Mare Infertility Flashcards
What constitutes infertility?
Complete infertility / sterility = RARE
→ 90% conception rate in healthy young mares
→ But ~60% establish pregnancy (Day 14)
→ So repeat breeders can be ‘normal’
Fertility Requirements:
Regular oestrus cycles
Reasons for failure to show heat:
o Pregnancy*
o Pre-pubertal
o Seasonally anoestrus
o Body condition
o Foal heat often “silent”
o Lactational anoestrus
o Poor teasing ability
o Chromosomal / endocrine
abnormalities (rare) o GnRH Vaccine
Freedom from concurrent disease
Normal reproductive tract
Sound breeding management
Routine Procedures
- Obtain previous breeding history.
- Assess physical condition, general health.
- Evaluate perineal conformation.
- Examine reproductive tract by palpation per rectum.
- Examine reproductive tract by transrectal ultrasound.
- Obtain culture of clitoral fossa, clitoral sinuses.
- Examine vagina and cervix visually with speculum.
- Perform manual examination of vagina and cervix (while
performing next step). - Obtain culture and cytology of uterine lumen (possibly using low
volume lavage technique). - Obtain endometrial biopsy.
History:
- Age?
- Previous, current, intended use?
- Any pertinent health history?
- Has she ever received hormones (or vaccines) for training or behavioural modification?
- Has she cycled normally in the past?
→ Cycle length?
→ Temperament, regularity, clarity of oestrus? - Has she been bred
→ Natural cover, artificial insemination; fresh, cooled, or frozen semen?
→ Fertile stallion? - Uterine infection?
- Conception problems? >3 attempts in
one season (AI/natural) - Has she ever been pregnant? Outcome?
→ # of foals? Embryonic and foetal loss?
→ Resorption, abortion, still birth, neonatal death? - Has she ever foaled?
→ Any problems during
delivery/dystocia?
→ Any postpartum complications? Lactation issues?
Perineal Conformation
-> pneumovaginum -> poor fertility
Ideal conformation:
→ Firmlytonedvulvalseal
→ Craniocaudal vulval slope < 10° off vertical
→ At least 80% of vulva ventral to the dorsal ischial limit (pelvic brim)
→ No air influx on parting of vulva lips (patent vestibule-vaginal seal)
Pneumovaginum
Marginal confirmation
* Sufficient deviation to compromise vestibulovaginal seal
* Permits entry of contaminated air and possible establishment of vaginitis,
cervicitis and endometritis * Reduced conception rates
* Common in:
→ Large breeds
→ Multiparous mare → Aged mares
Caslick’s procedure / vulvoplasty
Simple
* Can have massive effect on fertility
* Restores vulval seal
* Fails to correct vestibulovaginal seal
* Care at service – release for natural service
* release before foaling and replace after foaling
Urovaginum:
Aetiology
* Cranial displacement of vagina and urethral orifice over the pelvic brim
Presentation
* Constant urine discharge (incontinence?)
Sequelae
* Vaginal speculum examination
→ Urine pooling in cranial vagina
* Cervicitis, vaginitis, urometra * Urine scalding
Treatment
* Symptomatic: usually resolves spontaneously within 2 weeks as tract involutes
* Urethral extension surgery if persists
Persistent hymen
- Common: In maiden mares presented for AI → Typically easy to break down manually
- Uncommon: Complete persistence
→ Accumulation of fluid in cranial reproductive
tract
→ May require sectioning (guarded blade)
Cervical incompetence = Final seal
Fibrosis: older mares
→ Fails to dilate at oestrus:
o Uterine fluid accumulation o Avoid natural service
o Most foal normally
→ Fails to close in dioestrus:
o Persistent endometritis
o Progestagens? Evidence basis
Adhesions: Older multiparous mares: Daily manual breakdown – pyometra!
Lacerations: Surgery
Uterine Pathologies - FBs
Foetal remnants
* Rare
Persistent endometrial cups
* Pregnancy loss post day 30
Intrauterine devices
* Marbles
→ Correction of abhorrent oestrus
behaviour
→ 70% client satisfaction? → Placebo
Uterine Pathology - Cysts
Common
* 25% mares (increased incidence in mares >11yo)
→ Endometrial (small <2cm)
→ Lymphatic (larger)
* Impact on fertility poorly understood
→ Few/sparse <2cm: low impact
→ Larger: high impact
* Restrict embryo motility/failure of maternal recognition of pregnancy
* Confusion with early pregnancy
* Restrict functional placental area
- Diagnosis: Ultrasound/ hysteroscopy
- Treatment: Surgical ablation?
Uterine Pathology - Endometritis
- Breeding induced inflammation = a normal physiological process
→ Resolved within 24-36h in most mares, leaving uterus sterile and non-inflamed in time for the arrival of the embryo at day 5-6 post fertilization - Some mares susceptible to endometritis
→ Delay in uterine clearance and inflammatory
response to microbial infection - Common
- Different clinical presentations:
→ Venereal transmission
→ Persistent Mating Induced Endometritis (PMIE)
→ Chronic infectious endometritis
→ Endometrosis (Chronic degenerative endometritis)
→ Pyometra
Diagnosis
* Trans-rectal ultrasonography
* History (breeding), signalment (age)
* Oestrus cycle length: decreased
(endometritis) or increased
(endometrosis)
* Genital exam
* Microbiology
Microbiology
Clitoral swabs (clean procedure)
→ Routine pre-breeding screen
Uterine (endometrial) swab (sterile procedure) → Easiest if taken during oestrus
→ Most informative during dioestrus
→ Warranted if uterine infection suspected or valuable covering (check stud requirements)
Pathogenic Species:
→ Taylorella equigenitalis (CEM)
→ Klebsiella pneumoniae
→ Pseudomonas aeruginosa
→ Haemolytic E.coli
→ β-haemolytic Streptococci
→ Monilia spp.
→ Some Staphylococci
Endometrial Biopsy
- Useful when fertility problems are anticipated * Previous uterine infections
- Previous traumatic foalings
- Uterine pooling on ultrasound examination
- Aged mares
- Older maiden mares
- Can help predict breeding prognosis
- Can indicate advantageous prebreeding treatments
Endometritis Tx:
- Intra-uterine lavage (repeated ~small volume)
- Intra-uterine antibiotics (broad spectrum/targeted)
- Oxytocin and/or PGF2α (don’t give PG if could be in foal)
- Correct predisposing causes (Caslick?)
- Repeated microbiology
- Breeding prognosis: usually fair if managed correctly
- Manage matings as “high risk”/AI (carefully timed, single breeding)
Persistent mating induced endometritis (PMIE)
- Treatment: Avoid breeding more than once per cycle (aim for single breeding)
- 6 hours post breeding; if >2 cm intra-luminal fluid:
→ 2-3 x sterile saline lavage until clear
→ Oxytocin (20iu, iv or im, 6 & 18 hrs post flush) → Intra uterine broad spectrum antibiotic - Breeding prognosis: fair with good management
Endometrosis
- Older mares +/- prolonged oestrus cycle * Chronic endometrial degeneration
- Endometrial swab and biopsy
- Treatment: Mechanical curettage?
- Breeding prognosis: poor
Pyometra
- Uncommon
- Rarely ill with it
- Diagnosis: Often incidental
→ Possibly vaginal discharge, colic - Hx/Cex: Poor genital confirmation, repeated breeding, untreated PMIE, cervical incompetence
Treatment: - Drain purulent material (can be substantial) and perform intensive, long term, high volume lavage
- Endometrial swab and biopsy to evaluate breeding prognosis
- May require recurrent therapy Breeding prognosis: Grave
Anovulatory haemorrhagic follicles
- Ovulation failure
- Intra-follicular haematoma – large (8-12cm)
- Organise and resolve spontaneously – can luteinise DDx: GTCT (no ovarian cyclicity)
AHF: Normal or prolonged ovarian cycle Contralateral ovary normal
Tx: Usually none, or prostaglandin
Granulosa Thecal Cell Tumour (GTCT)
= Benign steroid producing tumour
Diagnosis:
* Acyclic, nymphomania, stallion-like behaviour * Usually unilateral – can be very large
* Contralateral ovary tiny (Inhibin)
* Ultrasound not sufficient to confirm
* Blood tests:
→ ↑plasma[T]–some
→ ↑plasma[E]–some
→ ↑plasma[inhibin]–most
→ ↑↑↑SerumAnti-mullerianhormone
Treatment:
* Removal of tumour and affected ovary (Ovariectomy) = curative
