Canine: Estrus and Breeding Flashcards
Which of these describes the canine estrrous cycle?
Seasonal
Non-seasonal
Polyestrus
Monoestrus
Induced ovulation
Spontaneous ovulation
Monoestrus
Non-seasonal
Spontaneous ovulation
What surrounds a bitch’s ovaries that must be accounted for when spaying her?
Adipose tissue
Don’t spay the fat
Puberty is defined as the ability of the hypothalamic neurons to produce sufficient ______.
GnRH
Smaller breed dogs go into puberty around
a. 2-6 months of age
b. 6-10 months of age
c. 10-14 months of age
d. 12-24 months of age
b. 6-10 months of age
Do larger breed dogs generally come into puberty earlier or later than small breed dogs?
Later
Great Dane - up to 18 months
Around what age do dogs reach maximum reproductive capability?
3 years
2nd, 3rd, or 4th estrus
Match the following lengths of time to the appropriate phase of the estrous cycle (one value is used more than once):
9 days
2 months
5 months
Anestrus: 5 months
Proestrus: 9 days
Estrus: 9 days
Diestrus: 2 months
In which stage of the cycle are bitches either pregnant or pseudopregant?
Diestrus
What stages of the cycle coincide with the follicular phase? Luteal phase?
Follicular phase: Proestrus + Estrus (18 days)
Luteal phase: Diestrus (2 months)
What is the time period from the beginning of one estrus to the beginning of the next estrus? What is the average duration?
Interestrus period
7 months
What effect does a shortened (<90 days) anestrus period have?
Decreased fertility
Which 2 breeds may have a shorter interestous period?
Rottweilers
German Shepherds
How many cells thick is the vaginal stratified squamous epithelium in anestrus? End of proestrus?
2-4 cells
20-40 cells
What are the exam components used to predict if a bitch is progressing and still in her fertile period?
Cytology
[Hormone]
Speculum examination
What do you need to avoid when performing a vaginal cytology?
Clitoral fossa
Clitoris
Urethral orifice
How should you direct your swab when performing a vaginal cytology?
a. Ventro-cranially
b. Dorso-cranially
c. Ventro-caudally
d. Dorso-caudally
b. Dorso-cranially
At which stage of the cycle are cells from a vaginal cytology fully cornified?
Estrus
At which stage of the cycle do cells from a vaginal cytology change from predominantly cornified to predominantly noncornified?
Diestrus
Which hormone dominates in proestrus?
Estrogen
T/F: During proestrus sex pheromones in vaginal secretions, anal sac secretions or urine attract males.
True
Attract males but not receptive
During which phase are the cells large and angular with small to no nuclei?
Proestrus
What is the shrinkage of cells called that can be observed in a sample from a bitch in estrus?
Crenulation
Which hormones peak during estrus?
LH
FSH
Vaginal cytology in estrus will generally show ___% cornified and ___% anuclear cells?
100
50
At what P4 level does the LH surge occur?
2.0
At which phase does the uterus develop remarkable tone?
Diestrus
Mammary development depends on/reflects which hormone?
Prolactin
Stage?
Proestrus
Stage?
Diestrus
Stage?
Estrus
____ peaks 24-47 hours into estrus and is caused by an ______ peak during proestrus.
LH
Estrogen
What type of oocyte does a bitch ovulate and in which phase is it?
Primary occyte (2N)
Prophase 1
In general, how long is a secondary occyte viable before becoming atretic if not fertilized?
3-4 days / 108 hours
Monitoring which hormone is the modern standard for breeding management? How often is it sampled?
Progesterone (P4)
Every other day
Start 3-4 days after proestrus or when vaginal cornification is 50% superficial and 20% anucleated cells
At which level of progesterone does ovuation begin? What is the level when it is complete?
- 0
- 0
A bitch should be bred _____ hours after ovulation for natural breeding.
24-72
A bitch should be bred _____ hours after ovulation for AI with chilled semen and ______ hours with frozen semen.
72-96
At least 96 hours
How long do embryos remain in the oviduct? What phase are they when they enter the uterus?
9-10 days
Late morula or early blastocyst
For how long are spermatozoa alive in the genital tract of the bitch with natural cover?
6 days
T/F: Conception rates are higher and litter sizes larger with AI.
False, natural is more successful
What is more definitive for breeding management, progesterone or LH assays?
LH
Given these values, when did the LH peak occur?
Tuesday
Given these P4 values, when should this bitch be bred with frozen semen?
Monday
How many progressively motile, morphologically normal spermatozoa should a male have for breeding? What percent should have normal morphology? What percent should have normal motility?
200 x 10^6
80%
80%
Whentaking testicular measurements, what should you avoid including?
Epididymus
What are the 3 fractions of ejaculate?
Pre-sperm
Sperm rich
Prostatic portion
Which drugs can be given for prior to manual stimulation to assist in ejaculation?
Oxytocin 5IU SQ/IM 5-10min before
Prostaglandin/ PGF2a 0.1mg/kg SQ/IM 15 min before
What’s this?
Mavic Canine AI Catheter
What methods can be used for insemination with frozen semen?
Transcervical or surgical
To ensure semen in uterus
T/F: Vaginal strictures are heritable.
False, developmental defect
Can a bitch with vaginal stricutres breed and birth normally?
No
Will require AI (which may be difficult) and C-section
What is superfecundation?
When 2 males breed the same female during a single estrus
Can a bitch experience superfetation?
No
Where female may be bred and get pregnant and then go through another receptive period and get pregnant again (fetuses of diferent ages) - can occur in rodents