Additional Study Material for Apr 17 Exam Flashcards
What needs to be considering when handling AI semen?
Avoiding temperature shock and contamination
Which species utilizes artificial insemination the most?
Turkey broilers
How is estrus synchronization typically achieved?
Injections of prostaglandin (commercially known as lutalyse) are used to destroy the CL and restart an animal’s estrous cycle
What is the role of FSH in mammalian females?
Stimulate development of graafian follicles and estrogen production
What is the different between sterile and sub-fertile?
Sterile animals cannot reproduce at all, while sub fertile animals reproduce at a less than optimal rate
What is a cryptorchid?
A male in which one or both of the testicles did not descend into the scrotum
What is atresia?
The shrinking of a female’s ovarian follicles over time
How is estrus detected in swine?
Rigid stance, red and swollen vulva
What occurs in the puberal stage?
Endocrine changes lead to the acquisition of reproductive competence (influenced by age and weight)
What are some issues that can affect sperm quality?
Loose heads, misshapen heads, and droplet tails
What is the egg hierarchy observed in female birds?
The largest yolk will be the next to ovulate
What factors influence conception rate?
Semen quality, receptivity of female, ability of inseminator, nutrition, disease, and stress statuses
What does neurohormonal mean?
The release of hormones is controlled by nerves
What is estrus synchronization?
Controlling the estrous cycle so that a herd or flock of females comes into estrus at approximately the same time
What are the advantages of IVF?
- Oocytes are easily obtained from high value animals, both living and recently deceased
- Embryos can be collected at almost any time
What is the function of luteinizing hormone in mammalian males and male birds?
Stimulate testosterone production
What timeframe for insemination has the highest conception rate?
Mid-estrus to end of estrus
How is estrus detected in horses?
Elevation of tail, “winking,”frequent urination
What is a freemartin?
A sterile, female twin to a male
What is the function of follicle stimulating hormone in mammalian males and male birds?
Stimulate spermatogenesis
Why is artificial insemination limited in horses?
To keep stud fees in place
What are the incubation period requirements for birds?
20-28 days (dependent on species) 100 degrees Fahrenheit, high humidity
How is estrus detected in cattle?
Daily checks for signs of heat, “gomer bulls” or other markers
How are the embryos prepared for embryo transfer?
The donor female is super ovulated and bred with two doses of semen, before having the eggs recovered with a uterus flush
What is in vitro fertilization?
A biotech procedure where immature oocytes can be harvested, matured, and then mated with sperm outside of the body
What is a persistent corpus luteum?
A corpus luteum that does not regress and keeps an animal from going into heat
Why are positive energy levels necessary for reproduction?
Low energy can lead to females not entering estrus
What occurs in the adult stage?
Animals have the capacity to produce and release gametes for extended periods
What is embryo transfer?
A process in which eggs are removed from the mother’s reproductive tract and transferred to another female’s tract for development
What is progesterone?
A hormone produced by the corpus luteum that maintains pregnancy
How can reproductive efficiency be measured?
Conception rate or number of live births
How is semen typically stored?
In liquid nitrogen at a temperature around -312 degrees
What controls reproduction hormones in male birds?
GnRH and the photoperiod
Why is vitamin A a critical nutrient of reproduction?
It helps maintain epithelial linings
What are two advantages of embryo transfer?
Embryos can be “sexed,” embryos can be split to form identical twins
What occurs during proestrus in mammals?
Ovarian follicles develop and estrogen levels increase
What factors influence fertility?
- Failure to mate with a fertile male
- Fertilization failure (death of sperm)
- Early embryonic death (doesn’t implant)
- Fetal Death
- Nutrition or disease issues
What occurs during metestrus in mammals?
Corpus luteum begins to form and produce progesterone
What occurs in the senescent stage?
Reproductive capacity decreases due to things such as reproductive tract deterioration and poor nutrition
What occurs in the pre-puberal stage?
Primary follicles are formed, basis for adult behavior can begin developing
Which animal can be artificially inseminated directly in the oviduct, and why?
Birds, because only the left ovary functions
What dilutents are used with sperm?
- Egg Yolk/Citrate Buffer
- Egg Yolk/Tris Buffer
- Milk/Glycerol
- Other Nutrient Source (i.e. protein)/Buffer
What factors are evaluated to determine the timing of AI?
The duration of estrus and the time of ovulation for the female
What are the advantages of estrus synchronization?
Reduced labor for heat detection, helpful in embryo transfer programs
What happens in mammals when conception does not occur?
Prostoglandin from the uterus causes regression of the corpus luteum and the estrous cycle restarts
What differs between extra-embryonic membranes in mammals and birds?
The yolk sac does not degenerate in birds: the allantois and the chorion do not fuse in birds
What are the methods of collecting semen for AI?
- Artificial vagina
- Female or Object Mounts
- Hand Pressure/Massage Techniques
- Electroejaculation
What occurs during diestrus in mammals?
The corpus luteum is fully functioning and produces lots of progesterone
How can semen be sexed?
X chromosome sperm weigh more than Y chromosome sperm and can be separated using dye technology
What can cause a thin-shelled egg?
Dietary deficiencies
What are the causes of sterility and sub-fertility?
Cryptorchid, freemartin, cystic ovary, persistent corpus luteum
Why is calcium a critical nutrient of reproduction in birds?
It is needed for shell formation
What are the four stages of the reproductive life cycle?
- Before puberty
- Puberal
- Adult
- Senescent
What temperature is semen stored at for immediate AI?
40 degrees Fahrenheit
What is the negative feedback that occurs with GnRH and progesterone in mammals?
When an animal is pregnant, progesterone signals to the hypothalamus to stop GnRH release and thus stop FSH and LH release
What are seasonal breeders?
Animals that will only mate during certain times of the year
Why is AI used?
Breed more females, more genetic progress, more economical, safety, disease control
How is hatching initiated?
By a lack of nutrients
What are continuous breeders?
Animals that have no distinct mating season
What can cause a soft-shelled egg?
The egg is laid prematurely before the shell is fully formed
Why is protein a critical nutrient in reproduction?
It forms the sperm, the egg, and the epithelial lining of the reproductive tracts
Why is vitamin E a critical nutrient of reproduction?
It helps maintain fertility
Why is AI semen diluted?
Increase the volume of semen and prolong the life of the sperm
What is vasotocin?
A hormone that behaves similarly to mammalian oxytocin during the egg laying process
What are straws?
Storage vessels that contain between 0.3 and 0.5 mL of semen
What is a cystic ovary?
A follicle that does not rupture and leads to an animal always being in estrus (heat)
How do neurohormonal hormones work in birds?
A nerve connecting the magnum to the hypothalamus is triggered when there is no egg in the magnum
What are additional functions of estrogen in mammals?
- Development of the female reproductive system
- Causes tissue lining the uterus to thicken and increase in blood supply
- Production of thin mucus in cervix
- Makes uterus sensitive to oxytocin
- Makes uterus more resistant to infection
What extra-embryonic membranes are secreted in birds?
Yolk sac, allantois, amnion, and chorion
What is estrogen?
A hormone produced by the graafian follicle that causes sexual excitability
How is estrus detected in sheep?
Sterilized males with markers
What are the phases of the estrous cycle for mammals?
Proestrus, estrus, metestrus, diestrus
What are additional functions of progesterone in mammals?
- Increases growth and blood supply to lining of uterus
- Secretion of uterine milk
- Prevent muscle contraction of uterus
- Production of thick mucus in cervix
What is evaluated about semen in the lab?
Volume, sperm concentration, and sperm quality
Where does prenatal development occur in birds?
In the oviduct
What happens in mammals after conception occurs?
The corpus luteum is maintained and further estrus is inhibited
What can cause a double yolk abnormality?
Two yolks are released at the same time; one yolk is “lost” and found the next day
How long can the egg sustain life after hatching?
3 days
What occurs during estrus in mammals?
Females become receptive to male, estrogen levels are high, surge of LH
What is embryo transfer used for?
To increase the number of offspring from an outstanding female
What is the role of LH in females?
Trigger ovulation and stimulate growth and development of corpus luteum
What is gonadotropin releasing hormone?
A hormone produced by the hypothalamus that tells the anterior pituitary to release FSH and LH
