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Theriogenology > Canine Estrous Cycle, Vaginal Cytology, Breeding Mgmt > Flashcards

Canine Estrous Cycle, Vaginal Cytology, Breeding Mgmt Flashcards

1
Q

Puberty in dogs occurs ______

A

6-24 months (average age of 7-10 months)

- small dogs reach puberty earlier than big dogs

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2
Q

Canine seasonality

A

Non-seasonal monoestrus

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3
Q

What are the 4 stages of the estrous cycle?

A
  • protestrus
  • estrus
  • diestrus
  • anestrus
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4
Q

What are the sources of reproductive hormones?

A
  • estrogen: preovulatory follicle
  • progesterone: CL and some from adrenal
  • LH: pituitary
  • FSH: pituitary
  • GnRH: hypothalamus
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5
Q

GnRH

A

Causes release of FSH and LH

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6
Q

FSH

A

Stimulates preovulatory follicles

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7
Q

LH

A

Causes ovulation

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8
Q

Estrogen

A

initiates proestrus

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9
Q

Progesterone

A

Maintains pregnancy

- there is no placental takeover of progesterone in dogs!!

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10
Q

Behavioral changes

A
  • attractiveness
  • acceptance: when the female will stand for mating
  • posture: rigid stance, deflects tail to one side, elevate vulva
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11
Q

Physical changes

A
  • color: pale (anestrus) to pink
  • swelling: due to estrogen, causes Na retention in vulvar tissues
  • discharge: serosanginous, blood comes from the wall of the uterus (diapedesis)
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12
Q

Vaginal cytology

A

Percentage of cornification
- epithelial cells will cornify in response to high levels of estrogen –> are further from the blood supply due to swelling

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13
Q

Endocrine level

A

Identify LH surge directly or indirectly

- most accurate staging method

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14
Q

Proestrus

A

Bitch is attractive but not receptive

  • vulva begins to swell and discharge starts
  • vaginal cytology: intermediates, some cornified, RBCs
  • basal progesterone, rising estrogen
  • duration: 6-11 days (avg 9 days)!!!!
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15
Q

Estrus

A

Bitch is attractive and receptive

  • vulva is less turgid, straw colored discharged
  • vaginal cytology: all cells are cornified (80-90%)
  • progesterone rises from preovulatory lutenization, estrogen has peaked and is falling, LH surge
  • duration: 3-20 days (avg 5-9 day)!!
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16
Q

Diestrus

A

Bitch will no longer accept male

  • vulva reduces in size and discharge stops
  • vaginal cytology: intermediate, parabasal cells, lots of WBCs
  • CL produces large amounts of progesterone
  • duration: 57 days if pregnant, 60-100 days if not pregnant
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17
Q

Anestrus

A

Period of sexual quiescence

  • uterus is involuting and preparing for next cycle
  • behavior similar to spayed female
  • vaginal cytology: parabasal and intermediate
  • progesterone and estrogen are both low
  • duration: 2-9 months
18
Q

Proestrus averages ______

A

9 days

19
Q

Estrus averages _____

A

9 days

20
Q

LH surge triggers ovulation in ______

A

48 hours

- need to identify LH surge to determine when ovulation occurs

21
Q

Bitch ovulates primary oocytes over a period of _____

A

36 hours

- staggered release

22
Q

Each oocyte undergoes final phase of meiosis that takes ______

A

48 hours

23
Q

Eggs are fertilized in oviducts ______ after LH surge

A

4-5 days

24
Q

Fertilized eggs remain in oviduct for ______

A

8-10 days

25
Q

Embryos migrate to uterus by day ____

A

15

- implantation occurs

26
Q

______ supports pregnancy throughout gestation

A

CL!

27
Q

If you want to prevent implantation right after an accidental breeding, than give ______

A

Estrogen!

- prevents embryo from reaching the uterus by tightening the utero-tubular junction

28
Q

Breeding management

A
  • behavior of female
  • vaginal cytology
  • endocrine testing
29
Q

Vaginal cytology

A

Used to determine presence of estrogen

  • estrogen’s effect on vaginal epithelium
  • cornified cells –> estrogen levels are or recently were elevated
  • parabasal cells: estrogen levels are low
30
Q

Vaginal cytology technique

A
  • swab cranial vagina
  • roll on slide
  • stain with Diff-Quik
31
Q

What are limitations of vaginal cytology?

A

Used only to stage the estrous cycle

32
Q

Proestrus on cytology

A

Mixture of epithelial cells, some parabasal some intermediate

  • few superficial cells seen early, many seen late
  • RBCs seen throughout
  • percentage of cornified cells increases as proestrus progresses
33
Q

Estrus on cytology

A

Majority are cornified cells (90%), many anuclear

  • can see large numbers of bacteria
  • few RBCs or WBCs
34
Q

Diestrus on cytology

A

Abrupt return to parabasal and intermediate cells (occurs over 24 hours)

  • lots of WBCs
  • can see metestrum cells and foam cells
35
Q

Accuracy of timing depends on ______

A

Breeding situation

  • fresh semen can live in repro tract for 1 week
  • frozen semen will only live 12-18 hours
36
Q

Basics for the average bitch where live cover breeding will be supervised by the owner

A

Breed on 1st day of standing heat and every 2-3 days thereafter until bitch refuses mating

37
Q

If you are determining the fertile period, then breed _____

A

3-6 days after LH peak (1 day after ovulation)

38
Q

Progesterone testing

A

Progesterone levels will coincide with LH surge

  • RIA or in-house kit
  • should test every 2-3 days until ovulation is confirmed
39
Q

LH testing

A

Identify LH surge in serum sample

  • sendout or in-house kit (only gives positive/negative result)
  • must test often due to short duration of surge (18-24 hours)
40
Q

Progesterone values

A
  • P4 rising through 2.0 coincides with LH surge
  • P4 between 4-6 coincides with ovulation
  • P4 greater than 10 coincides with fertile period
  • always assure animal has ovulated prior to breeding!

LH surge –> ovulation –> fertile period

41
Q

Dogs will whelp ____

A

64-65 days from LH surge

- if you look at diestrus cytology, will whelp 57 days later

Theriogenology (25 decks)

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