Getting the Mare Pregnant

Question 1

1. What is the normal duration of oestrus in the mare?

Answer 1

1. 2-7d.

Question 2

History taking.

Answer 2

Is mare seen cycling?
- Frequency?
- Duration?
- By who/when?
- Overt behaviours seen?
- Active now?
What samples have been collected and when?
International travel?
Has the mare been covered before?
- When?
- Successful?
- Twins?
- Live foal?
- Easy foaling?
- Maternal nature?
- No coverings/pregnancy?
- Last pregnancy?

Question 3

1. Establishing “free from disease” at start of breeding season.
2. Routine pre-breeding lab samples.

Answer 3

1. After 1st and <28d before breeding.
   After foaling, delayed to >7d after any antibiotic treatment if indicated.
2. Swabs - PCR and culture.
   – Contagious equine metritis swabs.
   –> Taylorella equigenitalis (CEMO) – notificable!
   –> Pseudomonas.
   –> Klebsiella.
   Serum assays.
   – Equine viral arteritis (EVA) –> notifiable.
   – Equine infectious anaemia (EIA) –> notifiable.
   – Streptococcus equi spp equi Strangles.

Question 4

Clinical signs for all 3 bacterial CEM agents.

Answer 4

Active state.
- Vulval discharge – v mild to profuse.
- Spread by:
– mating.
– teasing.
– AI.
– fomites.
Carrier state.
- No overt signs of infection.
- Bacteria established in clitoris and in clitoral fossa and sinuses – mares.
- Bacteria est. on penis or sheath, may have pyospermia if in sex glands.
- Klebsiella and pseudomonas can also become established in urethra and bladder.

Question 5

Relative risks of contagious equine metritis?

Answer 5

• Natural covering greater risk than AI.
• Multiparous mare and mare w/ pathology greater risk than maiden mare.
• History and intended method required to determine risk.
• Spec. stud requests AND appropriate legislation.
  – HBLB (Horserace Betting Levy Board) guidelines.
  – High risk = mares previously positive/exposed for/to disease. OR those travelling from/stallion from/covered outside of UK/Ireland/France/Germany.
  – HBLB LOW risk = all others.

Question 6

1. What types of natural coverings are there?
2. For all low risk, what pre-breeding swabs will be taken?
3. For all high risk, what pre-breeding swans will be taken?

Answer 6

1. • Live in.
     - Walk in.
2. A clitoral swab, endometrial swab (home/stud) (aerobic only), endometrial swab repeated for subsequent seasons (aerobic only) (natural only).
3. 2 clitoral swabs >7d apart (walk in either home or stud, live in both home and stud), endometrial swab either at home or at stud, repeat endometrial swab for subsequent seasons (walk ins either at home or at stud, live ins at stud).

Question 7

1. What do you submit the samples taken for?
2. From what locations are the swabs taken?

Answer 7

1. Aerobic and microaerophilic culture and PCR at approved lab.
2. Clitoral sinus and clitoral fossa.

Question 8

Actions if positive results for any of the 3 pathogens.

Answer 8

Inform:
- STOP breeding now!
- Notify APHA if Taylorella equigenitalis.
- Follow the codes:
– This determines who can manage outbreak:
–> BEVA approved VS may manage if follow codes.
–> APHA vet must manage if not going to follow the codes.
Identify extent spread and treat:
- Swab in contacts.
- Disinfect.
- Inform all relevant parties.
- Treat.
- Test.
- Foal in isolation, test foals.

Question 9

1. What is EVA?
2. Is it notifiable?
3. Possible reasons for seropositive result?
4. Use of vaccine in pregnant mares.

Answer 9

1. Equine Viral Arteritis.
2. YES.
3. • Previously vaccinated.
     - Historical infection.
     - Active infection.
     *cannot distinguish between these.
4. NO use in pregnant mares (inactivated).

Question 10

1. What is EIA?
   – other name?
2. Notifiable?
3. What does a seropositive result mean?
4. Mode of transmission.

Answer 10

1. Equine infectious anaemia.
   – “Swamp Fever”.
2. Notifiable.
3. Infection.
4. Vector (biting flies), fomite, transplacental routes. Possible but uncommon via semen.

Question 11

Breeding soundness examination.

Answer 11

• Perineal conformation.
• Mammary glands.
• Trans-rectal palpation.
• Transrectal ultrasound.
  If problems in history:
• Hysteroscopy.
• Biopsy.

Question 12

Examination of external genitalia…
What do we want in a normal vulva? – why?

Answer 12

Near vertical - 0-10 degrees. Less than 25% above bony pelvis.
– Less chance of soiling when defaecating.
Vulval seal.
– Less urinary and faecal contamination.
– Free draining urine.

Question 13

Vestibule, vagina and cervix exam.

Answer 13

• Speculum and pen torch.
• Pass speculum between vulval lips, progress to cervix.
• Observe for:
  – Faecal contamination.
  – Urine pooling.
  – Bubbles/foam.
  – Cervical appearance.

Question 14

1. Cervical appearance during oestrus.
2. Cervical appearance during dioestrus.
3. Cervical appearance when pregnant.
4. Appearance of cervixitis.

Answer 14

1. Flaccid, red, oedematous and engorged.
2. Erect position, tight, pale pink, best to check for scars and cervical function at this point.
3. Small, tight, similar to dioestrus.
4. Red and haemorrhagic.

Question 15

1. Transrectal uterine ultrasound views.
2. Key features on trans-rectal uterine ultrasound.

Answer 15

1. Transverse (horns).
   Longitudinal (body).
2. • Normal uterus in oestrus w/ grade 3/4 oedema looks like cut citrus slice.
     - Abnormal free fluid shows up as lots of anechoic areas with some echoic areas.
     – Can occur when washed out, post breeding etc.
     - Pair of cysts / twins appears as 2 small areas of anechoic on scan.

Question 16

What should you find on ultrasound if a mare is cycling this year?

Answer 16

Corpus luteum.

Question 17

1. What can be detected about the ovary w/ ultrasound?
2. W/ palpation?
3. What are ovarian ultrasound and palpation useful for?

Answer 17

1. Internal architecture.
2. Shape, size, position, margination.
3. • Confirmation of normality.
     - Detection of cyclicity (CL present).
     - Estimation of stage of cycle.
     - Prediction of ovulation.
     - Detection of pathology.

Question 18

Breeding soundness exam records.

Answer 18

Important to keep them.
Digital or paper.
Must include:
- Cervix.
- CL.
- Follicles >~25mm and consistency.
- Uterine tone and oedema.
- Cysts.
- Free fluid.

Question 19

Endometrial swabs.

Answer 19

For cytology.
- sterile!
- Detection of:
– inflammation (WBCs).
– Bacteria.
- Useful for:
– Screening for disease.
– Indication of likely pathogen,

Question 20

1. Fresh sperm lifespan outside horse?
2. Chilled sperm lifespan outside horse?
3. Frozen sperm lifespan outside horse?
4. Fresh sperm lifespan in mare?
5. Chilled sperm lifespan in mare?
6. Frozen sperm lifespan in mare?

Answer 20

1. <1hr, or <4hrs if extended.
2. <24hrs.
3. Indefinite.
4. > 48hrs.
5. <48hrs.
6. 4-8hrs.

Question 21

1. Fresh sperm % progressively motile?
2. Chilled sperm % progressively motile?
3. Frozen sperm % progressively motile?
4. Sperm dose of fresh sperm.
5. Sperm dose of chilled sperm?
6. Sperm dose of frozen sperm?

Answer 21

1. > 50%.
2. 50%.
3. > 30-35% (below this not recommended for use).
4. Ejaculate.
5. > 500 x 10^6 PMS.
   1000 x 10^6 @ dispatch.
6. 200-300 x 10^6 PMS @ thaw.

Question 22

1. Expected fertility rate for natural covering?
2. Expected fertility rate for chilled AI?
3. Expected fertility rate for frozen AI?
4. Distance between stallion/mare for natural covering.
5. Distance between stallion/mare for fresh AI?
6. Distance between stallion/mare for chilled AI?
7. Distance between stallion/mare for frozen AI?

Answer 22

1. > 80%.
2. 45-70%.
3. 20-55%.
4. Same site.
5. Same country.
6. Same country (or even continent).
7. Anywhere (or dead stallion).

Question 23

Deep intrauterine insemination (usually frozen semen).

Answer 23

• Lower sperm dose required as deposited when ovulation imminent.
• Less post breeding reaction.
• Increases fertility rate.

Question 24

Trends of reproductive efficiency.

Answer 24

Decreases w/ pregnancy progression.
Decreases from natural covering down to frozen AI.

Question 25

Predicting ovulation early oestrus.

Answer 25

Ovary
- Alternate ovary per cycle.
- Require no active CL to ovulate.
- Follicle grows spherically but not high pressure initially so does not collapse neighbours initially.
- Considered a dominant follicle at 35mm.
- Serial scans every 1-2d from 35mm.
Uterine
- Oedema pattern of oedema increases.
Cervix
- Flattening, softening.

Question 26

Predicting ovulation in mid to late oestrus.

Answer 26

• Follicles ovulate 4-5cm TB mares.
  – Follicle points to ovulation fossa.
  – Follicle tone decreases.
  – Oedematous margin.
  –> hyperechoic flecks.
  –> thicker wall.
• Uterine oedema max 24hrs prior.
  – reducing at ovulation (except foal heat).
• Cervix.
  – soft and flaccid.

Question 27

Confirming ovulation has occurred.

Answer 27

• Hypoechoic follicle collapses and fills w/ blood clot to form corpus haemorrhagicum.
• Density then increases as it becomes a corpus luteum.
• ALWAYS check for 2 CL which come w/ a double ovulation.

Question 28

How can we manipulate the mare’s cycle?

Answer 28

Bring forward transitional oestrus.
- affects HT and GnRH production.
Shorten luteal cycle (short cycling).
- reduces dioestrus period.
- give exogenous PGF2a (mimic uterine production at day 14).
Hasten ovulation.
- mock LH peak earlier.

Question 29

To bring forward spring transition.

Answer 29

TB for early foalings.
Method.
- Artificial lights.
- Plane of nutrition.
- Altrenogest (Regumate).
- Domperidone (not licensed in UK).
- Sulpiride (not licensed in UK).

Question 30

Administration of Regumate to bring forward spring transition.

Answer 30

• Administration followed by withdrawal may cause rebound in FSH, triggering cyclicity.
• Need some ovarian activity to be effective.
  – Follicle size min 20-25mm before treatment.
• Oral altrenogest (Regumate).
  – 10-16d treatment orally.
  – 90% mares show oestrus 5d after withdrawal.
  – 60% mares ovulate 11-14d after withdrawal.
  – Expensive.
  – Care w/ handling –> keep in dark, use gloves and extreme care w/ horse feed bowls as is a FEI controlled substance

Question 31

What other method to bring forward spring transition.

Answer 31

Intravaginal device (not licensed in horses) (PRID).

Question 32

“Short cycling”

Answer 32

• Shorten luteal phase.
  – Synthetic naturally occurring PG.
  –> Dinoprost = Lutalyse.
  –> More side effects.
  – Synthetic PG analogues.
  –> cloprostenol = estrumate.
• Need mature CL to be effective.
  – Mare ovulates 2-7d after injection.

Question 33

Hastening ovulation.

Answer 33

• hcG (Chorulon).
  – Inject 1500 i.u. when follicle >3.5cm ovulation 36 +/- 6hrs.
  – Increase dose increase speed (>4500 i.u. reduce pregnancy).
• GnRH analogues.
  – Buserelin (Busol, Receptal).
  – Deslorelin (Ovuplant).
  –> se when >42mm follicle for fixed time AI (40 +/- 4hrs).

Question 34

Problem mares.

Answer 34

• Abnormal cycling.
  – Erratic oestrus.
  – Anovulatory follicle.
  – Granulosa cell tumour.
  – Non-functional ovaries.
• Failure to conceive.
  – Endometritis.
  –> post mating.
  –> chronic.
  –> infective.
  –> pyometra.
  – Uterine cysts.
  *early embryonic death low in horses.

Question 35

1. Aetiology of post mating endometritis.
2. Treatment of post mating endometritis.

Answer 35

1. • Poor uterine drainage.
     – cervical lesions.
     – dependent uterus.
     – impaired uterine contractility.
     - Direct response to semen
2. Lavage.
   - commonly performed routinely as preventative.
   – sterile saline + ecbolics (oxytocin/PG).
   – 4-6hrs post cover / insemination.
   Uteropexy (high value mares?)

Question 36

1. Agents involved in infectious endometritis?
2. Infectious endometritis treatment?

Answer 36

1. • Commensals.
     - Taylorella/Klebsiella/Pseudomonas.
     - yeast and fungi.
2. Lavage and ecbolics.
   Appropriate local antimicrobials.

Question 37

1. What should be suspected of chronic endometritis?
2. Dx of chronic endometritis.
3. Tx of chronic endometritis.

Answer 37

1. Poor uterine defence mechanisms.
2. • Hx.
     - US.
     - Endometrial biopsy (blind per rectum guide).
     – may be focal or generalised, fiving false -ves.
     – useful to prognosticate too.
3. Dilute povidone iodine lavage.
   Hypertonic saline lavage.

Question 38

Hysteroscopy.

Answer 38

Only if problems.
Assess endometrium.
- cysts/fibrosis/adhesions.
- spec. site biopsy.
Treatment.
- laser ablations.
- topicals to oviduct ostia.
Perform after swabs or else risk contamination, generating false +ves.

Question 39

1. Uterine cysts Dx.
2. Treatment?

Answer 39

1. US and hysteroscopy.
   - Range 1 – many.
   - Usually located near bifurcation.
   - Potential confusion w/ pregnancy.
   - Clinical significance varies.
2. Benign – neglect.
   Laser ablation.
   Deflate and ethanol injection.

Question 40

1. Erratic oestrus when?
2. What is seen?
3. Treatment of erratic oestrus.

Answer 40

1. Beginning of cyclicity in spring or post partum.
2. Persistent CLs – prolonged dioestrus.
3. PG administration – multiple.
   Altrenogest.

Question 41

Anovulatory haemorrhagic follicle.

Answer 41

• Often abnormally large follicle later in breeding season, may be sequential.
• Maintaining spherical shape beyond expected ovulation point.
• Fail to rupture to form a CL.
• May appear similar to granulosa cell tumour.
• Treatment = wait and may eventually develop CL and PG.

Question 42

Causes of small and non-functional ovaries?

Answer 42

PPID.
Chromosomal abnormalities:
- Turners XO.
- Intersex.

Question 43

Prevention of oestrus.

Answer 43

• Oral altrenogest long term.
• GnRH vac.
• Double dose ovuplant.
• Manual disruption early pregnancy.
• Pregnant mares can compete under JC and FEI rules until 120d.