Artificial insemination Flashcards
2 main reasons for AI
- genetic improvement (more breeding, no geographic issues, sex preselection)
- prevent disease transmission (no direct contact, process semen)
main goal of AI
pregnancy - sufficient fertile sperm at the site of fertilization when the egg arrives
what do you need to be successful at to achieve pregnancy (3)
- semen collection
- semen extension/preservation
- insemination (semen handling, placement, timing)
3 procedures for semen collection
- electroejaculation
- manual stimulation
- artificial vagina
what is electroejaculation
pre-rectum stimulation of pelvic nerves with electrical pulses to stimulate involuntary emission and ejaculation
why is electroejaculation not the preferred method
- welfare concerns
- inferior sample quality
how to do a good job with electroejaculation
- localize stimulus to the desired area (ventral electrodes, finger electrodes)
- use minimum voltage necessary (stepwise increases, rhythmic application)
when is electroejaculation used
- wildlife/zoo collections (when anesthetized)
- one time procedure for breeding soundness exam in intractible/non artificial vagina trained animals (bulls/rams while conscious, deer/cats while anesthetized)
when is manual semen collection done
- tame enough
- ejaculation primarily in response to glans pressure
- boar, dog, rooster
manual collection of boar
- “gloved hand technique”
- boar trained to mount dummy sow –> gloved hand encircles penis, applies pressure to glans penis
- semen collected in wide jar with cheesecloth to separate off gel fraction
- takes 3-20 minutes
manual collection of dog
- mounted on a bitch or more often on the ground +/- bitch present
- penis massaged through prepuce –> prepuce slid behind bulbus glandis, penis encircled with thumb/forefinger –> dog steps over arm so penis is caudal
- semen collected into jar (sperm-rich fraction is second, just collect enough 3rd fraction to get volume)
manual collection of birds
- restrained while the area around the vent is massaged while stroking the back –> erection of phallus (protrudes above floor of cloaca) –> massaged until ejaculation
- semen collected in small cup or aspirated in tube
what is an artificial vagina
- basic design for all
- water jacket provides stimulatory temp (above female temp), pressure
- collection device attached to one end
bull and artificial vagina
- trained to mount a dummy or steer
- pre-collection stimulation sequence (sexual preparation) to maximize sperm collected each time –> “sexual preparation”
what is sexual preparation of bull
- for increasing semen collected
- watch other bulls collect –> false mount –> restraint near stimulus animal –> 2-3 false mounts –> ejaculation
sheep and artificial vagina
- similar to bulls without prestimulation
- generally mount a restrained ewe
stallions and artificial vagina
- mounted on either an estrous mare or trained to a phantom (dummy) mount
- false mounts/teasing give increased semen volume but NOT increased sperm number (increases accessory fluid -> useless)
cats and artificial vagina
can be trained to use it
what is semen analyzed for
- motility
- concentration (sperm/mL)
- volume
- morphology
3 ways semen can be used
- liquid fresh (raw state)
- liquid state following extension and cooling off to room or refrigerator temperature
- frozen (cryopreserved) in liquid nitrogen
uses for raw semen
- fairly common in canine AI
- occasionally in horse farms
advantages/disadvantages of raw semen
- pro: can’t hurt it with incompatible extender
- con: don’t have advantages of extended semen
purpose of using semen extender (6)
- more volume = more stable in temp changes
- nutrient source
- stabilize/protect sperm plasma membrane (cooling)
- antibiotics prevent diseases/bacteria
- buffers prevent pH changes
- maintain osmolarity
purpose of cooling semen
- cooler temp = longer some fertility is maintained
- only slow down deterioration though
disadvantage of frozen semen
lower fertility due to cold damage done on the sperm that decreases the number of viable sperm and fertile life of those that are viable
procedure for freezing semen
- semen mixed with extender in absence of cryoprotectant
- mixture slowly cooled to 4C
- add cryoprotecant
- semen packaged into individual doses
- semen cooled rapidly and stored in liquid nitrogen
insemination of the cow
- rectovaginal method
- hand in rectum grasps cervix while other hand passes insemination gun through vagina
- manipulation allows passage of tip of gun to body of uterus where sperm expelled
insemination of the mare
- vaginal technique
- hand in vagina guides insemination rod to cervix
- finger placed in cervix, pipette directed along it into uterus where semen is expelled
- can also do deep horn insemination
insemination of small ruminants (3)
1) speculum inserted into vagina, deposit semen at external cervical os
2) restrain ewe in cradle, insert speculum into vagina, pipette placed through cervix (frozen semen ok)
3) laparascopic insemination directly into uterus (frozen semen)
insemination of the sow
- vagina is anticlockwise
- matching soft catheter advanced, screwed into cervix
- large volume
insemination of the bitch
- fresh semen: blindly pass catheter into cranial vagina to deposit sperm or use speculum
- frozen semen: laparoscopic insemination or transvaginal endoscopic techniques
insemination of the queen
- intravaginal: under sedation in dorsal recumbency with elevated hind end
- intrauterine: surgically, laparoscipally, transcervically (via vagina)
insemination of birds
- massage same way as male
- vent everts –> caudal part of reproductive tract
- semen placed into opening
