Therio - The Stallion 2

drraythe's version from 2017-09-10 04:05

BSE Semen Evaluation

Question Answer
Once you get the semen sample, what are the 2 things you must do to properly care & preserve it?(1) REMOVE THE GEL FRACTION
Why do you want to remove the gel fraction of the semen? What makes the gel fraction?Gel is produced by the vesicular glands & tends to trap the spermatozoa
What makes semen so cold sensitive? What do you do to make it less sensitive?Spermatozoa are mixed w/ seminal plasma from the accessory sex glands in the horse → This makes the spermatozoa very sensitive to temperature changes. So you must Always keep equine semen at 37°C (warming table, incubator, good insulation) & you Decrease the effect of the seminal plasma by adding semen extender: provides protection against temperature changes, energy, buffers (pH changes).
**What temp must horse semen be kept at?Always keep equine semen at 37°C (98.6°F) (warming table, incubator, good insulation)
What are you looking for w/ the macroscopic examination of semen?Volume, color, consistency, pH
What are you looking for w/ the microscopic exam of semen?Concentration
Foreign cells
What color do you want semen to be? What consistency?Color: Ideally want ivory - white (Check for blood (red or brown) or urine)
Consistency: Don’t want it to appear too watery
**What pH should semen be?7.2-7.9
What might it mean if the semen was more acidic? Basic?More acidic = possible urine contamination
More alkaline = possible leukocytosis
What are some (3) ways to gauge the conc of the semen?(1) Electronic counter
(2) CASA system (Computer Assisted Sperm Analysis)
(3) Manually = hemocytometer
What is the important parameter in quality control, & what do you need to be careful about to make sure you don't mess up?Motility is the most important parameter. BEWARE OF COLD SHOCK!!! KEEP EVERYTHING WARM!! This will mess up your results
How do you make an OBjective & a SUBjective eval of semen motility?Subjective assessment using light microscope or phase contrast (make educated guess if more (or less) than 50% are moving in somewhat forward direction → more/less than 75%? → more/less than 85%? Etc…). Computerized CASA system to make an objective & consistent measurement.
How should you manipulate the semen sample before you attempt to assess it for motility?Try to work w/ diluted semen (Otherwise too concentrated)
Explain how you assess semen motility w/ a microscopeTake DILUTED semen & place on a pre-warmed microscope slide. Cover w/ standard cover slide. Use a good light microscope or phase-contrast microscope w/ warming table. Examine at 200x to 400x enlargement
**Which way do equine sperm move in, & why?Remember that stallion sperm have an abaxial implantation of the flagella, so move in big arcs, not straight lines!
Which stain do you use to tell if a sperm is dead or not, & what colors tell you if alive vs dead?Eosin-nigrosin stain. Allow live spermatozoa to pump stain out of cell ie. Will be white; dead sperm pink
When making the slide for the eosin-nigrosin stain, what do you NOT want to do?
What does the normal equine sperm look like?Pear-shaped head, Acrosome on cranial half of head, Ab-axial attachment of the midpiece to the head, Smooth, regular midpiece only slightly thicker than the tail, Long & straight tail.
What do abnormal heads, abnormal acrosomes, abnormal midpiece, protoplasmic droplets, & tail abnormalities look like?
To classify abnormal spermatozoa, you must eval at least _________ (number) of them, & what are 6 classifications you can give?At least 100 sperm. Classify w/: Detached head, Abnormal head, Knobbed acrosome, Proximal & distal protoplasmic droplet, Bent & irregular midpiece, Bent & coiled tails
Normal color of sperm?White-grey
Normal volume of sperm per ejaculate?20-100 ml volume of ejaculate
Normal number of spermatozoa per ml? Per ejaculate?50-300 x 10^6 (million). 4-12 x 10^9 (billion) spermatozoa per ejaculate
**How many sperm are morphologically normal in a normal sample?>75% morphologically normal spermatozoa
**How many sperm are progressively motile in a normal sample?>50% progressively motile spermatozoa

Processing semen for insemination

Question Answer
If you are using undiluted sperm, how long do you have?Limited lifespan & fragile, use w/in 30 min
It is better to dilute semen w/ ___Better to dilute semen 1:1 w/ simple inexpensive semen diluter (skim milk based)
**Keep sperm at what temp?Keep at body temp (37°C)
Why does chilling semen extend the life?Decrease temp to decrease metabolism (but Beware of cold shock)
Role of the semen extender → what parts: Protect against temp changes? Energy source? Why do you need Buffers? How do you help w/ Osmolarity? Why use ABx?Protect against temp changes: egg yolk &/or non-fat milk. Energy source: sugars. Buffers: High metabolism, waste products keep pH constant. Osmolarity: correct salt balance. ABx: Suppress bacterial growth
What are 3 commonly used semen extenders?(1) Skim milk (w/ ABx added)
(2) Kenney extender (non-fat milk based extender)
(3) Milk fraction based extenders (casein based) “INRA 96 extender” from IMV Technologies or BotuSemen (Brazilian Manufacturer)
If there will be Less than 2 hours btwn collection & insemination, how much do you dilute your semen w/ semen extender?Dilute semen 1:1 or 1:2 (semen/extender).
If there will be Storage for more than 2 hrs (chilled transport) how much do you dilute your semen w/ semen extender?Dilute semen 1:4 to fully protect against cooling effects.
In some cases, if diluting w/ semen extender isn't going to be sufficient, what can you do?Complete removal of (almost) all-seminal plasma is recommended: centrifugation & reconstitution in semen extender

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