Sm An - The Estrous Cycle

Question 1

what are ovaries covered by

Answer 1

ovarian bursa

Question 2

where is semen deposited

Answer 2

fornix

Question 3

what is a pseudocervix

Answer 3

dorsal median fold of tissue between vaginal wall and cervix

Question 4

how long does it take eggs to mature

Answer 4

48 hours on average

Question 5

canine oocyte lifespan and breeding

Answer 5

Canine oocytes have longer lifespan → extends the breeding period but fertilization can only occur once
the oocytes are mature

Question 6

when do progesterone levels start to rise

Answer 6

prior to ovulation

Question 7

what can you use progesterone for

Answer 7

to determine when ovulation occurs

Question 8

four stages of the canine estrus cycle

Answer 8

proestrus, estrus, diestrus, anestrus

Question 9

what stages of the estrus cycle make up heat

Answer 9

proestrus and estrus

Question 10

what is puberty

Answer 10

when the first proestrus occurs

Question 11

can you breed on the first heat

Answer 11

NO

Question 12

what is split heat

Answer 12

heat starts then stops without ovulation. Starts again later

Question 13

what is silent heat

Answer 13

very little vaginal discharge.

Question 14

when does puberty usually occur

Answer 14

Occurs earlier in small breeds vs. large breeds
◦ Average 8-14 months (range 6 – 26 months)

Question 15

four methods to determine stage of estrus

Answer 15

-vaginoscopy
-vaginal cytology
-progesterone levels
-behaviour/receptivity

Question 16

length of proestrus

Answer 16

9 days (0-27d range)

Question 17

when is day 1 of heat

Answer 17

first drop of blood

Question 18

what indicates estrogen levels are rising

Answer 18

Edema of vaginal epithelium; edema of the vulva

Question 19

external cues of proestrus (3)

Answer 19

◦ Swollen vulva
◦ Serosanguineous vaginal discharge
◦ May start “flagging

Question 20

state of progesterone during proestrus

Answer 20

Progesterone = low = baseline

Question 21

behaviour of bitches during proestrus (3)

Answer 21

*Bitches are typically not receptive yet
*Bitches may mount other bitches
*Bitches in heat may become aggressive towards other bitche

Question 22

what will you see on a vaginal cytology during proestrus

Answer 22

parabasal cells and intermediate cells

epithelium goes from 5-10 layers to 10-20 layers

Question 23

length of estrus

Answer 23

9 days (4-24d range)

Question 24

what happens during estrus

Answer 24

Stage at which LH surge occurs, ovulation occurs and fertile period occurs = when breeding occurs “standing heat”

Question 25

estrogen levels and progesterone levels in estrus

Answer 25

-Estrogen levels elevated initially; peak; starts decreasing at LH -Progesterone levels start to rise at LH, continue to elevate at ovulation & remain elevated

Question 26

what can we use to estimate the LH surge

Answer 26

progesterone

Question 27

when would we use an in house LH test

Answer 27

◦ Usually reserved for important breedings; frozen semen breedings

Question 28

when does LH surge occur

Answer 28

48hr before ovulation

Question 29

what is crenulation

Answer 29

Edema of vaginal epithelium decreases

Question 30

what happens to the vulva during estrus that we can see

Answer 30

Vulva becomes less turgid as estrogen decreases, serosanguineous discharge can diminish, can become lighter

Question 31

what behaviour will females do during estrus

Answer 31

Female should be receptive to male during fertile period ◦ Flagging ◦ Seeks out the male

Question 32

what cells do you see in vaginal cytology during estrus

Answer 32

cornified epithelial cells

Question 33

when do estrogen levels peak

Answer 33

estrus

Question 34

length of diestrus

Answer 34

2 months (56-58 days if pregnant, 56-90 days if not pregnant)

Question 35

will bitches be receptive to breeding during diestrus

Answer 35

no bc no longer in heat

Question 36

when does diestrus occur

Answer 36

6 days after ovulation, or 8 days from the LH surge

Question 37

what happens to the vulva during diestrus

Answer 37

Vulva diminishes in size, vaginal discharge subsides, vaginal epithelium flattens

Question 38

levels of estrogen and progesterone during diestrus

Answer 38

Period of time when progesterone is high; estrogen is low

Question 39

what do you see on vaginal cytology during diestrus

Answer 39

◦ Parabasal cells ◦ Intermediate cells ◦ Neutrophils

Question 40

layers of vaginal epithelium during diestrus

Answer 40

2-4 cell layers

Question 41

how do you tell the difference between proestrus and diestrus

Answer 41

progesterone levels!

Question 42

length of anestrus

Answer 42

4 months (range 4-12 months)

Question 43

when does anestrus occur

Answer 43

after diestrus

Question 44

progesterone levels during anestrus

Answer 44

it drops! luteolysis

Question 45

anestrus is a period of _____ ______

Answer 45

reproductive quiescence

Question 46

what is anestrus an important stage for

Answer 46

Important stage for uterine involution ◦ Uterine involution is a necessary process

Question 47

are bitches receptive to breeding during anestrus

Answer 47

no

Question 48

what does the vulva look like during anestrus

Answer 48

vulva small, no vaginal discharge

Question 49

why is a reproductive consultation important (2)

Answer 49

-Our responsibility to educate clients on responsible breeding -->Time commitment -->$$$ -Should only be breeding mature, healthy, good dogs -->Clearances -->Representative of the breed

Question 50

what is included in breeding bitch management (4)

Answer 50

-hx (medical and reproductive) -PE -repro exam (digital palpation, vaginoscopy, vaginal swab for cytology) -serum P4 levels (usually blood taken every 2 days)

Question 51

what status do we need to know for breeding bitch managemnet

Answer 51

brucella canis status

Question 52

breeding methods (4)

Answer 52

-natural -vaginal AI -transcervical insemination (semen deposited directly in uterus, can usually do without sedation) -surgical insemination (semen deposited directly in the uterus, more invasive than TCAI

Question 53

three types of semen that can be used in canine breeding

Answer 53

-fresh (can breed with standard vaginal AI, MAVIC catheter or TCAI) -fresh chilled (semen collected, stored in cool place, shipped) -frozen (TCAI or SAI only, progesterone timing required every 2 days, more in depth timing is required)