Final: Mare cycle and breeding; Non-pregnant mare Flashcards by Sarah Sabler

Descibe the cervix of a receptive mare.

Short and soft

Like a wilted rose

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The dorsal commisure of the vulva should be at the level of the _________.

Ischial arch

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A second degree _____________ is a common, frequently overlooked and serious lesion that is easily corrected.

Perineal laceration

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What part of the anatomy helps create a seal between the vestibulum and the vagina?

Perineal body

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On US evaluation of the repro tract, in which orientation are the uterine body and uterine horns viewed?

UB: Longitudinal

UHs: Cross-section

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What is the ideal month for a foal destined to be racehorse to be born in?

January

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Follicles formed during the transition period are

a. steroidogenically incompetenet
b. enlarged
c. steroidogenically competent and form estradiol
d. hyperfertile

a. steroidogenically incompetenet

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How many waves do most horses have in their estrus cycle?

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How much do follicles grow per day? What hormone reduces the growth rate of follicles?

3mm/day

Progesterone

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At what size do follicles develop ovulatory capacity?

35mm

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Ovulation occurs in response to rising ___ levels that peak ___ days after ovulation.

Two

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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

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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

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Occytes degenerate by ____ hours/days post-ovulation. This is why insemination should occur ____(prior to/ after) oculation.

12-16 hours

Prior to

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When do fertilized embryos enter the uterus?

By 5.5 days after fertilization

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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

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Why can administering hCG cause anaphylaxis?

Can cause production of autoantibodies

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What is Deslorein accetate?

Long-acting injectable GnRH

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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

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What are the side effects of Dinoprost (Lutalyse)?

Sweating

Colic

Depression

Prostaglandin labeled for horses (Cloprostenol/Estrumate is extra-label)

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On what does the interval between PGF2a administration and estrus or ovulation depend?

Follicle size

<25mm = 7-10d*
>25mm = 3-5d*
>35mm= 1-4d*

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What is the most common exogenous P4 product for horses?

Regu-Mate(tm)

(Altrenogest)

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How does a GnRH implant prevent estrus?

Superstimulation of GnRH receptors -> receptors internalize -> cannot be stimulated anymore

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What is the best way to determine whether a mare is receptive?

Teasing with a stallion

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How long does capacitation within the female repro tract take?

6 hours ## Footnote *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 ## Footnote *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 ## Footnote *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?

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 ## Footnote *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 ## Footnote *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) ## Footnote * 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 ## Footnote *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 ## Footnote *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 ## Footnote *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 ## Footnote *Mare's may show stallion-like behavior*