Lecture 12, 13 - Breeding Methods I and II Flashcards
One of the biggest advantages to natural service:
Delivery of an entire ejaculate to the appropriate anatomic site in the female reproductive tract
What is a “dose” of semen?
The number of PMS or of total sperm that the industry has determined to be adequate to produce acceptable pregnancy rates in that species.
What is a straw?
A straw is a package of frozen semen
T/F: A dose is equivalent to a straw
False, a dose is not always equivalent to a straw. It dose can be one straw, or several.
In the bitch, what is the PMS and site of deposition for fresh extended semen:
FE: ≥ 100 million; vagina
In the bitch, what is the PMS and site of deposition for cooled, trasnported semen?
CT: ≥ 100 million; vagina and uterus
In the bitch, what is the PMS and site of deposition for frozen/thawed semen:
FT ≥ 100 million; uterus
In the mare, what is the PMS and site of deposition for fresh extended semen:
FE: ≥ 500 million; uterus (body)
In the mare, what is the PMS and site of deposition for cooled, transported semen:
CT: ≥ 500 million; uterus (body)
In the mare, what is the PMS and site of deposition for frozen/thawed semen:
FT ≥ 250 million; uterus (horn)
In the cow, what is the PMS and site of deposition for frozen/thawed semen?
FT: ≥ 10 million; uterus (body)
Artificial media designed to enhance sperm survivial when insemination cannot be performed immediately.
Semen Extender
To use semen at a later time and ensure sperm survival, the activity and metabolic rate of sperm must be decreased. This is done via:
Cooling and Freezing
What kind of damage is done to sperm with freezing and thawing?
- Phase transition of sperm plasma membrane
- Direct damage to organelles by ice crystal formation
- Rapid ice crystal formation in extender –> hypertonicity of media –> dehydration of sperm
What are the semen extender components that enahnce survival of frozen/thawed semen?
- Cholesterol (egg yolk)
- Cryoprotectants (glycerol)
- Metabolic substrates (disaccharides)
- Buffers
- Antimicrobials
Rapid freezing of semen over/in liquid ____ vapor produces the best results.
Nitrogen
How well the sperm of a given species cryopreserves is largely dictated by the percentage _____ composition in the plasma membrane.
Cholesterol; the more cholesterol in the plasma membrane, the better the sperm freeze and thaw
Which two domestic species have the larvest percentage of cholesterol composition in the plasma membrane of sperm, allowing them to cryopreserve well?
Bulls and dogs
Rapid freezing dictates rapid _____.
Thawing
Water contamination causes ________ to sperm.
Irreversible damage
At best, usually only __% of initially PMS survive the freeze-thaw process.
50%
As long as sufficient sperm numbers available to attain minimum insemination dose, PMS of ___% or better is acceptable.
30%
Always add extender to semen and pour slowly, like a beer, why?
To avoid creating/adding extra oxygen to the semen sample
Dilution of cooled, trasnported semen to concentrations that optimize sperm survival depend on?
Species
Cooled transported semen is shipped at what temperature in the stallion and dog?
5˚C
Cooled trasnported semen is shipped at what temperature in the boar?
15-18 ˚C
Fresh extended semen may be diluted as little as:
1 part semen: 1 part extender by volume
Fresh extended semen can be maintained at room tempurater out of sunlight for up to ___ hours prior to use.
3
Pregnancy rates are optimized when sperm are available in the ____ of the uterine tubes awaiting arrival of oocytes after ovulation.
Ampullae
In most cases, we breed the female prior to ovulation, except in which species:
- The bitch
- The mare with frozen-thawed semen
Ejaculated sperm from fertile male dog can survive up to __ days in the uterine tubes.
Seven
T/F: A single breeding during estrus often is adequate to achieve pregnancy.
True - timing is more forgiving than when we do AI in dogs, because a fertile stud dog’s sperm will live in her tract for up to 7 days.
In natural mating, how many sessions/day should you allow for mating if the dogs are in the same location?
Two 45 minute sessions/day
Once the stud dog has stepped over with one hind leg to form a copulatory lock with the bitch, which fraction of semen does he ejaculate?
Fraction #3
A copulatory lock should be at least 5 minutes or longer. Anything less than five mintues is considered _______, and is less likely to result in pregnancy.
slip mating
The expected pregnancy rate of natural mating in the bitch:
≥ 75%
Why is fraction #3 of the ejaculate important in the male?
It pushes the sperm rich fraction “up hill” through her cervix.
Most common cause for use of fresh extended semen in the bitch?
Impotentia coeundi (inexperienced male, psychogenic impotence, bitch with poor perineal conformation, physical impediments)
One advantage of using fresh extended semen is that is allows for a ____ on the male prior to breeding.
BSE
When using fresh extended semen in the bitch, we can assume that the sperm will survive in the ampulla for at least….
2 days
When using fresh extended semen in the bitch, we usually breed her twice between days 4-8 of estrus. But if we are breeding only once, which days do we breed on?
Day 4, 5 or 6 of estrus
Fresh extended semen in the bitch should be diluted to at least what by volume?
1:2
How do we simulate a copulatory lock when administering fresh extended semen to the bitch?
Secure thumb or finger into the vestibule
After injecting fresh extended semen in the bitch, it is important to remain “tied” and stimulate the vestibular floor of the bitch for at least 10 minutes. Why is it important to stimulate the vestibular floor?
It simualtes the bulbus glandis of the stud dog penis inside the vagina, which helps the bitch to contract her muscles, and pull the semen up.
Insemination volume is dependent upon the size of the bitch. Large and giant breed bitches howeve,r require insemination of sperm-rich fractin followed by slow instillation of extender to force sperm-rich semen into the uterus using ______.
MAVICatheter
When receiving cooled trasnported semen, it is important to evaluate what?
Progressive motility, total sperm count, and calculate the number of PMS
If I receive a shipment of cooled trasnported semen, can I add an extender to it?
NO! The volume that you receive is the volume you are stuck with, never mix extenders!
Pregnancy rates in the bitch of cooled trasnported semen
60-80%
Cooled trasnported sperm live for at least ____
2 days
Frozen-thawed sperm live less than ___
24 hours
What is the dose of frozen-thawed semen in the bitch?
≥ 100 million PMS in < or = to 2mL is preferred
Maximum time from when you thaw the semen to the time you put it in the bitches uterus needs to be?
5 minutes or less!!
What is the most popular method for breeding with frozen-thawed semen in the bitch?
Surgical insemination into the uterine horn and force the semen up into the uterine tube on ~ day 5 of estrus
Expected pregnancy rate in the bitch with frozen-thawed semen administered surgically?
50-85%
Besides surigcal insemination, what other way can you administer frozen-thawed semen to the bitch?
Transcervical endoscopic insemination
Can you perform AI on alpacas?
No, they are bred exclusively by natural service due to technical difficulties with semen colleciton, evaluation, dilution and cryopreservation.
The macho (male alpaca) ejaculates directly into the henrba’s _____, and alternates between horns about 22 times.
uterus
After natural mating of the hembra, we test behavior 2 days later to check for?
Pregnancy - if she kushes, then she did not get pregnant and can be bred again
Prolonged cohabitation of macho and hembra decreases….
sexual activity (the macho will tend to lose interest)
What kind of semen is the most commonly used in the USA for AI in the dairy cow?
Frozen-thawed
What is the dose for frozen-thawed semen in dairy cows?
One 0.5 mL straw with 10 million PMS
How do we administer the semen when performing AI in the dairy cow?
Transcervical procedure for intra-uterine semen deposition.
Insert non-dominant arm into rectum - grasp cervix - stretch it forward to straighten fornix - insert AI gun along dorsal vaginal wall and advance to external cervical os - trasnrectally manipulate gun through cervical rings - palpate tip of AI gun in uterine body - expel semen - withrdraw AI gun - stimualte clitoris
T/F: Sex-selected semen is 100% accurate.
False, but over 90%
T/F: Pregnancy rates are slightly lower with sex-selected semen than with non-sex selected semen.
True (manipulation might have deleterious effects to plasma membrane of sperm)
Expected pregnancy rates (single cycle) with AI in heifers vs lactating cows
Heifers: 60-65%
Lactating cows: 20%
What is the predominant breeding method of the ewe in the US?
Natural breeding
What is the dose of frozen-thawed semen in the ewe?
20 million PMS - dose divided between uterine horns
Fresh extended semen is most often used by dairy and purebred goat breeders. AI is performed over 12 hours after onset of estrus, and we look at the mucus for what?
AI at hte time mucus turns from clear to cloudy
Why do we need to perform AI laparoscopically in the sheep, but can do a vaginal approach in the doe?
Becuase sheep has rings along cervix that are not lined up, making it difficult to get through her cervix. The doe has a straight shot through her cervix, so it is easy to pass the AI pipett through the cervical rings and deposit the semen in the uterine body.
Is frozen-thawed semen common in the doe? Why or why not?
No - most buck semen does not generally survive cryopreservation well and long-term storaage has deleterious effects upon sperm.
What is the most common breeding method in the sow?
AI - fresh extended semen from boars on site or cooled trasnported semen from boars at stud
Does frozen semen work in pigs?
No, their semen does not preserve well in low temperatures. Their cooled semen is even cooled to a lesser degree than other species.
Commercial sows may be bred with semen from multiple sires during a single cycle using “pooled” semen. Does this increase fertility?
Yes
Why does fresh extended semen from pigs need to be filtered?
They have large volume ejaculates with copious gel fraction that needs to be filtered out PRIOR to extension.
Administer fresh extended semen in the sow ___ hours after onset of estrus, and again ___ hours later.
24 hours; 12 hours
Administer fresh extended semen in gilts ___ and ___ hours after onset of estrus.
12 and 24
What is the technique used to administer fresh-extended semen in the pig?
“Spirette” - rotate pipette counter clockwise to lock it into the cervix, then hang a vessel containing hte semen at the other end, and hold it up to allow insemination to proceed via gravity flow
Fresh extended semen - expected per cycle pregnancy rate in the sow:
> 90%
Cooled shipped semen in the boar is shipped at ____˚C
, and can be maintained in an incubator at that temperature for up to ___ days.
15-18 ˚C; 4 days
How do we know a mare is in heat using U/S?
When her follicle is over 35 mm in diameter and some edema is present
Do we induce ovulation before or after breeding the mare?
For most circumstances, we breed her before ovulation.
But when using frozen-thawed semen, we will induce ovulation first, and then breed her after ovulation.
There needs to be a minimum of ___ individuals to perform natural service of the mare safely.
2
What is the purpose of the breeding roll in the stallion?
To keep him from achieving intromission too vigorously
Why do we use leg restraints and put boots on mares when naturally breeding her?
To avoid kicking the stallion, and so that her back feet do not cut the stallions scrotum.
Why do we wrap the mares tail before breeding?
The mares tail hair can actually cut the penis if it gets caught in it.
Teaser stallions are used to test mount the mare for the safety of the ______ stallion.
Breeding
What do we wash the stallions penis off with before and after natural service?
Water - no harsh detergents or soaps b/c they will disrupt the natural flora
After breeding, peopel will often perform “impregnation” aka “reinforcement breeding”. What is this?
Dilution of dismount sample with semen extender and infusino of semen into the uterus. In reality this is just like AI - but we do not call it AI, becuase it would be illegal in certain circumstances. The presence of antibiotics in the semen extender is what most likely increases the mares chances of getting pregnant.
Why do we replace Caslick’s sutures in the mare post-breeding?
To keep her from aspirating air.
Frequency of breeding in thoroghbred industry
Goal is to breed only ONCE per estrus; doubling is strongly discouraged
Frequency of breeding in privately owned stallions with mares boarding:
May breed every other day until mare is out of estrus
Can a vet vaccinate against equine arteritis virus in Missouri?
Needs permission from the state vet first!
Pregnancy rates of the mare with natural service: single cycle, seasonal, live foal rate
- Single cycle: 65%
- Seasonal: 90%
- Live foal rate: 80%
Foal heat breeding results in _____ lower rates.
15-20%
Reinforcement breeding increases pregnancy rates by ___% if > 200 million sperm inseminated.
12
It is important to maintain fresh-extended semen from a stallion in a dark area at room temprerature, and inesminate the mare within __ hours.
3
Describe the procedure for AI using fresh extended semen:
- Pass pipette to cranial vagina
- Canulate external cervical os with index finger
- Advance pipette along finger, through the cervix, approximately 1-3 cm cranial to finger tip
- Deposite semen into the uterus, monitoring for back flow.
Pregnancy rates using fresh extended semen in the mare:
Single cycle: 70-75%
Seasonal: > 80%
To prepare cooled trasnported semen form the stallion, dilute using skim milk-based extender to ____ million/mL. Add at least __ parts extender to __ part semen by volume.
25-50 million/mL; 2 parts extender:1 part semen
What is the industry standard for shipment of cooled, transported semen?
2 doses; each containing 1 billion PMS at the time of packaging (assume that at least 50% will die in transit, and we need to have at least 500 million PMS at the time of delivery)
It is important to always evaluate the cooled trasnported semen prior to breeding of the mare. What things do we look at?
- Progressive motility
- Concentration x volume/dose = sperm count/dose
- Calculate the number of progressively motile sperm/dose
- Compare to industry standard minimum
Do we warm the cooled trasnported semen prior to insemination in the mare?
No!! Inseminate mare with semen DIRECTLY out of shipper.
We can inseminate both doses of cooled, transported semen in the mare on date of arrival if….
PMS in one dose is <500 million and if combined volume not excessive
Is it recommended to breed the mare on successive days?
Not recommended, the best incubator for semen is hte mare!
T/F: Use of a second dose for breeding of a second mare is okay.
False - you need permission from the stallion owner first
Can we induce ovulation before breeding when using cooled, transported semen?
Yes, it takes 48 hours after inudction to ovulate in the mare
Pregnancy rates in the mare with cool-transported semen:
- Single cycle: 39-65% (better if PM > 60%)
- Seasonal: 68-91%
T/F: AI with frozen thawed semen in the mare has lower pregnancy rates than by other methods, even if the same number of PMS are inseminated.
True
How you thaw semen is dependent on how it was ____. Therefore, thawing instructions must be strictly followed.
Frozen
There is no industry standard for the dose of frozen-thawed semen, however our goal is to have at least 250 PMS post-thaw. Why is this number lower than what we require for cooled semen?
Because we tend to deposit the frozen-thawed sperm via deep horn insemination at utero-tubular junction using a special pipette. With cooled shipped semen, we deposit it into the body of the uterus, not in the horn.
Best vs worst mare candidates for frozen-thawed semen
best candidates: young maidens < 6 years, and foaling mares
worst candidates: old maidens, barren mares, mares with history of reproductive dysfunction
How long do frozen-thawed sperm from a stallion live?
6-12 hours
How long does the oocyte live for in the mare?
8-12 hours
Highest pregnancy rates in the mare with AI using frozen-thawed semen is to inseminate ___ hours before to ___ hours after ovulation.
12 hours; 6 hours
Timing of insemination in the mare with frozen-thawed semen (two ways)
- Induce ovulation when 35 mm follicle present, AI 24 and 40 hours later
- Induce and confirm ovulation, AI immediately after ovulation (very labor intensive)
Expect pregnancy rates using frozen thawed semen to be about ___ of what it would be using cool shipped semen from the same stallion.
1/2
