Infertility in the bitch Flashcards
Most bitches are not infertile, instead they
have not been bred properly/bad breeding management.
❖ What environment does the bitch live in
❖ How is it fed
❖ What is the general health of the bitch
Length of estrus/ length of inter estrus interval/bleeding history/ receptivity (start/end)/ determination of breeding time?
→pregnancy diagnosis, how and when
→previous pregnancies, normal deliveries, abortions, resorptions, c-sections, litter size
→male infertility: has the same sire been used or different, has the semen quality been checked, has he produced litters?
→ Brucella Canis status of the male and female (depending on which country)
Possible reasons for infertility (7)
- Inappropriate estrus control
- Failure to show estrus
- Abnormal estrus cycle length
- Abnormal mating
- Apparently normal mating but infertility
- Pregnancy failure
- Male infertility
From the history it´s important to determine whether the cycles are normal and if breeding management is done properly.
The most important reason for no pregnancy or small litters is?
Inappropriate planning of the optimal time of mating.
Failure to show estrus.
Primary problem: no estrus activity before 24 months of age (delayed puberty).
Describe reasons for this. (6)
❖ Normal breed variation( large breeds at much older age than small breeds when they reach puberty)
❖ Illness or underweight
❖ Inadequate observation of the owner or ”silent estrus”→ detection of progesterone (>2 ng/ml)→ look at the vulva lips
❖ Abnormal sexual differentiation → do karyotyping→ remove the gonads
❖ Ovarian agenesis/aplasia → rare condition→ can have increased FSH/LH→
laparotomy
❖ Previous ovarioectomy→ look for spay scars→ LH-test/AMH-test, GnRH stimulation test
Treatment of failure to show estrus.
If no underlying abnormalities have been detected, it’s possible to induce estrus by: (2)
- Administration of dopamine-agonist (cabergoline) → inhibits synthesis of prolactin, give daily until the first day of vulvar serosanguinous discharge → for up till 30 days (about 75% of the bitches will show estrus signs). Usually the same pregnancy rate as for a normal cycle.
- Deslorelin implant (GnRH agonist) → fast response in most cases. Remember to remove the implant, when the bitch has ovulated or else negative feedback from the ovaries to the release of gonadotropins will increase risk of resorption of early pregnancy.
Explain Estrus induction by GnRH agonists.
Deslorelin/Suprelorin stimulates gonadotropin secretion → induces follicular growth → the bitch comes into heat.
Implants:
❖ 4,7 mg deslorelin
❖ 9,4mg deslorelin
Implant is placed in anestrus → most bitches comes into heat very fast (few days later).
About 20% of the bitches don’t ovulate → remember to tell the owner this.
Pregnancy rate up to 70% (if treated in late anestrus)
Put the implant paraumbilical → remove it when the bitch has ovulated! Monitor the bitch for luteal insufficiency.
Explain Estrus induction by Cabergoline (Galastop).
Cabergoline is a dopamine agonist → lowers the secretion of prolactin→
increases the secretion of gonadotropins→ induction of estrus with 5 µg/kg SID (better to split in half → minimizes nausea).
Treatment for max 4 weeks.
If no estrus→ wait about a week and put in a deslorelin implant.
What is the physiological mechanism behind body temperature drop in females dogs going into labor?
Progesterone also has a thermogenic effect, meaning it helps to maintain the body’s basal temperature at a slightly elevated level.
With the drop in progesterone, the thermogenic effect is lost. This leads to a drop in the dog’s core body temperature, typically falling from the normal range of about 101–102.5°F (38.3–39.2°C) to around 98–99°F (36.7–37.2°C).
This decrease in body temperature is a physiological indicator that labor will start soon.
Describe Prolonged inter estrus interval – more than 12 months. Why?
What is normal?
Normal inter estrus interval is 6-7 months.
Some breeds shorter: German shepherd, Rottweiler (4-5 months)
Some breeds longer: golden retriever, ridgeback’s, basenji’s (up to 12 months)
Apparent prolonged estrus interval could be due to inadequate observation by the owner → do weekly vaginal smears to document the onset of proestrus (the estrogenic phase).
Prolonged luteal phase is extremely rare that progesterone production continues for more than 65 days → more likely to be ovarian disease (CL cysts or a progesterone-secreting granulosa cell tumor)
Describe Short inter estrus intervals. (5)
Could be due to:
split estrus,
ovulation failure,
short luteal phase,
short anestrus
ovarian cysts or tumors producing estrogen
Describe Split estrus: (3)
❖ Short interval (2-12 weeks) between clinical signs of proestrus
❖ Common in young bitches (follicle growth, but the follicles regress prior to ovulation)
❖ No treatment, the bitch will go into normal estrus after some weeks.
Describe Ovulation failure:
❖ No ovulation →
no luteal phase →
estrus occurs 2 months later.
❖ Appears in approximately 1% of estrus cycles.
Treat using:
500 IU of hCG IM every day for 3 days, induces luteinization of the follicles
→ GnRH- first injection
→ second injection after 90 minutes, afterwards 6 injections every 12 hours.
Describe Short luteal phase (hypolutheodism) causing Short inter estrus interval.
After ovulation you have inadequate production of progesterone.
Diagnosed by serial plasma progesterone showing lower values than expected and
a return to basal 20-40 days post-ovulation (normal should be high for 65 days (diestrus)).
Describe Short anestrus causing Short inter estrus interval.
Is normally seen in kennels with more bitches living together as a bitch in estrus will hasten another one into estrus.
Remember the uterus needs at least 4 month to normalize between to estruses.
If pro-estrus or estrus are prolonged:
If ovulation has not occurred by as late as 30 days after the onset of proestrus, this may be associated with (2)
tx?
failure of adequate LH production or insufficient LH receptors.
Treatment: HcG or GnRh
Remember that there is a big variation in the time of ovulation from the first day of
vulva bleeding between bitches and in the same bitch between different estrus
periods.
Describe Follicular cysts:
symptoms
diagnosis
complications
therapy
Symptoms:
Estrus behaviour for more than 30 days
Short interestrus interval
Diagnosis:
Do vaginal cytology
Ultrasound→ usually large (8-12 mm) thin walled, fluid filled
Complications:
Estrogen intoxication
Pyometra
Therapy:
❖ hCG (500IU/bitch) for 3 days
❖ GnRH
❖ Most effective is to ovariectomize or remove the cyst surgically.
Describe Estrogen-producing ovarian tumors resulting in estrus behavior. (5)
Mostly granulosa cell tumors (GCT) (but not commonly found)
Are often very large
Produce estrogen (and progesterone maybe?) → clinical signs of persistent estrus.
Diagnosis:
❖ Ultrasound: easy to diagnose → solid but with fluid filled cavities.
Therapy:
❖ Ovariohysterectomy
Describe behavioral problems with mating. (4)
❖ Dog that may have had bad experience with previous matings.
❖ The bitch has been presented for mating at a wrong time in estrus or a very dominant male dog.
❖ Poor social skills or not feeling very confident.
❖ The two dogs are ”friends living in the same kennel” can be difficult for them to mate.
Most common Abnormalities in the reproductive tract. (2)
Vestibulovaginal bands (vaginal septum)
Circumferential fibrous constriction
Describe Vestibulovaginal bands (vaginal septum). (4)
Failure of the complete fusion of the paramesonephric ducts in embryogenesis.
The septum can be a thin membrane at the vestibulovaginal junction, or it can result in a double vagina.
Dorsoventral directed fibrous band.
Thin ones are very easy to cut in sedation and the bitch can be bred without
problems in the same estrus.
Describe Circumferential fibrous constriction. (2)
Anatomical abnormality that may cause infertiliy.
If very tight and the diameter of the
cingulum is too narrow the bitch should not be bred or go for AI.
Always do digital vaginal exploration and vaginoscopy before mating!
Normal mating but no pregnancy? (4)
If a subclinical uterine infection is present it may cause a bad environment for sperm and eggs, or it can cause early embryonic death.
❖ More studies needed to clarify the numbers of infertile cases due to this problem.
❖ Cystic endometrial hyperplasia (CEH), develops because of the influence of progesterone on the endometrium
during diestruses – often seen in elderly bitches and can cause implantation failure after conception.
❖ Allowing persistence of commensal vaginal bacteria within the uterus → risk of pyometra.
Describe Vaginitis. (4)
Vagina holds a large amount of different bacterial cultures. All bacteria is a potential pathogen → uterine infection.
Infection in the vagina changes the pH, infiltration with white blood cells→
bad environment for the spermatozoa.
Cytologically a vaginal smear can be characteristic if it´s an acute vaginitis, but
not if it is chronic. Always do vaginoscopy anyway.
Opportunistic pathogens in the vagina:
E.Coli
Streptococcus
Stafylococcus
Pseudomonas
Mycoplasma and more
Bacterial examination of the female tract. (5)
Bacteriological samples can be taken at day 5-7 of proestrus (cervix needs to be a little open) from the cranial vagina (not from vestibule) and from the uterus using endoscopic techniques (to avoid contamination from the vagina).
Do bacterial analysis if infertility, resorptions, abortions etc.
If cytology shows toxic neutrophils and high count of bacteria. And if vaginoscopy shows inflammation.
For Mycoplasma spp → send the material to a special lab for differentiation of subspp.
Do uterine flush for deeper sample.
