SA - Manipulation of the Estrous Cycle Flashcards
What are the indications for induction of estrus?
Missing breeding opportunities, conception failure, treatment of primary or secondary anestrus (most common), and synchronization of ovulation for ET programs (research only)
Can we induce estrus in dogs?
Yes, but you need to respect the mandatory repair period in anestrus (90-150 days)
What can be used to induce estrus in dogs?
Synthetic estrogens, GnRH agonists, gonadotropins, and dopamine agonists
What synthetic estrogen can be used to induce estrus?
Diethylstilbesterol (DBS)
What GnRH agonists can be used to induce estrus?
Deslorelin*, Lutrelin, Buserelin, Fertirelin, and Leuprolide
What gonadotropins can be used to induce estrus?
LH, FSH, eCG, and hCG
What dopamine agonists can be used to induce estrus?
Cabergoline and bromocroptine
Is Diethylstilbesterol recommended? Why or why not?
Not recommended - the possible risks outweigh the benefits
What risks are associated with diethylstilbesterol use in inducing estrus?
Severe thrombocytopenia and aplastic anemia
What do GnRH agonists do to induce estrus?
They mediate the synthesis and release of LH and FSH from the anterior pituitary
What failure has been reported with GnRH agonist use to induce estrus?
Premature luteal failure which results in shortened diestrus and subsequent pregnancy loss
What Deslorelin implants can be used to induce estrus?
Suprelorin and Ovuplant - not approved in the US
Where are Deslorelin implants placed?
Subcutaneously either in the vulvular region or in the ventral abdomen
How quickly do Deslorelin implants work?
If given to an anestrus bitch, there will be reliable and rapid onset of estrus (7-10 days)
When should deslorelin implants be removed?
once ovulation is confirmed
What gonadotropins should not be used dogs because they show poor results?
LH and FSH
What side effects are associated with use of eCG?
Immune-mediated reactions, sudden death, and unpredictability of response
Are gonadotropins recommended for inducing estrus?
No because of the availability and side effects - not available in the US
What do dopamine agonists do to induce estrus?
They suppress prolactin secretion which shortens the duration of anestrus and will induce estrus if there is prolonged anestrus
What must precede induction of dopamine agonists?
anestrus - at least 120-150 days
Use of dopamine agonists may require ____ days of treatment?
30+ days
What dopamine agonists are available for dogs?
Cabergoline or Bromocroptine
What side effects are associated with Capergoline?
coat color changes and vomiting
What can induce estrus in cats?
FSH or hCG
What is the recommended drug of choice for inducing estrus?
dopamine agonists
What are the positives to using long acting preparations for inducing estrus?
convenient for owner and less stressful for the patient
What are the negatives to using long acting preparations to induce estrus?
Premature luteal failure and reduced pregnancy rates
What are the indications for inducing ovulation?
behavioral modification and artifical insemination
How can ovulation be induced in the queen?
with physical methods or hormonal methods
What physical methods could induce ovulation in the queen?
Mating with a vasectomized tom or inserting a sterile swab or gas rod into the vagina (must be repeated multiple times)
What hormonal methods can be used to induce ovulation in the queen?
hCG and GnRH
What are the indications for suppressing estrus?
Pets or working dogs
What are the surgical methods for suppressing estrus?
Ovariectomy and/or ovariohysterectomy
What are the non-surgical options to suppress estrus?
Mibolerone (androgen), Megestrol acetate (progestogen), or Deslorelin acetate (GnRH agonist)
When is suppression of estrus not recommended?
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
What are the adverse effects to suppressing estrus?
Cystic endometrial hyperplasia and pyomemtra
Breakthrough proestrus
Clitoral hypertrophy
Vaginitis
Increased activity of skin sebaceous glands
Mild epiphora
Alteration in hepatic function
What are the long term adverse effects of suppressing estrus?
Obesity, diabetes mellitus, and neoplasia of the uterus and/or mammary glands
If you want to suppress estrus using Mibolerone, when should treatment begin?
At least 30 days before the onset of estrus
What species is Mibolerone not approved for use in?
Queens - hepatotoxicity
It is also not readily available in the US
What can Megestrol acetate be used to do?
Stop the cycle or suppress the cycle
If you choose to use Megestrol acetate to stop the cycle, when will the subsequent estrus occur?
4-6 weeks earlier than expected
If you want to Megestrol acetate to suppress the cycle, when should it be given? When will subsequent estrus happen?
Should be given in late anestrus
Subsequent estrus is seen 2-9 months later
How can Deslorelin be given to suppress estrus?
You use it the same way that you use it to induce estrus, except you do not remove it after 7-10 days
How long can Deslorelin suppress estrus in a dog?
For up to a year
Remember it is not approved in the US
What are the indications for pregnancy termination?
Mis-mating or to maintain health of the female carrying the litter
How long should therapy for terminating a pregnancy be delayed?
Until the unwanted pregnancy is documented at ~30 days
What are the options for terminating a pregnancy?
Ovariohysterectomy, estrogens, prostaglandins, dexamethasone, cabergoline, and algepristone
What estrogens can be used to terminate a pregnancy?
Diethylstilbestrol and estradiol cypionate
Why is estrogen therapy to terminate pregnancy no longer recommended?
The risks outweigh the benefits - pyometra, irreversible aplastic anemia, and prolonged estrus
How do prostaglandins terminate pregnancies?
They induce luteolysis
What are the side effects of using prostaglandins to terminate pregnancies?
Vomiting, panting, cramps, excessive salivation and defecation
What prostaglandins can be used to terminate pregnancies?
Lutalyze and Cloprostenol
Misoprostol can be used
Can prostaglandin therapy be used in cats to terminate pregnancies?
yes
If you want to use dexamethasone to terminate pregnancies, when should pregnancy be confirmed?
At 30+ days via ultrasound
What adverse effects/clinical signs are associated with using dexamethasone to terminate pregnancies?
Vaginal bleeding, anorexia, panting, and PU/PD
Once abortion is confirmed, what must you do to the doses of dexamethasome?
taper the dose
What agent can be used to terminate late term pregnancy (>40 days)?
Cabergoline
What does cabergoline do?
It inhibits prolactin and can be highly efficacious in termination
Is cabergoline better tolerated in dogs or cats?
cats
What combination protocol for pregnancy termination is effective after 25 days of gestation?
Cabergoline, cloprostenol, +/- misoprostol
What is Algepristone?
a progesterone receptor blocker
Where is algepristone available?
In Europe, South America, and Australia
What clinical signs are associated with Algepristone?
minimal to none
How is Algepristone given?
as an outpatient medication
Approximately how long after administration of Algepristone does abortion occur?
30 hours after treatment
