SA - Manipulation of the Estrous Cycle

Question 1

What are the indications for induction of estrus?

Answer 1

Missing breeding opportunities, conception failure, treatment of primary or secondary anestrus (most common), and synchronization of ovulation for ET programs (research only)

Question 2

Can we induce estrus in dogs?

Answer 2

Yes, but you need to respect the mandatory repair period in anestrus (90-150 days)

Question 3

What can be used to induce estrus in dogs?

Answer 3

Synthetic estrogens, GnRH agonists, gonadotropins, and dopamine agonists

Question 4

What synthetic estrogen can be used to induce estrus?

Answer 4

Diethylstilbesterol (DBS)

Question 5

What GnRH agonists can be used to induce estrus?

Answer 5

Deslorelin*, Lutrelin, Buserelin, Fertirelin, and Leuprolide

Question 6

What gonadotropins can be used to induce estrus?

Answer 6

LH, FSH, eCG, and hCG

Question 7

What dopamine agonists can be used to induce estrus?

Answer 7

Cabergoline and bromocroptine

Question 8

Is Diethylstilbesterol recommended? Why or why not?

Answer 8

Not recommended - the possible risks outweigh the benefits

Question 9

What risks are associated with diethylstilbesterol use in inducing estrus?

Answer 9

Severe thrombocytopenia and aplastic anemia

Question 10

What do GnRH agonists do to induce estrus?

Answer 10

They mediate the synthesis and release of LH and FSH from the anterior pituitary

Question 11

What failure has been reported with GnRH agonist use to induce estrus?

Answer 11

Premature luteal failure which results in shortened diestrus and subsequent pregnancy loss

Question 12

What Deslorelin implants can be used to induce estrus?

Answer 12

Suprelorin and Ovuplant - not approved in the US

Question 13

Where are Deslorelin implants placed?

Answer 13

Subcutaneously either in the vulvular region or in the ventral abdomen

Question 14

How quickly do Deslorelin implants work?

Answer 14

If given to an anestrus bitch, there will be reliable and rapid onset of estrus (7-10 days)

Question 15

When should deslorelin implants be removed?

Answer 15

once ovulation is confirmed

Question 16

What gonadotropins should not be used dogs because they show poor results?

Answer 16

LH and FSH

Question 17

What side effects are associated with use of eCG?

Answer 17

Immune-mediated reactions, sudden death, and unpredictability of response

Question 18

Are gonadotropins recommended for inducing estrus?

Answer 18

No because of the availability and side effects - not available in the US

Question 19

What do dopamine agonists do to induce estrus?

Answer 19

They suppress prolactin secretion which shortens the duration of anestrus and will induce estrus if there is prolonged anestrus

Question 20

What must precede induction of dopamine agonists?

Answer 20

anestrus - at least 120-150 days

Question 21

Use of dopamine agonists may require ____ days of treatment?

Answer 21

30+ days

Question 22

What dopamine agonists are available for dogs?

Answer 22

Cabergoline or Bromocroptine

Question 23

What side effects are associated with Capergoline?

Answer 23

coat color changes and vomiting

Question 24

What can induce estrus in cats?

Answer 24

FSH or hCG

Question 25

What is the recommended drug of choice for inducing estrus?

Answer 25

dopamine agonists

Question 26

What are the positives to using long acting preparations for inducing estrus?

Answer 26

convenient for owner and less stressful for the patient

Question 27

What are the negatives to using long acting preparations to induce estrus?

Answer 27

Premature luteal failure and reduced pregnancy rates

Question 28

What are the indications for inducing ovulation?

Answer 28

behavioral modification and artifical insemination

Question 29

How can ovulation be induced in the queen?

Answer 29

with physical methods or hormonal methods

Question 30

What physical methods could induce ovulation in the queen?

Answer 30

Mating with a vasectomized tom or inserting a sterile swab or gas rod into the vagina (must be repeated multiple times)

Question 31

What hormonal methods can be used to induce ovulation in the queen?

Answer 31

hCG and GnRH

Question 32

What are the indications for suppressing estrus?

Answer 32

Pets or working dogs

Question 33

What are the surgical methods for suppressing estrus?

Answer 33

Ovariectomy and/or ovariohysterectomy

Question 34

What are the non-surgical options to suppress estrus?

Answer 34

Mibolerone (androgen), Megestrol acetate (progestogen), or Deslorelin acetate (GnRH agonist)

Question 35

When is suppression of estrus not recommended?

Answer 35

``` Prior to or during the first estrus For females primarily used for breeding During pregnancy During pseudopregnancy To begin treatment during diestrus For females with uterine hemorrhage For diabetic patients For females with a prolonged heat ```

Question 36

What are the adverse effects to suppressing estrus?

Answer 36

Cystic endometrial hyperplasia and pyomemtra Breakthrough proestrus Clitoral hypertrophy Vaginitis Increased activity of skin sebaceous glands Mild epiphora Alteration in hepatic function

Question 37

What are the long term adverse effects of suppressing estrus?

Answer 37

Obesity, diabetes mellitus, and neoplasia of the uterus and/or mammary glands

Question 38

If you want to suppress estrus using Mibolerone, when should treatment begin?

Answer 38

At least 30 days before the onset of estrus

Question 39

What species is Mibolerone not approved for use in?

Answer 39

Queens - hepatotoxicity It is also not readily available in the US

Question 40

What can Megestrol acetate be used to do?

Answer 40

Stop the cycle or suppress the cycle

Question 41

If you choose to use Megestrol acetate to stop the cycle, when will the subsequent estrus occur?

Answer 41

4-6 weeks earlier than expected

Question 42

If you want to Megestrol acetate to suppress the cycle, when should it be given? When will subsequent estrus happen?

Answer 42

Should be given in late anestrus | Subsequent estrus is seen 2-9 months later

Question 43

How can Deslorelin be given to suppress estrus?

Answer 43

You use it the same way that you use it to induce estrus, except you do not remove it after 7-10 days

Question 44

How long can Deslorelin suppress estrus in a dog?

Answer 44

For up to a year Remember it is not approved in the US

Question 45

What are the indications for pregnancy termination?

Answer 45

Mis-mating or to maintain health of the female carrying the litter

Question 46

How long should therapy for terminating a pregnancy be delayed?

Answer 46

Until the unwanted pregnancy is documented at ~30 days

Question 47

What are the options for terminating a pregnancy?

Answer 47

Ovariohysterectomy, estrogens, prostaglandins, dexamethasone, cabergoline, and algepristone

Question 48

What estrogens can be used to terminate a pregnancy?

Answer 48

Diethylstilbestrol and estradiol cypionate

Question 49

Why is estrogen therapy to terminate pregnancy no longer recommended?

Answer 49

The risks outweigh the benefits - pyometra, irreversible aplastic anemia, and prolonged estrus

Question 50

How do prostaglandins terminate pregnancies?

Answer 50

They induce luteolysis

Question 51

What are the side effects of using prostaglandins to terminate pregnancies?

Answer 51

Vomiting, panting, cramps, excessive salivation and defecation

Question 52

What prostaglandins can be used to terminate pregnancies?

Answer 52

Lutalyze and Cloprostenol | Misoprostol can be used

Question 53

Can prostaglandin therapy be used in cats to terminate pregnancies?

Answer 53

yes

Question 54

If you want to use dexamethasone to terminate pregnancies, when should pregnancy be confirmed?

Answer 54

At 30+ days via ultrasound

Question 55

What adverse effects/clinical signs are associated with using dexamethasone to terminate pregnancies?

Answer 55

Vaginal bleeding, anorexia, panting, and PU/PD

Question 56

Once abortion is confirmed, what must you do to the doses of dexamethasome?

Answer 56

taper the dose

Question 57

What agent can be used to terminate late term pregnancy (>40 days)?

Answer 57

Cabergoline

Question 58

What does cabergoline do?

Answer 58

It inhibits prolactin and can be highly efficacious in termination

Question 59

Is cabergoline better tolerated in dogs or cats?

Answer 59

cats

Question 60

What combination protocol for pregnancy termination is effective after 25 days of gestation?

Answer 60

Cabergoline, cloprostenol, +/- misoprostol

Question 61

What is Algepristone?

Answer 61

a progesterone receptor blocker

Question 62

Where is algepristone available?

Answer 62

In Europe, South America, and Australia

Question 63

What clinical signs are associated with Algepristone?

Answer 63

minimal to none

Question 64

How is Algepristone given?

Answer 64

as an outpatient medication

Question 65

Approximately how long after administration of Algepristone does abortion occur?

Answer 65

30 hours after treatment