Female Reproduction Flashcards
how many times a year do female dogs cycle
1-2x per year
what is considered day 0 of the female cycle
the day of the LH surge
what does day 0 allow you to predict
fertile window (days 3-4)
prediction of whelping
anestrus
not in heat or close to being in heat
can be 4-9 months long depending how many times the dog cycles in a year
NO hormonal influence
proestrus
increase in estrogen - starting to become under estrogen influence
lasts 8 days
males are interested but females are NOT receptive
estrus
“heat”
female becomes under the influence of estrogen
female is interested and receptive
estrogen starts decreasing, progesterone starts increasing
diestrus
luteal phase; occurs post ovulation
progesterone levels are HIGH
female is not receptive
lasts 3-4 months and either terminates in whelping (if go pregnant) or the CL dissipates after 9 weeks
what kind of cyclicity do cats have
seasonally polyestrous
several cycles during the breeding season only
what is the breeding season for cats
spring and summer (daylight >12 hr)
what kind of ovulators are cats
induced ovulators
- will ovulate during copulation
if cat is bred and fertilized during heat - what happens
induced LH surge –> ovulation –> pregnancy
if cat is bred but not fertilized - what happens
induced LH surge –> ovulation –> diestrus –> interestrus –> repeated proestrus + estrus cycles
if cat is not bred - what happens
interestrus –> repeated proestrus + estrus cycles
what does clinical ovulation timing allow you to do
ID the fertile window
accurately predict due date
benefits of clinical ovulation timing
able to use suboptimal semen (chilled, frozen, etc)
optimizes breeding efficacy
higher success rate
what diagnostics are used for ovulation timing
- vaginal cytology
- vaginoscopy
- serum hormone levels
main function of vaginal cytology
acts as a biomarker of ESTROGEN levels
function of vaginoscopy
determine when the ova are mature and most fertilizable based on the characteristics of the vaginal mucosa
function of performing serum hormone levels
progesterone and LH
can help determine ovulation date
role of estrogen
causes progressive thickening of the vaginal mucosa in preparation for mating
are blood estrogen levels or vaginal cytology and vaginoscopy a better indicator of estrogen effect
vaginal cytology + vaginoscopy is a more clinically relevant method of assessing estrogen levels
tells you when the dog is in heat and when to start running progesterone blood tests
do estrogen levels correlate with ovulation time or the fertilization window
NO - dependent on LH and progesterone
function of luteinizing hormone
triggers ovulation (LH surge)
how long after the LH surge does ovulation occur
24-36 hours
how long does egg maturation occur after LH surge
48-72 hours
how long does diestrus occur after LH surge
7-9 days
what is the gold standard test for identifying the fertile period
blood LH levels
BUT can be expensive and hard to catch sample on the correct day
what is the most applicable test to determine the day of the LH surge
blood progesterone levels
progesterone will start to INCREASE immediately after the LH surge - rise in progesterone indicates onset of ovulation
function of progesterone in dogs
causes preovulatory luteinization in DOGS only
does preovulatory luteinization occur in cats
no - only occurs in dogs
allows us to estimate the LH surge before it occurs by assessing a rise in progesterone
how to ID the fertile period using progesterone levels
progesterone increases at the time of LH surge - expect an increase starting once progesterone reaches 1.5-3.0 ng/mL
once progesterone reaches 1.5-3.0 –> repeat in 48 hours
repeat test should be >5 if ovulated
vaginal mucosa during proestrus
edematous, thickened vaginal mucosa
stimulated by estrogen
vaginal mucosa during estrus
“crenulated” - toughened mucosa due to decreased edema
BEST time to breed
preovulatory follicles on ultrasound
large follicles with hypoechoic fluid inside
ovulatory follicles on ultrasound
collapsed follicles with echogenic center
postovulatory follicles on ultrasound
CLs develop (thicker wall)
steps of performing ovulation timing
- perform cytology within 7 days of coming into heat (during proestrus)
- if still too early - repeat cytology every 2-4 days if still too early - perform serial hormone assays once there are >70-80% superficial cells on cytology
- progesterone every 48 hrs
- check for initial rise at 1.5-3.0 –> indicates day 0
- expect fertile period at day 3-7 - on breeding day (days 3-7) - repeat vaginal cytology + vaginoscopy to check for full cornification/crenulation
- follow up cytology to ID onset of diestrus to predict due date (count forward from day 1 of estrus)
what days of the cycle should natural breeding or fresh AI be used
days 3 and 5
or
days 4 and 6
> 96% conception rate
what days of the cycle should chilled semen be used
days 3 and 5
or
days 4 and 6
80% conception rate
what days of the cycle should frozen semen be used
days 5 and 6
or
day 6 alone
options for how to determine whelping date
- count from day 1 of diestrus
- count from day of LH surge
- count from breeding date (less reliable)
gestation length from day 1 of diestrus
56-58 days from day 1 of estrus
determined on vaginal cytology - <50% superficial cells; approx 7-9 days after LH surge
gestation length from day 0 (LH surge)
64-66 days regardless of breeding date
determined by the initial rise in progesterone
gestation length from breeding date
wide range - 58-72 days from first breeding
LESS ACCURATE - varies by estrual behavior and sperm longevity
steps of a prebreeding consultation
- PE - evaluate for conformational abnormalities
- temperament evaluation
- infectious disease screening
- discuss genetic screening by breed
- discuss breeding husbandry
- special studies - plan ovulation timing, discuss labor and C-section, discuss stud dog or tom cat
what infectious disease testing needs to be done prior to breeding
canine brucellosis on ALL females (ideally all males too) before breeding
vaginal cultures are NOT commonly done because normal growth of aerobic organisms and mycoplasma can be normal
effects of canine brucellosis
abortion
infertility
orchitis
epididymitis
testicular atrophy
meningitis
uveitis
discospondylitis
transmission of canine brucellosis
oral and venereal
does exposure to canine herpesvirus-1 on naive females guarantee antibody transfer to neonate
ONLY if exposed early in gestation prior to the LAST THREE WEEKS
if an unexposed female gets exposed to CHV-1 in the last 3 weeks of gestation - will not have enough time to generate antibodies to pass onto neonate
effects of naive neonates to CHV-1 during first 3 weeks
death most likely
CHV-1 screening
performed on the dam
if positive –> indicates sufficient maternal antibodies to pass onto the pup in colostrum
if negative –> dam should be quarantined for 3 weeks prior to whelping AND 3 weeks after whelping (with pups) to avoid contact with CHV in environment
is there a CHV-1 vaccine available in the US
no
what are the indications to terminate a pregnancy
- accidental breedings
- genetic disease
- pregnancy is contraindicated in that animal (ex. dam has a treatable disease but the treatment is contraindicated with pregnancy)
what to recommend to an owner that is concerned about an accidental breeding
NO intermediate interventions - early pregnancy is refractory to medical abortion
advise owner that majority of misbred dogs will not get pregnant
have to wait 25-30 days to do a pregnancy check with ultrasound
what is the window for medical or surgical termination of pregnancy
after day 35 of gestation
before day 49 of gestation (before 8th week)
methods of terminating a pregnancy
- surgical (OVH)
- medical - oral dexamethasone vs SQ prostaglandins
when is OVH abortion recommended
accidental pregnancies where the damn is not planned to be bred in the future
when are medical abortions indicated
dog plans to be bred in the future
surgery or anesthesia is contraindicated
medical abortion options
- PO dexamethasone - done at home
- SQ prostaglandin - done in hospital
side effects of medial abortion
galactorrhea - mammary development + milk due to reflex prolactin production
abbreviated diestrus - will come into heat sooner than expected
what should always be done after a medical abortion
post therapy ultrasound to confirm evacuation of the uterus
what test is used as a biomarker for estrogen levels
vaginal cytology
what phenomena occurs in female dogs that permits evaluation of the 12-24 hr LH surge
initial rise in progesterone due to preovulatory luteinization
functions of ovulation timing
- ID fertile window
- predict due date accurately
what infectious disease testing should be done prior to breeding
canine brucellosis
+/- CHV-1
window to terminate pregnancy
after day 35
before 8th week
medical therapies do NOT work early in gestation
