Endometritis and metritis in the mare Flashcards
What happens in a normal mating in the mare?
- Ejaculate enters the uterus
- Contamination with commensal bacteria
- Contractions
- PMNs - polymorphonuclear neutrophils
- Clearance in 24h
- This is a physiological short duration inflammatory response
- Sperm move to the fallopian tubes
What are the consequences of pneumovagina?
- Gas can move into the uterus
- Bacteria that has entered the vagina with the gas can enter the uterus when the cervix is open during the cycle - metitis
- Increased bacterial load within the vagina
- Disturbed microflora
- Possibility of faecal material in vestibule
- Potential for vaginitis / cervicitis
- Reduced fluid drainage from vagina?
If mare becomes pregnant greater risk of ascending placentitis
What could make a mare more susceptible to developing endometritis?
- obstruction to fluid drainage - narrow cervix, endometrial cyst
- poor uterine contraction
- dependant uterus (hangs low, due to previous pregnancies and stretch)
- poor conformation (doesn’t need to be mated)
- high vaginal bacterial load
- Multiple breedings
- Abnormal cervix
these create a ‘susceptible’ mare
What is persistent mating-induced endometritis?
What are the concequences?
- Endometritis develops and persists
- Associated with commensal bacteria (staph, strep zoo)
- If uterus initially ‘clean’ then sperm still reach fallopian tube
- Mare may become pregnant
- But uterine environment is hostile
- Embryo affected when enters uterus (d7)
- Mare will short cycle
What treatments are likely to be useful in cases of PMIE endometritis?
after detecting fluid on ultrasound:
Mare is probably pregnant so need to resolve before the embryo enters the uterus:
* Detect early (common on studs to scan 1 day after breeding)
* Remove the fluid:
* Aspiration
* Lavage (warm saline also increases contractility)
* Promote further drainage:
* Massage and lift uterus
* Ecbolics: Oxytocin or Cloprostenol (before or shortly after ovulation)
* Control bacteria (these are commensals):
* Medium volume antibiotic 20ml into uterus, Daily treatment (until fluid resolves or until when..?) - (penicillin, penicillin/streptomycin)
* Don’t re-breed
What treatments are likely to be useful in future cycles of mares you know are ‘susceptible’ to endometritis?
- AI - (could add antibiotics semen extender to the semen before insemination)
- clean vulva and penis
- put antibioic semen extender into mare uterus before breeding
- examine mare earlier (4h)- eg breed in morning, examin and start PMIE treatment in the afternoon
- Breed early (as gives you more days to treat before embryos enter uterus)
- Improve conformation
Treatment principles
* Remove fluid
* Promote drainage
* Prevent bacterial growth
* Augment uterine response
Pre-emptive – prevent or reduce contamination
What happens if the inflammatory fluid of PMIE isn’t resolved and the mare is not treated?
the PMIE will develop into a chronic
endometritis
* Persistence of the fluid will often have caused endometrial changes
* These degenerative changes can impair the uterine environment and placental development -> pregnancy resorption is more common
* Most commonly mares with CE have fluid within the uterus
* Endometrial cytology and culture confirm inflammatory fluid
* Endometrial biopsy confirms uterine degenerative changes
How is chronic endometris treated?
Treatment principles
* Remove fluid
* Promote drainage
* Prevent bacterial growth
* Augment uterine response
* Don’t breed the mare until the uterus is clean
* Consider pre-emptive treatments mentioned previously
E.g.
* culture to know what bacteria is present
* lavage and aspirate the fluid
* intra-uterine antibiotics (penicillin, penicillin/streptomycin)
* oxytocin - cause uterine contractions
* treat the underlying condition - add condition to mare if sunken anus
What is endometritis?
What is metris?
Endometritis
* Endometrial contamination
* May be endometrial degeneration
* Intial inflammation = PG release = short cycle
Metritis:
* Nearly always post partum in all species
* Endometrial damage allows deeper invasion
* Animal is usually sick (requires systemic treatment)
* In mares a key concern is toxaemia and laminitis
What are the predisposing factors for Metritis in mare?
- Dirty environment
- Dystocia
- Obstetrical intervention
- Retained fetal membranes
- Metabolic
What are the treatment options for metritis?
- Treatments as for endometritis
- Additional systemic ABs (as well as IU)
- NSAIDs
- Fluid therapy
- Nursing Care
- Daily treatment is required until the condition resolves
- This is also going to be the same approach with RFM
- *
What is pyometra in the mare?
How dose it present?
What is the treatment?
- Uncommon in the mare
- Chronic endometritis = repeated short cycles but then ultimately the endometrial changes are severe and the endometrium fails to produce PG
- The** CL persists** as it is not lysed by PG, the mare then changes to having long intervals between cycles (e.g. 40 days)
- When in oestrus there is often a vulval discharge
- Usually significant problem is abnormal cervix - doesn’t open fully
- Often the mare is not unwell (this is a chronic endometritis not a metritis – like condition)
- Treatments include ‘the usual’, but may also include exogenous PG, to bring the mare into oestrus to help with opening the cervix for uterine lavage
Endometris is normally caused by something that has prevented the elimination of commensal organisms or has allowed their overgrowth? what is the other cause of endometritis in the mare?
Venereal Pathogen Endometritis -why we rely on pre-screening inorder to know the endometris is not due to venereal pathogens
