diag methods and cycle manipulation in the mare Flashcards
4 days post covering you are asked to examine a mare because she has an itchy vulva
Describe the lesions you see
What is the possible cause and what are the consequences and actions you should take?
multiple, ulercated and pustular lesions affecting the lip of the vulval and ventral commisure down betwee the hind limbs
D/D - herpes virus (in this case EHV 3), need to wear PPE (risk of transmission to other horses)
What questions regarding the reproductive history do you need to ask about during a repro exam of a mare?
- Current Presentation
- Pregnant
- With a foal at foot
- Barren (in equine terms meaning bred last year but did not get pregnant)
- With a specific problem
Really important questions are:
* Age (increased age, more likey to have disease)
* Previous breeding history
* Not pregnant
* Early pregnancy loss
* Abortion / stillbirth
* If barren
* What was the management last year?
* Who was the Vet last year?
* Number of years barren?
What are the key aspects of the examination fo the perineum in horses?
- Long axis of the vulval should be vertical
- Vulvar labia should be well apposed
- No vulval discharge
- No vulval lesions
- Perineum should be intact
- Anus should not be recessed
- Normal vestibulo-vaginal seal
- Need to part vulval lips to establish this
What bacterial venerial pahtogens are screened for in horses?
- Taylorella equigenitalia (Contagious equine metritis organism [CEMO])
- Klebsiella pneumoniae (Capsule types** 1,2,5**)
- Pseudomonas aeruginosa (specific strains but not possible to type these in routine testing so all are therefore [incorrectly] assumed to be pathogenic and are treated as such)
How do you swab for bacterial venerial pathogens in the mare?
- You need to swab the fossa and sinus (and in some cases the uterus)
- Small micro swab for sinus
- You need Amies transport media
- You need to send to Approved Lab
- Culture needs to commence within 48h
- Swabs can also be submitted for PCR (24h result)
Can you breed a mare with klebsiella?
How about pseudomonas?
- klebsiella - yes - depending upon capsule type, if not capsule type 1,2,5 as these are the pathogenic ones
- Pseudomonas - On occasions you may also breed a mare with a ‘positive’ Pseudomonas when you are sure this is not a venereal pathogen
- Actually this is more common in stallions when you have been unable to eliminate the organism and by test-breeding you have demonstrated it to be non-pathogenic
What action would you take if CEM is isolated inthe followign situations?
In mares prior to covering:
Stallions prior to covering:
Mares and stallions after covering:
- In mares prior to covering
- Isolate and treat infected mares
- Notify owners of mares
- Stallions prior to covering
- Isolate and treat
- Notify owners of mares
- Mares and stallions after covering
- Cease covering
- Check all mares implicated in the outbreak
- Do not cover until 3 negative swabs each at least 2 days apart
What viral veneral pathogen affect mares?
- Equine Viral Arteritis
- Equien herpes virus (EHV 1 and 3
- Equine infectious anaemia (EIA)
How do you test for Equine herpes virus, Equine infectious anaemia and strangles in horse entering a stud?
Vaccination planned for Equine Herpes Virus 1 (planned for month 5, 7 and 9 of pregnancy e.g. Equip EHV 1,4)
Inspection negative for signs of Equine Herpes Virus 3 (Equine coital exanthema)
Serologically negative for Equine infectious anaemia (EIA) for horses returning to UK
N.B. EIA is notifiable in the UK
Quarantine on entry to stud to demonstrate no signs of Strep Equi (Strangles) develop
When are uterine swabs performed in the horse? How are these done? When are uterine swabs taken?
- Undertaken for bacterial venereal pathogen screening
- Undertaken in cases of endometritis
- For endometrial cytology as part of detection of endometritis
- For endometrial bacteriology in cases of endometritis to ensure appropriate antimicrobial selection
- For the detection of other pathogens (yeast / fungi – requires specific culture medium)
- Strict asepsis is required
- Always ensure the mare is not pregnant before breaching the cervix
- Guarded swab technique
- Single swab rolled onto sterile / clean microscope for staining for cytology before placing into charcoal-based (Amies) transport medium to send for culture
- Uterine swabs are often taken during oestrus (this is HBLB guidance): collection in the luteal phase would be more appropriate
What is assessed on repro rectal exam of the mare?
Of cervix, uterus, ovaries
* Confirmation of normality
* Confirmation of cyclicity and stage of cycle
* Confirmation of non-pregnancy
* Evidence of gross pathology
* e.g. Absence of, or large uterus
* e.g. Inactive ovaries, or large ovaries
What does this ultrasound of the uterus demonstrate for this mare?
Wheel / dart-board appearance of normal uterine oedema noted during oestrus
What does this ultrasound of the uterus demonstrate for this mare?
Large volume uterine fluid in case of pyometra
What is the cyclicity of the mare?
Seasonally polyoestrus
Normal breeding May to October
* Early spring: mares have transitional period with follicles that don’t ovulate (ovaries can be very large – 2 large ovaries)
* Late autumn: cyclicity ends with silent or anovulatory heat (some pones cycle throught winter)
But, the required breeding season is mid-Feb to July because registered birthdate is 1st January
Anoestrus is cuased due to the supression by melatonin
What is the differnece in cow and mare overian palpation during the luteal phase?
in the cow the CL is easy to feel inthe mare you can only feel the Corpus hemorrhagicum for 4 days and the you cannot feel the CL as it is too soft, therefore inthe horse need to use ultrasound to identify when the mare is in the luteal phase
a mare that has been barren for more than 2 seasons that was served at a professional stud with appropriate veterinary management, which presents to you with fluid within her uterus . What is your diagnosis and what is the prognosis for her getting pregnant?
- HAS got chronic endometrial disease
- WILL have a poor prognosis for getting pregnant
- WILL have a poor prognosis for taking a foal to term
- If you attempt to manage this mare it WILL cost a lot of money
What additional tests can be done to aid with repro disease diagnosis?
- Endometrial Cytology
- More than 5 neutrophils per MPF is classified as abnormal - can be used to diagnose endometritis
- Endometrial Microbiology
- Endometrial Biopsy
- Uterine Endoscopy
- Karytopye
What is the most common pathogen isolated from Endometrial bacteriology?
What is bacteriology helpful?
most common - Streptococcus zooepidemicus
- Identifying organisms means uterine infusion not systemic treatment (essentially this is uterine contamination)
Why is endometrial biopsy performed?
When can biopsy be performed?
- Endometrial biopsy is also often taken in attempt to establish a prognosis: although you really should know based on your history and clinical examination
- Biopsy can be taken at any time except pregnancy or when fibrosis of the cervix prevents it. Mid-dioestrus is a good time as it minimises misleading histological changes
What are the indications for endometrial biopsy?
- Barren mares
- Repeat breeder mares
- Mares with early embryonic death or abortion
- Anoestrus mares (during breeding season)
- Mares requiring surgery of genital tract
- Pyometra or mucometra
- Fertility evaluation - Pre purchase
How is an endometrial biopsy taken?
- Restrain mare, bandage tail, strict asepsis
- Manually dilate cervix then pass sterile basket-jawed forceps into the uterine lumen
- Position forceps so that cutting jaw faces dorsally: open the jaws push onto endometrium, close the jaws and give a ‘tug’ (may need to be forceful)
- It is virtually impossible to rupture the uterus
- Haemorrhage is rarely significant
- The mare is not aware of the procedure
- Sample put into adequate volume of Bouin’s fluid
What pathological changes will you see on endometrial biopsy with:
Acute inflammation:
Chronic infiltrative inflammation:
Chronic degenerative changes:
- Acute inflammation - Neutrophil and occasionally eosinophil infiltration
- Chronic infiltrative inflammation (repeated bouts of acute inflammation) - Mononuclear cells
- Chronic degenerative changes - Layers of fibrous tissue around dilated glands, May also get dilated lymphatics (ageing)
What are the categories for endometial biopsy samples in the mare>
- Category I
- No pathological changes and mare should have normal fertility
- Estimated foaling rate = 80-90%
- Category IIA
- Mild endometrial changes
- 50 to 70% of these mares will foal
- Category IIB
- Moderate endometrial changes
- Inflammatory changes severe enough to decrease fertility and may be accompanied by fibrosis
- 20 to 50% of these mares will foal
- Category III
- Severe endometrial changes
- Uteri may be incapable of supporting fetal development
- Estimated foaling rate = < 10%
What are the uses for uterine endoscopy?
(First ensure the mare is not pregnant)
(Following strict asepsis placement of flexible endoscope into vagina and through the cervix)
* Direct visualisation and detection of congenital or acquired abnormalities
* Cutting or diathermy may be useful for management of some clinical conditions
What is karyotype used for in repro investigations?
Clinical suspicion of problem eg:
* Clitoral enlargement
* Infantile vulva and vagina
* Small uterus
* Small inactive ovaries
In mare that should have reached puberty and is not within the winter anoestrus period
* Remember mares just out of training may not be cycling
What are the karyotype causes for infertility in the mare?
Normal is 64XX
Spontaneous aneuploidy is an occasional cause of infertility
* One of the common abnormalities is 63XO a condition referred to a Turner’s Syndrome
* Tubulogenital tract normal but small, ovaries very small and inactive
* Surprisingly may show irregular non-cyclical oestrous behaviour
* Other abnormalities include 62XX and XXY
How is cyclicity brought on in the mare and the transition period shorteded?
Providing 16hrs artificial light and additional nutrition from 1st December
* Some clinicians also administer GnRH agonists at this time but efficacy is unproven
Once the mare is within the transitional period (follicles greater than 2.5 cm in diameter) progestogens are administered to suppress the release of LH
* Normally Altrenogest (Regumate) is given in feed for approximately 10 days
* Follicles continue to grow during progestogen treatment
* When follicles reach 4.5 cm progestogen treatment is stopped and there is a surge release of LH which induces ovulation
* Some clinicians also administer GnRH at this time to enhance the LH release
When is the optimum time for mating in the mare?
Mares ovulate a secondary oocyte which is immediately fertilisable but remains viable for only 12 hours after ovulation
* Optimum mating in normal mares is 24 to 48 hours before ovulation
How is ovulation predicted in the mare?
Signs of oestrus
With ultrasound
* Follicle size
* Follicle softening
* Follicle wall thickening
* Follicle haemorrhage
* Follicle pointing
* Reduction in uterine oedema
How is the mare’s cycle manipulated in these following situations?
Seasonal breeding and transitional phase:
Hastening ovulation in mares that are in oestrus:
Inducing return to oestrus in the breeding cycling:
- Seasonal breeding and transitional phase - Light, progesterone (given for period of time then withdrawn), + short actin GnRH to stim. ovulation
- Hastening ovulation in mares that are in oestrus - Short-acting GnRH or hCG (which is LH-like)
- Inducing return to oestrus in the breeding cycling - Prostaglandin (after day 5)
This mare is presented for a breeding soundness examination
What are the key features of the conformation that concern you?
What are the likely consquences?
What actions should you consider?
- What are the key features of the conformation that concern you? - substantial movement of the anus cranially (suncken anus), the vulva has been pulled over the bony pelvis, exposure of the vestible
- What are the likely consquences? - faecal contamination of the vestible, risk of endometritis
- What actions should you consider? - surgical correction
