1. ART1: insemination Flashcards
what is artificial insemination
the deliberate introduction of a sperm/semen sample into the cervix or uterine cavity by catheter
what are the reasons for using artificial insemination
- to allow greater access to superior genetics/maximise genetic improvement
- to reduce mating costs
- to reduce mating risls
- to control reproductive diseases
- to allow use of dead or injured sires
- as part of embyro transfer regimes
- to increase production/breeding efficiency
how is ejaculate collected
teasing followed by collection using
- artificial vaginal with teaser or dummy female
- teaser or dummy female and manual manipulation of the penis
- electro ejaculation
under what circumstances may we need to examine semen
- as part of breeding soundness exam
- when lower fertility is suspected
- when abnormal sexual behaviour is seens
- before sale or the breeding season
- if a pathogen infection is suspected
what is the ideal temperature to assess sperm motility
37 degrees
what is assessed from a semen sample
- ejaculate volume
- ejaculate colour/smell
- sperm concentration
- sperm morphology
- sperm live:dead ratio
- sperm swimming speed
- sperm DNA fragmentation
how do you count sperm using a hemocytometer
- find the middle square and each corner square
- count the sperm in all 5 squares
- when sperm are on the lines, only count ones in top and left sides
- multiply total by 5
- multiply that number by 10000 (to account for surface area)
- multiply that total for dilution factor if there is one
- this number = sperm concentration
- sperm concentration x volume = total sperm output
sperm that stain pink after being stained with nigrosine eosin stain are
dead = their membranes have degraded and pink binds to nuclear material in head
list and describe sperm abnormalities
are there differences in sperm morphology between species
yes - esp in rats (hooked head)
list sperm preservation options and their respecitve life spans
- fresh-exteded (room temp). 8 hours
- extended and cooled @5C = 4-10 days
- extended and frozen @ -196C then thawed = indefinite BUT motility drops post thaw
sperm lifespan extender solutions aim to:
- protect sperm during cooling/freezing/warming
- supply an energy source to sperm
- maintain pH, osmolarity and ionic strength
- prevent bacterial growth
what kind of protective agents are used in semen preservation
milk or egg protein/glycerol
outline the process of cryopreserving semen
stage 1:
- cryoproteins added glycerol/DMSO or proteins and large molecular weigh sugars)
stage 2:
- controlled freezing rate (slowly to 5C, equilibriation 2-4 hrs then loaded into straws and transfered into liquid nitrogen
stage 3:
- controlled thawing rate
- generally at 37C
what happens if cryopreservation occurs too slowly
- cells dehydrate and solute concentration increases
- solutes tend to precipitate
- cells shrink beyond a minimum compatability
- cell is damaged and will be non functional at thaw