Lecture 21: Mare BSE and Infertility

What is the order of an equine BSE (8-10)?

- Basic PE

- History (health/repro)

- Conformation Eval

- Palpation per Rectum

- U/S Exam

- Vaginal Speculum

- Manual Vaginal Exam

- Culture, Cytology, Bx

- Endoscopy (extra)

- Special Testing (extra)

Why are equine BSE done?

- consistent infertility (3 cycles)

- pre-purchase exam

- think there is a problem

- O request

- stallion O request

What is the order of the mare BSE after the conformation evaluation?

1. clean rectum of feces

2. complete U/S of repro tract

3. tail wrap/wash perineum

4. vaginoscopy

5. manual vaginal exam

6. uterine culture/cytology

7. uterine biopsy

When do you do a uterine culture/cytology?

- pre-breeding!!!!

- follow up to treatment

How does equine reproductive swabs for cytology/culture compare to canine?

- equine = UTERINE and looks for inflammation/infection

- canine = VAGINAL for stage of cycle

A uterine culture on a mare comes back positive, but there was no inflammation shown on cytology. Does this mare have an infection?

- unlikely

Why do you do uterine biopsy in mares?

- a good prognosis of whether a mare can carry a foal to term

What is a uterine grade I uterine biopsy in mares?

- normal = 80-90% expected foaling rate

What is a uterine grade IIa uterine biopsy in mares?

- mild changes = 50-80% expected foaling rate

What is a uterine grade IIb uterine biopsy in mares?

- moderate changes = 10-50% expected foaling rate

What is a uterine grade III uterine biopsy in mares?

- severe changes =

What hormone do you check if a mare in is diestrus?

- progesterone

What hormone do you check if a mare can maintain pregnancy

- progestins

What hormone do you check if a mare is pregnant?

- estrogen sulfate

What hormone do you check if a mare was pregnant?

- equine chorionic gonadotropin (eCG)

What is a non-cyclic mare?

- mare not bred since found in heat

- either estrus is not detected or not cycling

What are 9 reasons for non-cyclic mares?

- pregnancy

- retained cups

- prolonged diestrus

- gonadal dysgenesis

- season

- granulosa theca cell tumor

- behavioral anestrus

- ovarian shutdown

- silent heat

How is pregnancy a reason for non-cyclic mares?

- always a R/O and cause of prolonged absence of estrus

What are endometrial cups? When are they seen and what do they secrete?

- structures that form in the uterus of pregnant mares during early gestation

- commonly seen from day 40 to 120

- secrete equine chorionic gonadotropin (eCG; used to test if was preg)

What are retained endometrial cups?

- is they persist beyond normal period (100-120 days) leading to failure to return to estrus

- no treatment, often regress

What is prolonged estrus/pseudopregnancy defined as?

- when the CL lifespan longer is than 15 days

What are the causes of prolonged estrus/pseudopregnancy?

- Diastral ovulation (immature CL at time of PGf2a release)

- Early embryonic death after maternal recognition of preg

- Failure of PGF2a due to uterine abnormality (pyo)

Luteal cyst

What is the most common type of gonadal dysgenesis? What does it look like?

63XO genotype

- small body size

- very small, firm, and smooth ovaries

- uterus and cervix are thin and flaccid

(phenotypically female, sterile, dx = genetic testing)

What does a 63XO genotype gonadal dysgenesis look like?

- small body size

- very small, firm, and smooth ovaries

- uterus and cervix are thin and flaccid

What is male pseudohermaphrodite?

- more common

- external like female with penis and testes

- genetically male

What is a female pseudohermaphrodite?

- male or ambiguous

- ovaries

- genetically female

What are reasons an out of season mare might not be cycling?

- transitional mare = prolonged or shortened estrus or uneven diastral periods

- winter anestrus = shorter days

What is the most common ovarian tumor type? What is it like?

granulosa theca cell tumor

- combo of teratoma, dysgerminoma, serous cystadenoma, arrhenoblastoma

- behavioral abnormalities may be linked

How do you diagnose a granulosa theca cell tumor?

- hormone panel --> elevated inhibin + testosterone

- anti-mullerian hormone

- prostaglandin hormone panel to differentiate from ovarian hematoma = should not be increased

What are causes of behavioral anestrus?

- novel environment = no overt signs of estrus

- too familiar with stallion

- not like the stallion

- maiden mares, wet mares, previously on anabolic steroids

How do you diagnose behavioral anestrus?

- palpation/progesterone weekly to determine if cycling

- evaluate testing program and housing

How do you treat behavioral anestrus?

- careful teasing, frequent palpation, PGF2a to synchronize estrus, AI or restraint for breeding

What are causes of Ovarian Shutdown?

- anovulatory follicle, hemorrhagic anovulatory follicle

- reproductive senescence

- nutritional induced (low BCS, negative energy balance (athletic mares))

- cushings disease

What is anovulatory follicle, hemorrhagic anovulatory follicle?

- can cause ovarian shutdown

- like cystic ovarian disease in catle

- measure progesterone as it is often increased

What is reproductive senescence?

- mares have a limited number of oocytes, meaning they will have a decrease in fertility with age

- aged mares (>25 yo) stop cycling

What are causes of mares that have failure to conceive?

- endometritis

- endometriosis

- metritis

- pyometra

- anatomical defect

- oviductal blockage

- oocyte quality

- stallion factors?

What is endometritis?

- inflammation of the inner layer (endometrium) of the uterus

- no purulent material and no CL present

What are causes of endometritis?

- bacterial or fungal infection of the inner surface of the uterus

- uterine therapies causing irritation

- uterine bx

- post-breeding inflammation

How do you diagnose endometritis like

- inflammatory cells evident on cytology and/or biopsy

- ~30% of normal mares may culture pos during estrus

- confined to the endometrium

What is post-mating induced endometritis?

- occurs due to a dirty breeding, reaction to semen, ect

- fluids and inflammatory cells accumulate

- inhospitable environment for day 7 embryo

What is a semen reaction?

- a normal exaggerated inflammatory response to frozen semen

- seminal fluid seems to decrease the inflammatory response and longevity

How do you treat/manage endometritis?

- correct anatomical defects/barriers

- LAVAGE (solution to pollution is dilution)

- augment uterine clearance

- local/systemic abx

- clitoral fossa reservoir

- bring back to estrus

What is metritis?

- infection of all layers of the uterus

- usually post-partum

- may become systemically ill

- large accumulations of fluid

How do you treat/manage metritis?

- be as clean as possible at parturition

- systemic therapy (fluids, abx, NSAIDs, Ca)

- local therapy: lavage and/or oxytocin

- addressed any traumatized tissue

What is a pyometra in a mare?

- if there is purulent material and a CL

- caused by cervical adhesions, dystocia with trauma, decreased endometrial resistance, ect

- no signs of systemic illness in most cases

- poor prognosis for fertility after

What is acute immunologic clearance like toward sperm cells in the uterus?

- neutrophil migration (chemotaxis, migreation, phagocytosis)

- in normal mares disappears by 48 hours post insemination

What is chronic immunologic clearance like toward sperm cells in the uterus?

- activated monocytes, lymphocytes, plasma cells, giant cells, and eosinophils

True or false

immunologic defect is thought to be a major contributor to problems in mares

false

- minor contributor

What are ways of mechanical clearance in a mare?

- cervical dilation

- myometrial activity (important before cervical closure)

- mucociliary clearance

- lymphatic closure (important after cervical closure)

- uterine position

- uterine stretching with parity

- vascular elastosis of uterine blood vessels

A normal mare should be able to eliminate fluid from the uterus within ___________ post-challenge.

- a few hours

A normal mare should be able to eliminate bacterial contamination from the uterus within ______________.

- 36-48 hours

What makes a mare "susceptible"?

- poor uterine defense mechanisms

- delayed uterine clearance (DUC)

- poor uterine position

- unable to eliminate bacteria by 96 hours

- unable to eliminate >50% of radiocolloid by 2 hours

What types of mares are often "susceptible"?

- usually multiparous and/or older mares

- often get post-breeding endometritis

What are causes of mare infertility due to embyonic loss?

- luteal deficiency

- uterine environment

- embryonic death

- abortion

- systemic illness

- oocyte quality

What are potenital causes for luteal insufficiency?

associated with anything that can cause PGF2a release

- endometrial irritation (trauma and endometritis)

- illness (endotoxemia)

- iatrogenic (lutalyse and biopsy)

How do you treat potential luteal insufficiency?

- altrenogest (can still test mares progesterone)

- progesterone

What are the effects of uterine inflammation after day 6 post-ovulation on embryo health?

- release PGF2a

- luteolysis

- may directly impact the embryo

What is early embryonic death?

- death of an embryo that occurs up to ~45 days

What is abortion?

- expulsion of fetus after organogenesis, but prior to time able to survive

- ~ 45-300 days

What is a immature foal?

- signs of prematurity, but greater than 320 days

What is a dysmature foal?

- not appropriately mature for stage of pregnancy, usually more mature than it should be

- often associated with placentitis or amnionitis