Final: Mare cycle and breeding; Non-pregnant mare Flashcards
Descibe the cervix of a receptive mare.
Short and soft
Like a wilted rose
The dorsal commisure of the vulva should be at the level of the _________.
Ischial arch
A second degree _____________ is a common, frequently overlooked and serious lesion that is easily corrected.
Perineal laceration
What part of the anatomy helps create a seal between the vestibulum and the vagina?
Perineal body
On US evaluation of the repro tract, in which orientation are the uterine body and uterine horns viewed?
UB: Longitudinal
UHs: Cross-section
What is the ideal month for a foal destined to be racehorse to be born in?
January
Follicles formed during the transition period are
a. steroidogenically incompetenet
b. enlarged
c. steroidogenically competent and form estradiol
d. hyperfertile
a. steroidogenically incompetenet
How many waves do most horses have in their estrus cycle?
2
How much do follicles grow per day? What hormone reduces the growth rate of follicles?
3mm/day
Progesterone
At what size do follicles develop ovulatory capacity?
35mm
Ovulation occurs in response to rising ___ levels that peak ___ days after ovulation.
LH
Two
Which order is correct?
a. Follicle -> Ovulation -> Corpus luteum -> Corpus hemorrhagicum
b. Follicle -> Ovulation -> Corpus hemorrhagicum-> Corpus luteum
b. Follicle -> Ovulation -> Corpus hemorrhagicum-> Corpus luteum
The sperm revervoir in the uterine tube is adequate by ___ hours/days after breeding or insemination. These sperm remain viable for at least ___ hours/days.
4 hours
2 days
Occytes degenerate by ____ hours/days post-ovulation. This is why insemination should occur ____(prior to/ after) oculation.
12-16 hours
Prior to
When do fertilized embryos enter the uterus?
By 5.5 days after fertilization
What are the 2 requirements for inducing ovulation? What 2 agents can be used?
Must be in estrus and have a growing pre-ovulatory follicle at least 35mm large
hCG and GnRH
Why can administering hCG cause anaphylaxis?
Can cause production of autoantibodies
What is Deslorein accetate?
Long-acting injectable GnRH
What account for the difference in when the mare will ovulate when giving hCG (36hrs) and GnRH (42hrs)?
hCG = LH -> goes straight to ovary
GnRH -> Pituitary -> releases LH -> ovary
What are the side effects of Dinoprost (Lutalyse)?
Sweating
Colic
Depression
Prostaglandin labeled for horses (Cloprostenol/Estrumate is extra-label)
On what does the interval between PGF2a administration and estrus or ovulation depend?
Follicle size
- <25mm = 7-10d*
- >25mm = 3-5d*
- >35mm= 1-4d*
What is the most common exogenous P4 product for horses?
Regu-Mate(tm)
(Altrenogest)
How does a GnRH implant prevent estrus?
Superstimulation of GnRH receptors -> receptors internalize -> cannot be stimulated anymore
What is the best way to determine whether a mare is receptive?
Teasing with a stallion
How long does capacitation within the female repro tract take?
6 hours
This means it cannot immediately fertilize oocytes
If you are performing AI on a mare and inseminating her very close to or right at ovulation, what type of semen are you using?
Frozen
Immediately fertile but doesn’t last as long
Match the following types of semen with the expected rate of impregnation:
Fresh
Cooled
Frozen
50%
60%
70%
Fresh 70%
Cooled 60%
Frozen 50%
How many 0.5mL straws are one dose of cryopreserved semen?
Eight
800 million to 1 billion semen
How many progressively motile sperm is needed per dose of cryopreserved semen?
240 million
30% PM
What is a ‘test freeze’? When can you not test freeze?
Testing the various sperm extenders with a stallion’s collected semen to determine which is most compatible
Can’t test freeze if extracting epididymal sperm (e.g. after stallion’s death or castration; within 24 hours of testicle death)
How often should a mare be examined via US before AI?
Every 6 hours
So can inseminate as soon as ovulation is detected
How many hours after deslorelin administration should you AI a mare? Single dose vs split/double dose?
If single dose: 32-33 hours
Split dose (2 inseminations): 36-48 hours
T/F: The endometrial reaction to fresh semen is more exaggerated than to frozen-thawed semen.
False
Much more severe with frozen semen
Seminal plasma modulates response (not much in frozen) and during the freeze-thaw some of the sperm rupture releasing foreign antigens
How can you improve the outcome with low dose insemination?
Inseminiate into the deep horn
What is being described:
Stain semen with DNA dye
Put through flow cytometer in single file and in the correct orientation
Shine laser on the sperm and assess fluorescence
Sexing semen
Does not work well in horses, good in cows
Why is prostaglandin given to the donor mare after embryo recovery?
To make sure she is not pregnant
Also recheck because prostaglandin may not be effective
Is surgical or non-surgical embryo transfer more successful?
Non-surgical
T/F: In vitro fertilization is a common practice in horses.
False, doesn’t work well in horses
What is ICSI? When is it attractive, despite it being expensive?
IntraCytoplasmic Sperm Injection
When semen is extremely limiting
What is the pregnancy rate per cycle for intracytoplasmic sperm injection?
5-10%
What cells are usually used for cloning?
Fibroblasts
What are the 3 main physical barriers to uterine infection?
Vulva and perineal body
Vestibulovaginal junction
Cervix
How is cervical integrity best assessed?
(Vaginal) Palpation
What are the most commonly culutred bacteria found on an endometrial biopsy?
- E. coli*
- Streptococcus* spp.
What type of swab is best for endometrial cytology?
Brush
How many % neutrophils on endometrial cytology indicates impaired infertility?
2
What causes eosinophils in an endometrial cytology sample (2 things)?
Air
Urine
What does an endometrial biospy reveal that cytology cannot?
Whether there is fibrosis in the uterus (irreversible changes to the uterus) which impairs fertility
What are cysts in the uterus of a mare? Bitch?
Mare: Dilated lymphatics
Bitch: Dilated endometrial gland
What is the main strategy for hastening the onset of the breeding season?
Artifical lighting
Start in November for cycling in late February
What hormone can be given to inhibt GnRH? What can be given to increase GnRH? What unwanted side effect can administering this cause?
Dopamine
Sulride, Domperidone
Can cause lactation
What does an irregular inner surface of the granulosa across from the ovulation fossa, aka serration, indicate?
Impending ovulation
At what age are mares usually most fertile?
10 years
What is the biggest predictor of fertility in horses?
Age
What is the most effective way of dilating the cervix?
PGF2a
But expensive
What’s going on here?
Persistent hymen (imperforate)
Why can premature intervention with partution lead to urovagina?
Can damage vestibulovaginal junction
What is the concequence of a mare having an inability to evacuate her uterus?
Endometrial cysts
- Caused by dilated lymphatics*
- On US looks like early embryo - careful*
How can endometrial cysts impair pregnancy (2 ways)?
Cysts prevent free movement of embryo around uterus
If very large, the uterus cannot make villi over the cyst and thus the surface area of the uterus is diminished
What are the most commonly found bacteria in free luminal fluid?
Streptococcus zooepidemicus (and other B-hemolytic strep)
- Klebsiella pneumonia*
- Enterobacter cloacae*
Which is more sensitive endometrial cytology or culture?
Cytology
What is used to establish the prognosis and monitor the progress of chronic endometritis?
Endometrial biopsy
What drug is used to treat postbreeding endometritis?
Oxytocin
Frequent tiny doses
What can you give a mare that is prone to postbreeding endometritis to help reduce the inflammatory response to semen?
Single dose of dexamethasone within 60 min of mating
What is a possible concequence of overuse of an intrauterine infusion of antimicrobials to treat chronic endometritis?
Fungal endometritis
VERY persistent
What can be used to disrupt biofilm and improve antimicrobial penetration when treating chronic endometritis? What is the best choice?
Best: N-acetylcystine (ACE)
DMSO
EDTA-TRIS (chelating agents)
Lavage uterus w/LRS, infuse ACE, leave in for 30-90 min, infuse ABx
What capsule types of Klebsiella pneumoniae can grow on the penis of a stallion?
1, 2, 5
7 and 68
What can cause a large ovary in a horse?
Abscess
Hematoma
Tumor (e.g. Granulosa, Theca)
Pregnancy
What type of tumor is this?
Granulosa Cell Tumor
Mare’s may show stallion-like behavior
