(02) - AI Flashcards
just read the first page
(D. Semen Collection)
1-3. What are the three methods?
- electroejaculation
- manual stimulation
- artificial vagina
(Electroejaculation
- Per-rectum stimulation of pelvic nerves with electrical pulses to stimulate involuntary emission and ejaculation.
- Not the preferred method… why?
- To do the best possible job do what two things?
- used in what?
- welfare concerns and inferior sample quality
- localize stimulus to desired area (ventral electrodes, finger electrodes)
use minimum voltage necessary (stepwise increase, rhythmic application)
- wildlife/zoo collections (when immoblized/anesthezised)
one time procedue for BSE in intractable/non-vaginal trained animals (concious bulls and rams - un cats and deer)
(D.ii. Manual)
- Done in species that are what two things?
- usual method in what animals?
- Also possible by rubbing type massage of what in the bull?
- tame enough and have ejaculation primarily in resopnse to glans pressure
- boar, dog, and rooster
- the accessory glands and pelvic urethra per rectum (this often done prior to electroejaculation)
(D.ii. Manual)
(Boar - “gloved hand technique”)
- Boar trained to mount a dummy sow.
- When he starts thrusting 2-4 fingers of a gloved hand encircle the penis and apply pressure to the glans penis, mimicking that applied by the what?
- Semen is collected in a wide-mouthed jar covered with cheesecloth to separate off the gel fraction. Ejaculation takes 3-20 minutes.
- cervix
(D.ii. Manual)
(Dog)
- Similar to the boar, can be done mounted on a bitch or more usually on the ground +/- bitch present
- Penis is massaged through prepuce till dog starts doing what?
- At this point the prepuce is slid back behind the bulbus glandis and the penis encircled with thumb and forefinger behind these. At some stage the dog will want to step over your arm so his penis is directed caudally, between the hindlegs.
- Semen is collected into a glass or plastic jar (a latex bovine cone with a serum tube attached works well – in this case the cone goes over the penis and the open end is held behind the bulbus glandis with the encircling thumb and finger.
- The sperm rich fraction comes out when?
- thrusting
- second
(so you basically just collect enough 3rd fraction (clear prostatic fluid) to give you the volume you want.)
(D. ii. Manual)
(Birds)
- Bird is restrained while the area around the what is massaged while simultaneously stroking the back.
- Arousal results in what?
- vent
- erection of the phallus (intromittent or not) which protrudes above the floor of the cloaca.
This can now be massaged until ejaculation. The semen is collected in a small cup or aspirated in a tube.
(D.iii. Artificial Vagina)
- Basic design is the same for all. A water jacket is used to provide the necessary stimulatory temperature, usually above normal body temperature of the female (42-48 degrees centigrade for most vs ~ 38 degrees for body temperature). Pressure is also provided by the water jacket or supplemented by inflation with air. A collection device is attached to one end to receive the semen.
- Bull is trained to mount a dummy or sometimes a steer (for disease transmission reasons females are not allowed on many bull studs). In order to maximize the number of sperm collected on each occasion the bull undergoes a pre-collection stimulation sequence termed sexual preparation.
This generally involves what?
- having him watch other bulls collect,
hen a false mount followed by restraining him near the stimulus animal (no mount allowed) then another 2-3 false mounts before allowing intromission (AV) and ejaculation.
(This process significantly increases the # sperm collected from bulls.)
(A similar system is used in sheep (often without prestimulation), only they generally mount a restrained ewe.)
(D.iii. Artificial Vagina)
- Stallions may be mounted on either an estrous mare or trained to a phantom (dummy) mount.
Do False mounts or prolonged teasing of the stallion give increased semen volume?
significantly increase sperm number?
- yes
NO! (just increases the amount of accessory fluid, which we usually don’t want.)
(Cats can also be trained to use an artificial vagina.)
(E. Semen Extension and Preservation)
- semen is evaluated by what criteria?
- semen may be used when?
- motility, conc, volume (may also be examined for morph)
- liquid fresh (raw state)
liquid state following extension and cooling to room or frigde temp
frozen (cryopreserved) in liquid nirtrogen
(E.i. Raw Semen)
- This is used fairly commonly in canine AI, where the semen is collected, evaluated, and placed straight into the waiting bitch.
- It is also occasionally used on horse farms.
- The advantage of this is what?
- disadvantage?
- can’t hurt it with an incompatible extender
- don’t have the advantages of extended semen.
(E.ii. Liquid Extended Semen)
- xtended semen has greater volume so it is what?
- The extender provides what for sperm?
- Extender components help stabilize the sperm plasma membrane and protect it, especially during cooling (milk proteins, egg yolk lipids, chelators).
- Antibiotics in the extender help prevent disease transmission and prevent bacterial overgrowth during storage (penicillin, aminoglycosides, polymixin).
- Buffering capacity of extender components prevents pH changes during storage as a result of what?
- osmolarity is maintained
- more stable with regard to rapid temperature changes
- nutrient source (glucose/fructose)
- sperm metabolism (sodium bicarbonate, phosphates)
(E.ii. Liquid Extended Semen)
- Storage temperatures for fluid semen range from room temperature (18-20 degrees centigrade often used is swine - lasts 5-7 days, also for short term storage < 6 hours in horses) down to refrigerator temperature (4-5 degrees centigrade - the most common storage temperature for same day and overnight shipping of semen for dogs and horses).
- Generally, the cooler the temperature the longer some fertility is maintained. However, the semen is deteriorating from the moment of collection, and even the best extenders only slow down this process.
Efforts should be made to extend semen as soon as possible after collection and then use it before fertility declines.
(E.iii. Frozen Semen)
- With the possible exceptions of cattle and dogs, frozen semen has a lower fertility than natural mating or liquid stored semen. This is due to the increased cold-damage that is done to the sperm, decreasing the number of viable sperm and probably the fertile life of those that are viable.
- Components of the freezing extender are similar to that of extenders for fresh semen except that a what is added?
and the concentration of what is higher?
- 2-step cooling procedures are generally the most likely to succeed.
In this system, following collection the semen is mixed with the extender in the absence of a cryoprotectant*. This mixture is then slowly cooled to around 4 degrees centigrade, at which point the cryoprotectant is added and the semen is packaged into its individual doses for freezing. The semen is then cooled rapidly and stored in liquid nitrogen at –196 degrees centigrade.
*In other cases the cryoprotectant is already present but a slow-cool to 4 degrees prior to freezing is still often performed.
- cryoprotectant (generally glycerol or ethylene glycol)
egg yolk (provide more staibility for sperm PM)
(F. Isemination)
- Method of insemination varies with species and occasionally with type of semen. In all species cleanliness and atraumatic technique is paramount. The other necessities for success are correct handling of the semen and ensuring the female is close to ovulation at the time of insemination.
…just read these and make a guide as you see fit at the time….
