Contraception in Female Domestic Animals Flashcards
1
Q
methods for controlling reproduction
A
- permanent: sterilants
- prevention of conception: contraceptives
- terminating pregnancy: abortifacents
2
Q
sterilization sx techniques
A
- OV: spay: ovariectomy, primarily LA
- OHE: ovariohysterectomy: spay: SA
- ovary-sparing in dogs
- tubal/oviductal ligation, not practical
3
Q
advantages of OHE
A
- permanent
- prevention of disease
- reduced risk of mammary cancer: can be eliminated if spayed prior to the third heat
4
Q
disadvantages of OHE
A
- decreased resting metabolic rate, obesity
- urinary incontinence: prevalence and risk is controversial
- maybe from reduced estrogen levels causing decreased urethral sphincter tone over time
5
Q
ideal characteristics of contraception
A
- safe
- highly effective
- convenient
- prolonged duration of activity
- inexpensive
- reversible ?
6
Q
progestins
A
- natural progesterone
- synthetic progestins: regumate, ovaban, depo provera
- anti progestins: RU-486
7
Q
megestrol acetate
A
- ovaban
- megestrol acetate
- suppression of estrus in dogs, daily orally, not recommended for pubertal estrus or more than 2 consecutive cycles
- contraindications: potentially pregnant dogs, history of neoplasia, DM, kidney disease
8
Q
side effects of ovaban/megestrol acetate
A
- increased appetitie with weight ain
- lethargy/restlessness
- mammary development (not neoplasia)
- pyometra
- adrenal suppression
don’t use long term because of endocrinopathies
9
Q
medroxyprogesterone acetate
A
- depo provera
- dog progestin contraceptive
- SIDE EFFECT OF MAMMARY TUMORS***
10
Q
what is the main side effect of medroxyprogesterone acetate/depo provera***
A
MAMMARY TUMORS
- weight gain
- adrenal suppression
- mild lethargy
- uterine disease/CEH/pyo
11
Q
horses progestins
A
- altrenogest/regumate: really common behaviorally to keep out of heat and cycling in general
- short or long term administration to block estrus and ovulation
- used in performance mares
- safe effective and minimal side effects
- approved by FDA
- other synthetic progestins not as effective
12
Q
what do progestins do negative feedback wise?
A
- suppresses LH secretion: don’t get LH surge = don’t get follicular development, prevents ovulation
12
Q
what do horse progestins do***
A
- blocks expression of behavioral estrus
- blocks secretion of LH from anterior pituitary = prevents development of large follicles, prevents ovulation
13
Q
depo provera in horses?
A
- not effective: doesn’t bind to progesterone receptor
- not recommended for use in horses: doesnt suppress estrus/block LH surge or prevent ovulation
14
Q
androgens
A
natural: testosterone: aqueous?
synthetic: mibolerone/cheque drops
15
Q
androgens biological action
A
- blocks expression of behavioral estrus: dogs
- inhibits secretion of gonadotropins: FSH and LH from anterior pituitary by negative feedback
16
Q
androgen products in dogs
A
- mibolerone (cheque drops), compounded
- approved for suppression of estrus in dogs
- must be instituted 30+ days before onset of next expected estrus
- orally, once daily for as long as estrus suppression is desired
- return to estrus after treatment is variable
17
Q
side effects of mibolerone
A
- androgens in dogs contraceptives
- cheque drops
- clitoral hypertrophy: testosterone effect
- vaginal discharge
- increased mounting and aggressive behaviors
- anal gland inspissation (thickening)
- body odor musky
- obestiy
- decreased incidence of CEH/pyo complex and neoplasia compared to progestins
18
Q
what is the most widely used drug for estrus suppression
A
mibolerone/cheque drops: androgens for dog contraceptives
keep on for no more than 6 mo at a time
19
Q
contraindications of mibolerone/cheque drops
A
- pregnant dogs
- pre pubertal dogs
- dogs with renal or hepatic disease
- potential abuse for human body builders
20
Q
GnRH contraceptive agents
A
agonists, antagonists, toxins
agonist: fully activates receptor and may bind with greater affinity
21
Q
GnRH agonists
A
- more potent than native GnRH
- down regulation of anterior pituitary
- large doses required
- internalization of receptors: reduced secretion of LH and FSH from anterior pituitary
- prevents follicular development and ovulation
22
Q
GnRH agonists meds in dogs
A
- slow release implants: nafarelin, deslorelin
- suppress estrus for up to 27 months in dog
- no long term adverse effects on fertility
23
Q
what are the side effects of GnRH agonists in dogs?
A
- induction of estrus in anestrus bitches within 1-4 weeks of treatment: “flare effect” before subsequent suppression = can cause them to come into heat
- can be prevented by simultaneous treatment with a progestin
24
T/F: GnRH agonists in dogs can cause them to come into heat
true
25
suprelorin
GnRH agonist
- causes coat changes
- time implantation important
26
GnRH agonists in dogs
leuprolide, atri gel in colorad
- 90 day sustained release formulation
- LH levels suppressed, ovulation prevented
- achieved 100% preventing pregnancy in mule deer
27
GnRH agonist summary in dogs **
- downregulation
- suppressing LH and FSH
- can be used in both sexes
28
GnRH vaccine
- GnRH is a lil tiny peptide hormone
- not immunogenic, cannot just inject it
- must be bound to a larger molecule/protein to make it immunogenic
- KLH, BSA: bovine serum albumin
to make immune system recognize it: will develop abs against both
29
GnRH vaccine MOA
- anti GnRH abs bind to circulating GnrRH
- prevents GnRH from binding to receptors on pituitary gonadotroph cells
- blocks production of gonadotropins: FSH and LH
- animal cannot ovulate, cannot come into heat
not blocking secretion, just blocking biological function
30
biological action of GnRH vaccine
- eventually get to below threshold level and animal can come back into cyclicity unless you booster
- effective in males and females
- animal doesn't come into estrus or cycle
31
approved GnRH vaccines
- improvac: pigs
- equity: horse
- canine gonadotropin releasing factor: dogs
32
what is the difference between giving GnRH for downregulation and vaccine?**
- GnRH vaccine: blocking action of GnRH to make animal immunogenic because it is too small to recognize it. titers last a year
- GnRH agonist: causes surges in LH and FSH, which will return feedback to pituitary which will shut off = reduction = suppression in repro function
33
zona pellucida vaccine
- zona pellucida: acellular glycoprotein matrix surrounding oocyte/embryo
- zona pellucida consists of 3 proteins in most species: ZP1, ZP2, ZP3
- ZP3 is sperm binding site: where sperm attach to
- block binding site = sperm cannot attach and fertilize
- porcine zona pellucida vaccine
34
difference between GnRH vaccine and ZP vaccine**
GnRH: shut down, doesn't cycle. creating immune response and antibodies
ZP: continue to cycle, don't fertilize and don't get pregnant. creating antibodies and immune response so that abs bind to protein on oocyte and sperm cannot bind
35
what is the downside of the zona pellucida vaccine?**
even though they aren't getting pregnant, they keep cycling
caused issue in feral horses and deer: activity of these animals increased and thus HBC increased, resource need increased, etc
36
T/F: animals with the zona pellucida vaccine will continue to cycle**
TRUE: provides challenges: even though they aren't getting pregnant, they keep cycling
caused issue in feral horses and deer: activity of these animals increased and thus HBC increased, resource need increased, etc
37
biological action of ZP vaccine
- fertilization prevented as long as antibodies present
- animals continue to cycle!!
- infertility can be associated with pathology
38
porcine ZP vaccine
- ZP collected from pig abattoirs
- ZP mixed with adjuvant
- most commonly used immunocontraceptive antigen for fertility control
- >70 species of wild mammals used
- effective in temporary contraception
39
advantages of ZP vaccine
- lasts for months
- duration dependent on immune response
- reversible when IgG levels decline
