Jax Handbook - Chap 13 Breeding Strategies & Techniques Flashcards Preview

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True or False:  Males reach sexual maturity later than females.      


Males usually reach sexual maturity by 6 weeks, females by 4–6 weeks.


How long is the murine estrous cycle?
a.         4 to 5 days
b.         7 days
c.         8 days
d.         10 days

a.         4 to 5 days


What is the average gestation length for mice?
a.         14-16 days
b.         18-21 days
c.         22-25 days
d.         26-28 days

b.         18-21 days


True or False: Weaning age can vary depending on the strain of the mice.


Most strains are weaned at 21 days, some at 28 days. Do not remove pups from mother before 17 days unless they are transferred to a foster mother.


True or False:  The post partum estrous is the estrous period that females enter within a few hours of giving birth. 



What is the average time for a generation?
            a.         6 weeks
            b.         7 weeks
            c.         8 weeks
            d.         About 10 weeks

d.         About 10 weeks


What is the reproductive lifespan for the female?      

Strain dependent.

For inbred strains, fecundity usually begins to decrease with the 3rd litter. By 6–8 months, some females become infertile, and litter size for most females of most strains has diminished to the point that it is more economical to set up a new breeding pair


What is the reproductive lifespan for the male?

Strain dependent.

Fertility in some strains decreases starting at 10 months


When does implantation occur?

Implantation normally occurs during the fifth day after conception.

However, if a female is nursing, implantation may be delayed for more than a week, during which time embryonic development is held in suspension.


True or False:  Delayed implantation may occur if the female is nursing a litter.



Cage location may decrease breeding performance, and mothers may
            a.         Cannibalize pups
            b.         Resorb litters
            c.         Stop breeding 
            d.         All of the above

            d.         All of the above


What is the most common lighting cycle for breeding? 

The most common cycles are 14:10 (on:off) and 12:12.


True or False: Falling barometric pressure can cause some strains to become hyperactive, reducing breeding performance. 




What is the thermoneutral temperature for mice? 

About 27-28C (80-82F)


What air quality measures may help promote successful breeding?
            a.         Have a “no perfume” policy for those who are working with mice
            b.         Keep mice away from noxious fumes
            c.         Using clean forceps or clean/new gloves between cages
            d.         All of the above

           d.         All of the above


True or False:  Wild-derived mice may be more sensitive to handling stress.



In breeding cages, what handling techniques may be helpful to maintain performance? (more than one answer is correct).
            a. Working as fast as possible
            b. Do not change cages until pups are at least 2 days old
            c. Assign regular caretakers
            d. Minimize handling and checking on the mice. 

   b. Do not change cages until pups are at least 2 days old
            c. Assign regular caretakers
            d. Minimize handling and checking on the mice.


What is an optimal fat content range for breeder diets? 

4-12% w/w


True or False: Breeding pairs can be set up at 6-8 weeks of age. 



.       At what age should breeding pairs be replaced for optimal performance?
            a. As they approach 6-8 months of age
            b. 9-10 months
            c. 12 months
            d. 15 months

         a. As they approach 6-8 months of age


If a female breeder does not produce a litter within 60 days of pairing or within 60 days of her last litter, you should consider…
            a. Replacing her
            b. Checking the age of the male
            c. Waiting another 2 months
            d.  a and b

            d.  a and b


True or False:  A male breeder that is over 1 year of age, and is infertile with a young, fertile female should be replaced. 



Name two viruses that can affect breeding performance. 

Parvovirus: losses at 7-10d of age

MHV: losses at weaning


True or False:  Chronic infectious disease, infestations of parasites and obesity can impair breeding.



Name three female:male breeding ratios that can be used. 

Pair mating

Trio mating: 2 females & 1 male

Harem mating: male is rotated to other cages


What may happen when inbreeding a line of heterogeneous mice?
            a. No change in fertility
b. They may become less fertile within about 3 generations, and eventually become infertile
            c. They will become more fertile after 3 generations

b. They may become less fertile within about 3 generations, and eventually become infertile


What is a copulatory plug? 

A waxy mass of ejaculate that is produced by the male's seminal vesivle and coagulating gland that indicates breeding has taken place recently


How long do copulatory plugs remain visible? 

Generally 10-12 hours post mating, though there is strain variation


What is the Lee-Boot effect? 

The Lee-Boot Effect (Van Der Lee and Boot, 1955) describes the phenomenon of estrus
suppression in a group of densely-housed female mice that is removed from male mouse urine
for 28 days


What is the Whitten Effect?

The Whitten Effect (Whitten, 1956) describes the process of a female in anestrus
being induced into estrus by exposure to male mouse urine.


What tips may help when attempting to foster pups onto a new mother?
            a. It is better to try to foster younger pups.
            b. Try to choose a mother with pups similar to the age you want to foster.
            c. Try to limit the size of the foster litter to less than 6 pups

d.  All of the above

d.  All of the above


When can hysterectomy derivation be used?
a. When bringing a new strain into a facility with a higher level of pathogen protection
  b. When more females are available than males of a given strain
     c. If success rate of IVF is not known in the strain
d. All of the above

d. All of the above


True or False:   Ovarian transplantation is the surgical implantation of fresh or frozen ovarian tissue into the ovarian bursa of  a 4 to 5 week old female of histocompatible strain. 



What technique can be used with “dead” or thawed cryopreserved sperm?

Intracytoplasmic sperm injection (ICSI):
Insertion of frozen or thawed
sperm head into egg cytoplasm in

• Sperm do not need to be live.
• Sperm can be collected from dead male if
sperm is collected and cryopreserved as soon
as possible.


Superovulation by injection of ___________ induces ovulation of a greater number of eggs than normal.

Briefly describe the protocol.


Female mice are injected interperitoneally (IP) with pregnant mares serum (PMS) between 1:00 and 4:00 PM of Day 1. The females are housed 5 or less per cage.

On Day 3, forty-two to fifty hours after the PMS injection, the mice receive an IP injection of human chorionic gonadotropin (HCG). Immediately following injection, a female is mated with the appropriate stud male. Males, 8 weeks of age or older, are housed individually and the female is always placed into his cage.

Ovulation occurs approximately 12 hours after the HCG injection, at which time the eggs can be fertilized.


What is one, often overlooked, cause why a pair of mice are not breeding? 

Two mice of the same sex were paired


True or False:  The most common cause of fetal resorption is stress. 



Bruce Effect

recently conceived females resorb fetuses during early pregnancy in the presence of an unrelated male.

"Bruce is a strange male."


Vandenbergh Effect

acceleration of puberty of juvenile females in response to male urine


Lee-Boot Effect

Suppression of estrus cyclicity among group housed females that are isolated from males

"Booted out of estrus."


Whitten Effect

Synchronization of estrus in response to a male.

"Smitten with Whitten."