Canine Estrous Cycle Flashcards
What is the significance of collecting swabs at the cervix?
Caudal to hymen: originates from ectoderm;
cranial to hymen: originates from mesoderm
T or F:
Pubertal bitches are less likely to demonstrate estrus when ovulation occurs.
True
What is a silent heat?
ovulation occurs in absence of proestrus-estrus behavior or signs
What is the timeframe for fertilization in the bitch?
9 days!
What is unique to the bitch’s cycle prior to ovulation with regard to hormone levels?
Pre-ovulatory follicles produce PROGESTERONE…
When do E2 levels peak in the bitch estrous cycle?
late proestrus
T or F:
Only in the bitch do you have a stage where there are high P4 and high E2 at the same time.
true; this happens when E2 is peaking
How long is anestrus typically in the bitch?
90-150+ days
{involution following diestrus is this long}
How long is the bitch’s cycle?
~5-7months
What do we call the time from the beginning of one estrus to beginning of next estrus?
interestrus period;
{larger dogs tend to have shorter interestrus period;
older dogs >8yo, tend to have longer interestrus period }
What is the minimum requirement for cycle length?
4 months;
fertility is low if <90day anestrus :(
During the luteal phase, what hormone dominates and is the dog pregnant or not?
progesterone;
could be pregnant or pseudopregnant
What is the maximum cycle length in the bitch?
12 months
{holdover from wild canids; 1 cycle/year}
If longer than 12 mo, investigate:
Hyperprolactemia?
T or F:
Cornification of vaginal epithelial cells accurately predicts time of receptivity, LH surge, or ovulation.
FALSE;
coordinate cytology, hormone concentration, & speculum examination
If you’re not pointing the swab up twd the tail/dorsum, what do we risk?
catheterization of the urethra
What type of cell is this?
Parabasal
{round or oval, large nucleus}
What type of cell is this?
Small-Lg intermediate cells
{larger than parabasal cells; borders irregular}
What type of cell is this?
Superficial cells
{largest seen, borders irregular, no nucleus present; fully cornified!}
What is the most likely stage this bitch is in?
- Late* Proestrus;
- suggest breeding in 4-5 days*
What are the behaviors of proestrus?
Non-acceptance of male dog;
- early*: negative responses; growling/snapping/aggression
- late*: passive responses; sits down when dog attempts mounting; tucks tail
What hormone dominates in proestrus?
Estrogen
What is the term for late, maximum shrinking of mucosa detected on vaginal speculum during estrus?
Crenulation
What stage?
Proestrus
During what stage do progesterone levels rise slowly then spike?!
estrus
What period of the estrous cycle is marked by a sharp decrease in superficial cells & increase in parabasal & sm.intermediate cells?
DIESTRUS
P4 peaks around how many days after the LH surge?
15-30 days
Hormonal profile of estrus in bitch?
E2: falling
P4: rising
LH & FSH: peaking!
Vaginal cytology of the bitch demonstrating RBCs & mixed epithelial cells would indicate what phase of estrous?
Proestrus
T or F:
The RSAT Brucella test is sensitive, but not specific.
True.
Mostly accurate when negative
Based on vaginoscopy/endoscopy, what phase is the best time to breed?
Angular {or declining…} Phase
If P4 was between 2.0-2.9ng/mL, when would you want to breed the bitch?
{LH surge is happening}
4-6 days
T or F:
dogs may undergo superfecundation, but not superfetation.
True.
When do Relaxin levels begin to rise during gestation in the bitch?
20-30 days
When is the fetal heart rate usually first detected via US?
23-25 days
norm: 200-250bpm
