Hormones in SA Fertility Control Flashcards
what are the hormonal options and pathway/specific actions for contraception
Progestagens (=progesterone and synthetic progestogens aka progestins)
- Suppress GnRH/LH pulses and the GnRH/LH surge in the female, thus follicle maturation, (proestrus) and ovulations
what are the progestagens used for canine contraception
- Medroxyprogesterone acetate (MPA): (Promone-E)
- Megestrol acetate (MA): (Ovarid)
- Proligestone: (Delvosteron)
how is proligestone (delvosterone) used long term
postponement of heat
Repeat injections given in anestrous induced by the previous injection
At 3, 4, 5 months then every 5 months
how is proligestone (delvosterone) used short term
A single injection given in anestrus
how is proligestone (Delvosterone) used to suppress heat after onset
Single injection given at the beginning of pro-estrus
Wait 5 days to 1 week until contact with entire male
how do the side effects of proligestone (delvosterone) compare to MA and MPA
less side effects
how is estrus suppression done in the queen
Very high fertility rate —> need to manage reproduction
Long or short term and reversible suppression possible with Progestins such as MPA, MA, proligestone
Use at lowest possible doses to reduce side effects
Other progestins available but less evaluated
Essential to advise owners of risks/benefits
how is megesterol acetate (MA) used in bitches
Oral, dogs/cats
Use at beginning of proestrus or anestrus
- Avoid during metestrus and diestrus (luteal phase)
Suppress estrus
Short acting compound in tablet form, daily administration
how is medroxyprogesterone acetate (MPA) used in bitches
Subcutaneous depot injection
Treat only anestrous bitches
- If not in anestrous will overdose with progesterone —> side effects
what are adverse side effects of progestogens
Cystic endometrial hyperplasia
Pyometra
Mammary hypertrophy and possibly mammary tumours
Weight gain
Diabetes mellitus
Adrenal suppression
- Megestrol acetate is used in cats for its corticoid activity in military eczema)
Coat and behavioural changes
when are progesterones contraindicated
diabetes mellitus
liver disease
mammary tumours
why would you want suppress fertility in male dogs
Puberty dependent on breed (size)
If sexual behaviour of the dog is not compatible with the environment but want to breed from him later
Several hormonal options available
Hormonal treatment is reversible and can be short or long term
- Reversibility is a bit more unpredictable after long term
Essential to advise owners of time to infertility following treatment, risks/benefits
what are the hormonal options and pathways/specific actions to suppress fertility in male dogs
All reduce testosterone (T) or actions of testosterone
- Progesterone negative feedback (synthetic progestogens)
- GnRH agonist-induced down regulation of LH and T
- Androgen receptor antagonist action
what are the options to suppress fertility using progesterone in male dogs
Delmadinone acetate SC or IM for dogs/cats (Tardak)
Megestrol acetate (Ovarid)
Osaterone tablets (Ypozane)
Rapid effects of T
what are the GnRH options to suppress fertility in male dogs
GnRH agonist incuded down regulation of LH and T
Deslorelin implant (Suprelorin)
how does Deslorelin implant (Suprelorin) work in male dogs
GnRH agonist (144x activity)
Occupies GnRH receptor constantly
Down regulates LH release
Reduces Leydig cell testosterone production
Long half life and high potency
how long does testosterone suppression take when using a deslorelin implant
Suppression of testosterone production takes 6-8 weeks
Reduced sperm production and motility
Infertility from 8 weeks-6 months (4.7mg) or 12 months (9.4mg) after insertion
what are the side effects of deslorelin implant
none
reversible but recovery can be unpredictable