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68 Cards in this Set
- Front
- Back
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Methods of obtaining semen samples
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-artificial vagina
-manual stimulation into receptacle -electroejaculation |
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Artificial vagina
-used for what animals |
-stallion
-trained bull |
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Artificial vagina
-interior compartment |
-filled with warm water because the stallion is a temperature sensitive ejaculator
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Artificial vagina
-provides what |
-temperature stimulation
-pressure stimulation |
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Manual stimulation into a receptacle
-animals |
-dog
-boar |
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Manual stimulation into a receptacle is for what kind of ejaculator
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-pressure sensitive
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Electroejaculation
-animals |
-bull
-billy/ram (sedated) -wildlife 9anesthetized) |
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Things that corrupt collection of a representative semen sample
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-first part of the sperm rich fraction in the epididymis with sexual rest may be abnormal
-fecal contamination, urine, water, soap, and blood can adversely effect motility and make it difficult to do a good sperm morphological exam -high and low environmental temperatures can affect sperm motiility |
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Are the volume of ejaculate, sperm density, and gross characteristics good predictors of fertility?
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-NO
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Methods of assessing sperm motility
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-gross motility
-individual motility |
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Semen motility
-minimum recommended motility |
-30% or fair
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Sperm motility
-very good rating (gross, individual) |
-gross: rapid swirling
-individual: >70% |
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Sperm motility
-good rating (gross, individual) |
-gross: slower swirling
-individual: 50-69% |
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Sperm motility
-fair rating (gross, individual) |
-gross: generalized oscillation
-individual: 30-49% |
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Sperm motility
-Poor rating (gross, individual) |
-gross: sporadic ascillation
-individual: <30% |
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Does sporadic oscillating semen mean there is a problem?
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-Not necessarily
-sample can be very dilute and would need to be re-evaluated |
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Why should latex gloves not be worn when handling semen?
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-latex is spermicidal
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Warming plate should be used for:
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-slides
-stains -coverslips -semen *keep warm at all times and prevent cold shock |
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Examination of gross motility
-procedure |
-place drop of semen on a warmed slide and observe under 100x (low) magnification
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Examination of individual motility
-procedure |
-assess under bright-field or phase-contrast microscopy at 400x
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Individual motility examples
-dilution |
-sodium citrate
or -skim milk based semen extender or -physiological sterile saline (if exam done promptly) |
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Differential counts of normal and abnormal sperm are generally assessed by:
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-phase-contrast microscopy using samples fixed in formalin-buffered-saline or PBS-gulteraldehyde
-bright field microscopy of stained smears |
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Morphological exam
-magnification |
-1000x
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Evaluation of semen morphology
-stains |
-nigrosin-eosin
-williams stain -modified giemsa -DifQuik -India ink |
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Morphologic evaluation
-how to stain |
-1 drop semen mixed with 1 drop nigrosin-eosin and the mixture is spread over the surface of a glass slide and allowed to dry
-vary smear thickness |
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Morphological evaluation
-requirement for bull to pass BSE |
-al least 100 random sperm need to be observed and at least 70% of observed cells need to be normal
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If a particular semen sample has a high number of abnormalities, what may be necessary?
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-counting 500 or more sperm
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Sperm
-viability stain |
-Eosin or Propidium iodide
-relies on a permeable plasma membrane to define a non-viable sperm |
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Why is a viability stain not very well correlated with fertility?
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-we have no idea how viable the unstained sperm are, we just know that they are viable
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Rather than different insults causing different morphological abnormalities, ______________
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a number of different insults cause stress which results in specific abnormalities to germ cells in specific phases of development/maturation
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Inherited sperm abnormalities
-why rarely seen |
-cause infertility
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Inherited sperm abnormalities
-effects |
-knobbed defect
-dag defect -tail stump defect -azoospermia/oligospermia -decapitated defect -rolling head/nuclear crest/giant head syndrome |
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Sperm cell morphological classification systems
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-based on origin (testicular, extra-testicular)
-based on significance (major/minor) -based on functional contribution to fertility (compensable/uncompensable) |
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Sperm Morphology based on origin
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Primary abnormalities
-arise during spermatogenesis in seminiferous tubules due to pathological processes in the seminiferous epithelium -abnormal head, abnormal midpiece, proximal cytoplasmic droplet, etc. Seconday abnormalities: -arise after sperm cells had left testis such as abnormal epididymal function -bent tails, coiled tails, etc. |
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Sperm morphology based on significance
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Major abnormailites
-correlated to impaired fertility Minor abnormalities -minor importance *difficult to figure out |
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Sperm morphology based on functional contribution to infertility
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Compensable abnormalities
-defects that cause an affected sperm cell to fail to reach and fertilize the ovum -sperm can induce zona reaction -increasing the dose of sperm (A.I.) will result in more total normal sperm and improved fertility -ex) tail problem that precludes forward motility Uncompensable abnormalities -defects that don't prevent a sperm from reaching the ovum but prevent normal development of the embryo -sperm can't induce zona reaction -increasing sperm dose A.I. will result in same percentage of abnormal sperm and hence same fertility |
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What is it?
-describe |
-Fertility Dose-Response Curve
-Fertility plateaus at 5-10 million sperm cells -Bull C has compensable sperm abnormalities -Bull D has non-compensable traits |
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Describe abnormality
-type of abnormality |
Strongly folded midpiece
-Major/Primary abnormality |
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Describe abnormality
-type of abnormailty |
Coiled tail
-Minor/Secondary abnormality |
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Describe abnormality
-Type of abnormality |
Detached head
-Minor/Secondary abnormality *not uncommon to find in a normal semen sample |
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Describe abnormality
-type of abnormality |
Distal droplet
-Minor/Secondary abnormality *not abnormal |
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Describe abnormality
-type of abnormality |
Elongated head
-Major/Primary abnormality |
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Describe abnormality
-type of abnormality |
Misshapen head
-Major/Primary abnormality |
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Describe abnormality
-Type of abnormality |
Proximal droplet
-Major/Primary abnormality |
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Describe abnormality
-type of abnormality |
Pyriform head and bend midpiece
-Major/Primary abnormality |
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Describe abnormality
-Type of abnormality |
Reversed tail
-Minor/secondary abnormality *probably human error from cold shock if a C-shaped bend is present in the tail |
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Describe abnormality
-Type of abnormality |
Medusa cell
-unknown |
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Presence of spermatogenic epithelial cells (spheroids) in the semen suggests what?
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-poor health of the seminiferous tubules
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Breeding soundness exam
-limitations |
-only reflects breeding soundness on the day tested
-sperm cells seen today were begun weeks ago -does not predict ability to cause conception in the future -better for identifying subfertile males than highly fertile females |
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Breeding soundness exam
- strengths |
-guarantees that sub-fertile males are not used for breeding
-removes subfertile males from the genetics of the herd and breed -over time herd and breed fertility are increased |
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Breeding soundness exam
-interpretation |
-good at IDing poor performing males
-bell shaped curve does not allow us to predict how males that pass BSE will perform |
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Ultrasound
-use |
-evaluate/detect fibrosis
-soft areas -spermatoceles |
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Thermography
-use |
-check thermoregulation of testes
-if scrotal surface temp is high or displays little decrease as one moves from the top to the bottom of the scrotum there are: more abnormal sperm, fewer pregnancies |
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Computer Aided Sperm Analysis (CASA)
-equipment |
-software that utilize video capture from microscope video recorded
-phase contrast or darkfield microscope |
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Computer Aided Sperm analysis
-motility can be altered by |
-dilution of semen
-image settings -semen viscosity and ionic composition -temp extremes |
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Evaluation of frozen semen
-preferred values |
> 50% linear motility (slower motility)
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Evaluation of frozen sperm
-when to evaluate |
-thaw
-2 hours post thaw |
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If AI uses fewer sperm cells and many are damages, how do we get cows/mares/b!tches pregnant?
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-deposit semen in uterus rather than vagina
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Evaluation of sperm quality has arisen because:
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-our desire to predict fertility
*goal has not been achieved |
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Role for in vitro evaluation of sperm quality
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-predicts male will be less fertile than average males
-can predict that a given sample has a high probability of providing similar to that he has achieved in the past (if males with known fertility had semen characterized in the past) |
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What can't be done with in vitro evaluation of sperm quality?
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-can't take a male with unknown fertility and predict that his fertility will be greater than the mean for fertile males
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CASA
-measured characteristics |
-Percent motility
-Velocity curvilinear -Velocity average path -Velocity straight line -Linearity -Wobble -Progression |
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Attributes of sperm essential for fertility
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-acceptable morphology
-maturation of spermatozoa within the proximal epididymis -maturation of membrane lipids -maturation of membrane proteins -activation of integral enzymes associated with fertilization -upon exposure to the micro-environment of the oocyte -upon exposure to the cytopplasm of the oocyte |
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Frozen semen
-chemical and physiological shanges that occur during freezing and thawing |
-partial dehydration
-cryprotectant penetration of cells -reorganization of membrane lipids and proteins -exposure to high salt concentrations -exposure to inter and intracellular ice crystals |
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Evaluation of frozen semen
-purpose of evaluation post-thaw |
-evaluate degree of sperm damage inflicted by crypreservation feature
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Diadem Crater Defect
-induced by |
-pyrexia
-ethylene dibromide -sulfasalazine -corticosteroids -low testosterone -viruses |
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Midpiece defect
-induced by |
-Gossypol
-Ethylene dibromide -Genetics -Respiratory disease |
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Gossypol
-effects on bull repro tract |
-degeneration and reduction of spermatogenesis
-damage to the basement membrane of spermatogenic tubules -increase in abnormal sperm |
