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