Canine Estrous Cycle, Vaginal Cytology, Breeding Management Flashcards
When do dogs come into puberty?
6-25 months; average 7-10 months
What is the seasonality of canine reproduction?
Non-seasonal monoestrus
What are the 4 stages of the canine estrous cycle?
Proestrus
Estrus
Diestrus
Anestrus
When does the level of progesterone start to rise?
Towards the middle to end of proestrus when estrogen starts to drop
What causes the surge in LH?
The rise in P4 and the fall in estrogen
What does progesterone come from?
Preovulatory lutenization
What is the source of estrogen?
Preovulatory follicles
What is the source of progesterone?
CL and some from adrenal glands
What is the source of LH?
Pituitary
What is the source of FSH?
Pituitary
What is the source of GnRH?
Hypothalamus
Why is the progesterone level of a spayed dog low rather than absent?
Adrenal glands produce P4 also
What does GnRH do?
Causes the release of FSH and LH
What does FSH do?
Stimulate preovulatory follicles
What does LH do?
Causes ovulation
What does estrogen do?
Initiates proestrus
What does progesterone do?
Maintains pregnancy
Does the dog have placental take-over of progesterone?
No
How can you stage the estrous cycle?
Behavioral changes
Physical changes
Vaginal cytology
Endocrine levels
What are behavioral changes during estrous?
Attractiveness
Acceptance
Posture
What are physical changes during estrous?
Color
Swelling
Discharge
What does vaginal cytology show during estrous?
Percentage of cornification
What does the endocrine levels show during estrous?
The LH surge directly or indirectly
What is the color of the vagina/vulva in estrus? Anestrus?
Pink in estrus
Pale in anestrus
What does swelling of the vagina or vulva come from?
Influx of water due to the increase in sodium
What do cells of the vagina cornify based on?
Estrogen level
Cornification occurs when estrogen is high
What is the bitch like during proestrus?
Attractive, but not receptive
What happens to the vulva during proestrus?
Vulva begins to swell and discharge commences
What does vaginal cytology show during proestrus?
Predominance of intermediate cells, some cornified cells, and RBCs
What are the progesterone and estrogen levels during proestrus?
Progesterone level is basal
Estrogen level is rising
What is the duration of proestrus?
6-11 days, average of 9 days
What is the bitch like during estrus?
Attractive and receptive
What is the vulva like during estrus?
Less turgid, discharge changes to straw colored