ART1: insemination

Question 1

what is artificial insemination

Answer 1

the deliberate introduction of a sperm/semen sample into the cervix or uterine cavity by catheter

Question 2

what are the reasons for using artificial insemination

Answer 2

• 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

Question 3

how is ejaculate collected

Answer 3

teasing followed by collection using
- artificial vaginal with teaser or dummy female
- teaser or dummy female and manual manipulation of the penis
- electro ejaculation

Question 4

under what circumstances may we need to examine semen

Answer 4

• 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

Question 5

what is the ideal temperature to assess sperm motility

Answer 5

37 degrees

Question 5

what is assessed from a semen sample

Answer 5

• ejaculate volume
• ejaculate colour/smell
• sperm concentration
• sperm morphology
• sperm live:dead ratio
• sperm swimming speed
• sperm DNA fragmentation

Question 6

how do you count sperm using a hemocytometer

Answer 6

• 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

Question 7

sperm that stain pink after being stained with nigrosine eosin stain are

Answer 7

dead = their membranes have degraded and pink binds to nuclear material in head

Question 8

list and describe sperm abnormalities

Answer 8

Question 9

are there differences in sperm morphology between species

Answer 9

yes - esp in rats (hooked head)

Question 10

list sperm preservation options and their respecitve life spans

Answer 10

• 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

Question 11

sperm lifespan extender solutions aim to:

Answer 11

• protect sperm during cooling/freezing/warming
• supply an energy source to sperm
• maintain pH, osmolarity and ionic strength
• prevent bacterial growth

Question 12

what kind of protective agents are used in semen preservation

Answer 12

milk or egg protein/glycerol

Question 13

outline the process of cryopreserving semen

Answer 13

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

Question 14

what happens if cryopreservation occurs too quickly

Answer 14

• 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

Question 15

what happens if sperm is cryopreserved too fast

Answer 15

• cells do not dehydrate
• large ice crystals form inside cell
• cell isdamage leading to non functional cell upon thaw

Question 16

what do we want to occur to sperm during cryopreservation

Answer 16

• water leaves cell which progressively dehydrates
• small ice crystals form inside cell
• on thaw ice crystals melt and cell rehydrates

Question 17

how successful is freezing sperm in bulls and how is it collected and used

Answer 17

• Semen usually collected with artificial vagina
• Semen freezes well
• Uterine insemination easy after training
• Success similar to natural mating
• 50% calving rate to single insemination

Question 18

how successful is freezing sperm in ram and how is it collected and used

Answer 18

• Reasonable survival after freezing
• Trans-vaginal uterine insemination difficult so either cervical or laparoscopic uterine insemination used
• Success rates depend upon site of insemination
• 40% lambing rate for cervical insemination of non-frozen semen
• 70% lambing rate for uterine insemination of non-frozen semen
  *

Question 18

how successful is freezing sperm in boars and how is it collected and used

Answer 18

Poor freezing ability so most is extended in 50 ml bottles shipped at ambient temperature not cooled
Uterine insemination easy
Success similar to natural mating (80%)
75% farrowing rate to two inseminations at one oestrus

Question 19

how successful is freezing sperm in stallions and how is it collected and used

Answer 19

Poor freezing outcome and significant individual variation
Fresh
Chilled semen shipped in plastic bags in thermos
Frozen semen stored in 1.0 or 4.0 ml straws
Uterine insemination easy
Success rates
Natural mating (75% conception)
Chilled semen AI (65% conception)
Frozen-thawed semen AI (45% conception)

Question 20

how successful is freezing sperm in dogs and how is it collected and used

Answer 20

Poor freezing outcome and significant individual variation
Uterine insemination difficult but possible
Success rates
Natural mating (90% conception),
Chilled semen AI (65% conception),
Frozen-thawed semen AI (50% conception)

Question 21

how is sperm sexed

Answer 21

• X chromosomes have more DNA (heavier)
• sperm is labelled with a DNA fluorescent dye and sorted with flow cytometry
• droplets containing spermatozoa emitting fluorescent signal acquire electrical charge
• spem sorted into collection tubes by an electromagnetic field