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Andrology of the Bull

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Andrology of the Bull AndrologyAndrology ofof thethe BullBull Spermatogenesis/Spermatogenesis/ Hormones/Hormones/ BreedingBreeding SoundnessSoundness Spermatogenesis:Spermatogenesis: TheThe processprocess byby whichwhich stemstem cellscells developdevelop intointo maturemature spermatozoa.spermatozoa. ThereThere areare threethree phases:phases: (1)(1) SpermatocytogenesisSpermatocytogenesis (Mitosis)(Mitosis) (2)(2) MeiosisMeiosis (3)(3) SpermiogenesisSpermiogenesis Spermatogonium 1/ SPERMATOCYTOGENESIS 2/ MEIOSIS Spermatids 3/ SPERMIOGENESIS Spermatozoa Epididymal Maturation Spermatogonium Mitosis Primary Spermatocyte 1st Meiosis Secondary Spermatocyte 2nd Meiosis Spermatids Spermatozoa Epididymal Maturation Spermatogonium 15 Days Primary Spermatocyte 15 days Secondary Spermatocyte 1 - 2 Days Spermatids 15 days Spermatozoa 21 days Epididymal Maturation Spermatogonium 4 15 Days Primary Spermatocyte 15 days 1 Secondary Spermatocyte 1 - 2 Days Spermatids 2 15 days Spermatozoa 3 21 days Epididymal Maturation Sensitivity to Disruption- 1: Most sensitive/ 4: Least sensitive BloodBlood--TestesTestes BarrierBarrier Tight junction between adjacent Sertoli cells. Large molecules cannot pass from the blood into the lumen of a seminiferous tubule The spermatogonia are in the basal compartment (deep to the level of the tight junctions) More mature forms are in the adluminal compartment. The function of the blood- testis barrier may be to prevent an auto-immune reaction. LeydigLeydig CellsCells Æ Stimulated by LH ÆÆ SecreteSecrete TESTOSTERONE Æ FSH increases number of LH receptors SertoliSertoli CellsCells Æ Stimulated by FSH Æ “Nurse” cells of the testes ÆÆ SecreteSecrete ESTRADIOL andand INHIBIN Æ -ve Feedback Æ Supports Spermatogenesis ÆForms Blood- Testes Barrier Æ Requires FSH and testosterone Æ Produces Androgen-binding protein (ABP) TestosteroneTestosterone TargetTarget CellsCells Æ Cells of Spermatogenesis Æ Accessory Sex Glands Æ Genitalia Æ Anabolic effect (muscles) MaintainMaintain TargetTarget ConcentrationsConcentrations Æ -ve Feedback: Estradiol & inhibin Æ Autoregulation Æ -ve feedback Maintained in Testes: Æ ABP binding testosterone Æ Pampiniform Plexus A- Testicle B- Epididymis (head) C- Epididymis (body) D- Epididymis (tail) E- Ductus deferens F- Mesorchium G- Ampulla H- Vesicular Gland I- Prostate K- Urethra L- Bulbourethral gll M- Bulbospongiosus N- Crus penis O- Ischiocavenosus P- Penis R- Glans Penis S- Retractor penis T- Urinary bladder U- Pelvic symphysis V- Rectum AA-- HeadHead ofof EpididymisEpididymis BB-- BodyBody ofof EpididymisEpididymis CC-- TailTail ofof EpididymisEpididymis DD-- DuctusDuctus DeferensDeferens EE-- EpididymalEpididymal LigamentLigament FF-- MesorchiumMesorchium GG-- TesticularTesticular bursabursa FunctionFunction ofof thethe EpididymisEpididymis 1/1/ ConcentrationConcentration ofof SpermSperm (head(head andand body)body)-- ÆÆ AbsorptionAbsorption ofof excessexcess fluidfluid ÆÆ IncreaseIncrease storagestorage capacitycapacity 2/2/ MaturationMaturation ofof SpermatozoaSpermatozoa ÆÆ ChemicalChemical changeschanges withinwithin spermsperm 3/3/ StorageStorage ofof SpermSperm (tail)(tail) ÆÆ SpermSperm cancan ageage inin epidydimisepidydimis BreedingBreeding SoundnessSoundness ExaminationExamination 1/1/ HistoryHistory 2/2/ PhysicalPhysical examinationexamination ÆÆ GeneralGeneral ExaminationExamination ÆÆ GenitalGenital ExaminationExamination ÆÆ ExternalExternal GenitaliaGenitalia ÆÆ InternalInternal GenitaliaGenitalia 3/3/ SemenSemen EvaluationEvaluation HistoryHistory AgeAge ofof firstfirst serviceservice DateDate ofof lastlast serviceservice PreviousPrevious ExaminationsExaminations DiseaseDisease && VaccinationVaccination HistoryHistory TransportTransport BreedingBreeding systemsystem-- RatioRatio ofof bullsbulls toto cowscows HerdHerd healthhealth history/history/ ConceptionConception ratesrates GeneralGeneral PhysicalPhysical ExaminationExamination GeneralGeneral ConformationConformation DefectsDefects EyesightEyesight MasticationMastication problemsproblems LocomotoryLocomotory problemsproblems HereditaryHereditary DefectsDefects BodyBody ConditionCondition ExternalExternal GenitaliaGenitalia ScrotumScrotum TesticlesTesticles SpermaticSpermatic cordcord EpididymidesEpididymides SheathSheath PenisPenis ScrotalScrotal CircumferenceCircumference ScrotalScrotal CircumferenceCircumference InternalInternal genitaliagenitalia Rectal Examination: Prostate Gland (8) Seminal vesicles (7) Cowper’s Gland (10) Ampulla (6) Æ Size Æ Symmetry Æ Width Æ Consistency Æ Pain on palpation Inguinal Rings SemenSemen CollectionCollection SemenSemen EvaluationEvaluation EvaluateEvaluate semensemen qualityquality ÆÆ volume,volume, ÆÆ color,color, ÆÆ consistency,consistency, ÆÆ massmass motilitymotility (overall(overall movementmovement observedobserved inin thethe microscopy,microscopy, "waves"),"waves"), ÆÆ individualindividual motilitymotility ofof spermsperm cellscells ÆÆ semensemen morphologymorphology (that(that is:is: normal/abnormalnormal/abnormal lookinglooking cells)cells) NormalNormal ParametersParameters ParameterParameter NormalNormal ValuesValues Ejaculate volume 5 ml (range 1-15 ml) Sperm concentration 1200 million/ml (300-2500 million/ml) Total sperm per ejaculate Typically 4-5 billion Progressive motility Greater than 30% Morphology Greater than 70% normal http://www.vivo.colostate.edu/hbooks/pathphys/reprod/semeneval/bull.html ColorColor Opacity:- Indication of concentration Color--acceptable color ranges from milky to creamy (Note: This indicates sperm per cubic millimeter of 500,000 or above. Other colors indicating less than 500,000 sperm/cu mm would be opalescent (cloudy) to watery.) Mass/Mass/ IndividualIndividual MotilityMotility Bulls: > 30% progressively motile sperm Adversely affected by; Æ heat Æ cold Æ residue on collection equipment Æ wrong pH or osmolality Æ Sexual inactivity Live/Live/ DeadDead StainingStaining Live/Live/ DeadDead StainingStaining MajorMajor defectsdefects AA--ProximalProximal CytoplasmicCytoplasmic DropletDroplet BB-- PyriformPyriform headsheads CC-- Folded/Folded/ CoiledCoiled TailsTails DD-- MiddleMiddle piecepiece DefectsDefects EE-- MaldevelopedMaldeveloped FF-- CratersCraters MinorMinor defectsdefects AA-- DistalDistal cytoplasmiccytoplasmic dropletsdroplets BB-- TaillessTailless normalnormal headsheads CC-- SimpleSimple bend,bend, terminallyterminally coiledcoiled tailtail DD-- narrow,narrow, smallsmall oror giantgiant headsheads EE-- AbaxialAbaxial implantationimplantation FF-- AbnormalAbnormal AcrosomesAcrosomes .
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