherandchild

（1）上皮绒毛膜型由子宫上皮细胞和绒毛膜滋养层细胞接触形成。物质交换经六道屏障:(1)

Epithelia-chorialtypeItisformedbythecontactofuterineepithelialcellandchoriontrophoblasts.Tofulfilledtheinterchangeofmaterial,theymustacrosssixbarriers:a.子宫内膜上皮endometrialepithelium.b.子宫内膜结缔组织endometrialconnetivetissuec.子宫血管内皮endometrialvascularepitheliumd.胎儿绒毛膜上皮fetuschorionicepitheliume.绒毛膜间充质（结缔组织）connectivetissuef.绒毛膜血管内皮chorionvascularendothelium代表动物：猪和马。Representativeanimals:Theswineandhorse.（2）上皮结缔绒毛膜型由子宫结缔组织（子宫上皮在妊娠4个月以后变性消失）和绒毛膜接触形成。物质交换只经过五道屏障.

(2)epithelialconnectiveChorionic-type

Itisformedbythecontactofuterusconnectivetissue(whichwilldisappearafter4monthgestation)andchorion.Itonlyneedfivebarrierstofinishtheinterchangeofmaterial.

代表动物：反刍动物。

Representativeanimals:Theruminant（3）内皮绒毛膜型由子宫血管内皮和绒毛接触形成。物质交换经过四道屏障.

(3)Theendotheliochorialtype

Itisformedbythecontactofendometrialvascularepitheliumandvillus.Theinterchangeofmaterialneedtoacrossfourbarriers.

代表动物：犬、猫。Representativeanimals:Thedogandcat（4）血液绒毛膜型胎儿绒毛直接侵入母体血液血池内形成。物质交换只经过三道屏障.(4)Bloodepithelia-chorialtype

Fetalcotyledoninvadeintomatrixblooddirectly.Theinterchangeofmaterialonlyneedtoacrossthreebarriers.代表动物：啮齿类和灵长类。Representativeanimals:Therodentandprimate（二）胎盘的生理作用

SectionTwo.Thephysiologicalactionofplacenta胎盘担负着胎儿的消化、呼吸和排泄器官的作用，而且还有内分泌机能。Theplacentashoulderthefunctionofdigestion,breathing,excretionandalsothatofincretion.1．胎盘的隔（屏）障作用：

1.Thebarrierfunctionoftheplacenta:

母子之间物质交换，通过胎盘，具有选择作用。即除了单纯性弥散作用外，还能加速弥散或主动转运作用。Withthehelpoftheplacenta,motherandchildcanfulfilltheinterchangeofmaterial.Theinterchangeofmaterialisselectivebecauseithasnotonlythediffusionfunctionbutalsotheactivetransportfunction.①简单的物质可以直接通过胎盘：水、Nacl、Cu、I、VB和VC等；①

Thesimplerkindofmattercantransittheplacentadirectly:suchaswater,NaCl,Cu,I,VB,Vcandsoon;②某些物质不能直接通过，须经过生化改造后才能通过：②

Thefollowingmaterial

cannottransit

theplacentadirectlywithoutthebiochemicalalterations:脂肪→脂肪酸＋甘油蛋白质→氨基酸葡萄糖（母体主要糖类）→胎盘转化为果糖（胎儿血糖的70－80％）。Lipid→Fattyacid+GlycerinProtein→AminoacidGlucose(mainlythecarbohydrateinmatrix)→transformintofructosethroughplacenta(70－80％bloodsugaroffetus)③逆渗透梯度通过胎盘：母体血液中的浓度明显低于胎儿血液。③

Transittheplacentareversetheosmosisgradient:Theconcentrationofmaterialinbloodofmatrixismuchlowerthanthatoffetus.如钙、磷，如果饲料中含量太低，母体骨髓中的钙、磷即受损耗，易产生孕畜截瘫；Suchascalciumandphosphorus.Thematrixiseasytohavetheparaplegiabecausethecalciumandphosphorusiseasytobelosedwhenthereisnotenoughcalciumandphosphorusinforage.蛋白质：通过分解为氨基酸，后逆浓度梯度进入胎盘Protein:Afterbeingresolvedintoaminoacid,itransittheplacentareversetheosmosisgradient.④不能通过屏障的：VA、VD、VE等脂溶性维生素。④Thefollowingfat-solublevitaminsuchasVA,VD,VEis

unabletotransittheplacenta.⑤氧气易通过胎盘进入胎儿，二氧化碳则相反易通过胎盘排出；因为，胎盘pH较低，母体氧化血红蛋白进入胎盘很易离析，胎儿血红蛋白对氧有更大的亲和力。胎儿血液与二氧化碳的亲和力要比母体血液低。⑤

Oxygencantransittheplacentaintofetuseasily,carbondioxide,onthecontrary,easilyexcretedthroughtheplacenta.ItisbecausethatthelowerpHinplacentamadehemoglobineasytodissociatewhentheytransitintotheplacenta,thefetalhemoglobinismoretendtobondtheoxygenbuthaveloweraffinitywithcarbondioxide.⑥某些（对胎儿发育有影响）的物质也可直接通过：乙醚、氯仿、酒精、樟脑、水杨酸、松节油、阿托品、毛果芸香碱、番木氅酊、砷等。⑥Thefollowingmaterial(whichwillinfluencethedevelopmentoffetus)such

asaether,chloroform,alcohol,camphor,BHA,turpentineoil,atropin,picarpineandarsenic

cantransittheplacentadirectly.⑦细菌不能通过，病毒可通过：但当胎盘病变时，细菌也能通过；⑦Theviruscantransittheplacentawhilethebacteriacan’t:Butwhenplacentaispathologicalchanges,thebacteriacanalsotransittheplacenta.⑧部分抗体可通过胎盘⑧Aportionofantibodycantransittheplacenta:豚鼠和兔子抗体可通过胎盘传递给胎儿；Theantibodyofcaviaprocellusandrabbitcantransittheplacentaintofetus.家畜只能通过初乳被动免疫；Thelivestockcanonlytransittheantibodythroughforemilk.狗、猫、大鼠、小鼠通过胎盘接受少量，大部分则来自于初乳。Thedog,cat,rat,mousecanonlyacceptalittleantibodythroughplacenta,mostofantibodycomefromforemilk.抗体能否通过胎盘与Ig分子量的大小密切相关。WhethertheantibodycantransittheplacentadependsonthemolecularweightofIg.2．内分泌作用2.Thefunctionofendocrine胎盘为一暂时性的内分泌器官，能分泌雌二醇、孕酮（马、羊）、PMSG、HCG（人）、PRL等。Placentaisatemporalendocrinalorganwhichcansecreteestradiol,progesterone(thehorseandsheep),PMSG,HCG(human),PRLandsoon.3．酶促、酶解作用3.Thecatalysisandzymolysisoftheplacenta

参与胎盘的代谢作用，大体可分为：氧化还原酶、转移酶、水解酶、溶解酶、异构化酶五类。Theoxido-reductase,transferase,hydrolase,cytaseandallomeraseparticipateinthemetabolismofplacenta.作用：分解物质、合成物质、输送物质、合成激素。Function:Composeanddecomposethesubstance,transportmaterial,synthetizehormone.四、脐带

Part4.Umbilicalcord脐带是连接胎儿和胎盘的纽带，其外膜为羊膜，形成羊膜鞘，内含：脐血管、脐尿管、卵黄囊遗迹等。Theumbilicalcordistheligamentthatconnectthefetusandplacenta,thetunicaexternaisamnioticmembrane,whichformtheamnioticsheath.Thereareumbilicalvessels,urachusandtheremainsoftheyolksacinumbilicalcord.长度：牛：30－40cm羊：7-12cm猪：20-25cmLength:Bovine:30to40cmSheep:7to12cmSwine:20to12cm血管：Vessel:牛、羊：动脉两条,静脉两条，但进入脐孔后合并为一条。Thecattleandsheep:Theyhavetwoarteriesandtwoveins,buttwoarteriesandtwoveinsconnectedintooneafterenteringthenavel.马、猪：动脉两条，静脉一条Thehorseandswine:havetwoarteriesandonevein.注：牛羊脐孔组织与血管之间联系疏松，故生下后，脐带不能撕太短，否则，易缩至腹腔，造成内出血.Notes:Youcan’tteartheumbilicalcordtwoshortwhenthefetusarebornbecausethenaveltissuehaslooseconnectionwithvessel,orelseitwillretractintoenterocoelia,whichwillcauseinternalhemorrhage.五、牛多胎囊关系

Part5.Thereasonofmultiplefoetalsac牛：怀双胎时，绝大多数是二胎囊接触端上的尿膜绒毛膜合起来，血管吻合，故：Cow:Whenthecowarebigeminalpregnancy,mainlythecontactjawoftwofoetalsacsfilmthechorioallantois,thevascularanastomosis.So:异卵双胎：如果双胎性别不同，雌牛犊则无生生殖能力（90－95％）。公犊虽发育正常，亦不能种用。原因：雄胎睾丸发育早，雄激素抑制雌胎卵巢发育。Dizygotictwins:

90－95％offemalcalfaresterileifthetwinsaredifferenceingender.Thebullcalfarealsosterilethoughtheyarezoonal.Becausethetesticleofthebullcalfdevelopearly,itcansecreteandrogentosuppressthedevelopmentofthefemalcalf.同卵双胎：一个受精卵，在发育过程中，形成两个内细胞团，各自发育成完整个体。Identicaltwins:Inthedevelopment,oneoospermdevelopintotwoinnercellmass.Thattwoinnercellmassgrowintotwozooid.第五节怀孕时母体的变化

LessonFiveChangesinthematrixduringpregnancy可以作为怀孕诊断参考，加强饲养管理的依据。Changesinthematrixduringpregnancycanbeusedasdiagnosticreferenceofpregnancyandstrengthenthebasisoffeedingandmanagement.一、生殖器官的变化

PartOne.

Changesinreproductiveorgans1．卵巢：1.Ovarian:形成黄体：一是发生怀孕，黄体便持续下去，直到分娩（或流产）前几天。即为妊娠黄体。Theformationofthecorpusluteum:Whenpregnancy,thecorpusluteumwillcontinuetobecorpusluteumverumuntilthebirth(orabortion)afewdaysago.

黄体往往比卵泡大，使卵巢体积增大。Usually,thecorpusluteumislargerthanfollicle,whichwillincreasethevolumeoftheovarian.2．子宫

2.Theuterus体积：增大首先是由孕角的子宫体开始，以后胎膜伸入空角，故“空角”实不空。但孕角的增大总要比空角大得多，两者始终不对称（多胎动物例外）。Volume:Theincreasestartedfromtheuterusofpregnanthorn,afterthat,theembryolemmainsertintothecorner.Sothe“emptyhorn"isreallynotempty.Theyareasymmetric,becausetotalincreaseofpregnanthornismuchgreaterthantheemptyhorn(exceptmultiparousanimal).在怀孕前半期――由于胎儿尚小，主要是子宫肌纤维肥大、增长，使子宫壁增厚。Inthefirsthalfofpregnancy,sincethefetusisstillsmall,thethickoftheuterinewallaremainlydepondedonthehypertrophyandincreaseofuterinemusclefiber.在怀孕后半期――由于胎儿迅速增大，使子宫壁扩张，故子宫壁变薄。羊尤为明显，故羊怀孕时子宫破裂病例较多。Inthelatterhalfofpregnancy,theuterinewallbecomesthinnerbecausetheuterinewallexpansionwiththerapidlyincreaseofthefetus.Especiallysheep,therearemorecasesoftheuterineruptureduringpregnancy.3．血管

3.vessel怀孕后，由于供应子宫的血流量增加，故血管加粗，主要表现子宫中动脉、子宫后动脉。出现明显怀孕脉搏。Afterpregnant,thevessel(mailythemid-uterinearteryandarterybehindtheuterine)willbecoarsenbecausethesupplyofbloodtouterinewillincrease.Thepregnancypulsewillappearclearly.牛的怀孕脉搏在5个月时就很明显，这对诊断死胎有重要价值。Thepregnantpulseofthecowisclearinfivemonths,itisvaluableforthediagnosisofstillbirth.二、全身变化

PartTwo.Systemicchange初期：新陈代谢变得旺盛，食欲增加，消化力增加，体膘变好。initialstage:

metabolicbecomestrong,foodappetite,digestionandweightincrease.后期：胎儿发育快，牛胎儿体重的60％是在最后二个月生长的。这时母畜营养的摄入不能满足迅速发育的胎儿的需要，尽管食欲仍很好，或更旺盛，但变得消瘦。Laterstage:Thefetusgrowrapidly,60%weightofthebovinefetalgrowinthelasttwomonth.Atthistime,thenutritionalintakeofmatrixcannotmeettherapiddevelopingoffetus.Thus,thematrixbecomethininspiteofgoodappetiteorevenmore.1．矿物质代谢――主要钙、磷逆渗透梯度通过胎盘，胎儿需求量大，因此，如果补充不足，容易引起孕畜截瘫。1.Mineralmetabolism:

Calciumandphosphorus,whichareneededtofetus,throughtheplacentainreverseosmosisgradient.Ifinsufficent,itiseasytocausetheparaplegiaofthematrix.2．心血管系统―心脏负担增加出现心理性肥大，尤其左心室。怀孕后期，由于巨大子宫压迫腹部及后肢静脉，所以出现腹下、乳房、后肢的水肿。2.Cardiovascularsystem:Theincreasedburdenofthecardiacleadtopsychologicalhypertrophy,especiallytheventriculussinister.Inlatepregnancy,thematrixappeartohavetheoedemainhypogastric,breast,hindlimbwhichbecausethebellyandhindlimbveinsufferedthegreatpressurefromtheuterus.3．大小便变化――子宫增大，胃肠容积减少，排粪、排尿次数增加，数量减少。3.Changesinurine:

Hysterauxesis,thevolumeofthestomachandintestinedecrease.Thefrequencyofthedefecationandurinationincreased,butthequantitydecrease.4．呼吸变化――横膈膜受到压迫，腹压增大，由腹式呼吸变为胸式呼吸。4.Changesinbreathing:Thediaphragmwasoppressed,abdominalpressureincrease,itchangesfromabdominalrespirationtothoracicrespiration.5．行为变化――稳重、谨慎、容易疲劳、出汗。5.Changesinbehavior:Steady,cautious,exhausteasilly,perspiration.三、妊娠诊断

PartThree.Cyesiognosis（一）临床诊断法SectionOne.Clinicaldiagnostics1.问诊：1.Inquiry:配种次数、最后一次配后是否返情、配后一定时期母畜食欲是否改善。numberofserviceperconception,whetheritreturntooestrusafterthelasttimeofconception.Whetherthefoodappetiteofthematriximproveaftertheconception.2.视诊：2.Inspection（1）外表观察:腹部不对称，马多为左侧，牛羊多为右侧，猪部下垂。

(1)Exteriorinspection:Theabdomenisdissymmetric,usually,theleftsideofthehorseisdissymmetric,flocksandherdsisrightside,swineisbottom.（2）阴道视诊:检查阴道粘膜色泽、粘液性状和子宫颈形状及其粘液的变化。如马未孕时阴道粘膜为淡粉红色，怀孕3个月变为苍白。羊当刚打开阴道时粘膜为白色并迅速变为红色者，为怀孕症状。(2)Vaginalexamination:Includingthecolorofthevaginamucosa,thecharacterandthechangesofthemucusandtheshapeofcervix.Whenthehorsearenotpregnant,thevaginamucosaispink,butitwillbepaleafterpregnantforthreemonth.Thepregnancysymptomsofthesheepisthatthecolorofthevaginachangefromwhitetopinkwhenitisopen.3.外部触诊：3.Externalpalpation:马：用手掌连续推动左（右）腹壁最突出的地方、乳房稍前部。怀孕8-9月以后，可以感到腹腔内有硬块（胎儿）。Thehorse:Withtheleft(right)palm,keeppushingthemostprominentplaceoftheabdomen,alittlefrontfromthebreast,youcanfeelthatthereisalump(fetus)inenterocoeliawhenthehorsearepregnantfor8to9month.牛：用弯曲的手指节或拳触诊右侧膝皱褶的前方，怀孕7-8月以上能触到胎儿。The

cow:Palpatingthefrontoftheceaseofthe