18.3.1: Parturition, post-partum events and reproductive surgery

Question 1

Diagnosis?

Answer 1

Ruptured pre-pubic tendon / abdominal wall rupture
* Weight of pregnancy has torn muscle fibres -> ventral herniation

Question 2

Signalment and clinical signs for ruptured pre-pubic tendon / abdominal wall rupture

Answer 2

Signalment
* Occurs mainly in heavy horses, mares often old

Clinical signs
* Characterised by massive ventral swelling and oedema
* Abdominal pain
* Often recumbency
* Mare develops saw horse stance with legs extended: this exaggerated wide-based stance is for stability and due to pain
* Need to differentiate from normal pre-partum oedema which is very common

Question 3

Treatment and prognosis for ruptured pre-pubic tendon / abdominal wall rupture

Answer 3

• Could use belly band in late pregnancy for prevention
• Parturition normally needs to be induced -> live foals may be be produced by assisted delivery after induction
• Prognosis poor because mare cannot generate expulsibe abdominal effort

Question 4

How to induce parturition in the mare?

Answer 4

Oxytocin a common choice if close to term

Options:
* Low dose oxytocin given in repeated IV boluses until parturition - most mares respond in 15-90 mins
* High dose oxytocin given as single dose IM - appears to produce longer parturition cf above
* Slow IV infusion oxytocin - appears to produce longer parturition cf low dose boluses
* Twice the luteolytic dose of prostaglandin - more effective the closer the mare is to term

Oxytocin regimes = method of choice

Question 5

Answer 5

Question 6

Indication for induction of parturition

Answer 6

• Mares with dystocia or premature placental separation in previous deliveries
• Mares with abnormalities e.g. rupture of prepubic tendon
• Mares that are very uncomfortable with marked ventral oedema, running milk, and have an open cervix (some mares with ascending placentitis)

Question 7

Complications of induction

Answer 7

• Most mares will require assistance delivering foals
• Induction is associated with dystocia (due inability of foal to rotate), premature placental separation, foetal hypoxia and death, dysmature / immature foals which have difficulties adapting to extra-uterine life and may die

Question 8

Criteria for induction of parturition

Answer 8

• Adequate gestational length - at least 330 days and ideally not until well past this
• Adequate mammary development and milk/colostrum production
• Suitable softening of the cervix (some vets treat with oestrdiol 24hrs before induction to try to help)

Question 9

True/false: prolonged pregnancy typically results in oversized foals

Answer 9

False
Normal pregnancy 310-370 days. Can be up to 390 days.
* This does not generally result in oversize and dystocia
* If concerned, regularly examine mare - you can estimate size of foal by regular ultrasound and measurement of foal eye size

Question 10

How can you predict parturition in the mare?

Answer 10

• Date of conception
• Estimation of foetal age using ultrasound
• Relaxation of pelvic ligaments
• Waxing up of teats
• Change in mammary secretion: sodium:potassium ratio 4 days before foaling; calcium increased to >10 mmol/l 1-2 days before foaling

Question 11

What is the commonest cause of dystocia in the mare?

Answer 11

• Nearly always abnormalities of disposition (failure of rotation of feet, leg position, head flexed backwards etc.)
• Rarely have issues with foeto-maternal disproportion

Question 12

How to check if the foal is alive when trying to correct a dystocia?

Answer 12

• Check for suck reflex
• Check for anal reflex
• Check for arterial pulse (if foal backwards, can check via anus)

Question 13

True/false: if a mare presents 1 day after foaling with a severe tear, you should stitch the wound immediately.

Answer 13

False
* Wait 3-4 weeks before suturing
* The tissue is very oedematous and ragged, huge amounts of tissue will slough
* If you suture now it will break down
* Instead: lavage wound and cover with vaseline

Question 14

You have a mare with a vagino-rectal fistula after foaling but it is too early to suture. How will you try to reduce faecal contamination of the vagina? What else should you look out for?

Answer 14

• May help to gradually change feed type to promote drier, bulkier faeces (e.g. bring in from pasture and feed hay instead)
• Depending on time of year, may have to watch for flystrike

Question 15

A mare with severe tears and a vagino-rectal fistula post-foaling is at risk for…? How will you mitigate this?

Answer 15

• Metritis
• Laminitis

Treatment
* Provide analgesa e.g. NSAIDs
* Provide systemic antimicrobials e.g. penicillin (IM) and gentamycin (IV), TMPS (PO)

Question 16

Classifications of foaling contusions / lacerations / tears in mares

Answer 16

• First degree laceration = damage to skin and mucous membrane only.
• Second degree = damage to skin, mucous membrane and musculature.
• Third degree = complete perforation of the vaginal wall and rectum producing a single opening to the rectum and vagina.

Question 17

Answer 17

Question 18

Answer 18

Question 19

Answer 19

Question 20

Treatment of post-foaling contusions and lacerations

Answer 20

• Lavage wound
• Topical treatment e.g. vaseline to prevent soreness and self-trauma
• Provide NSAIDs
• Check mare’s tetanus status! Provide TAT if required.

Question 21

Answer 21

Question 22

Possible cause, consequences, treatment of uterine prolapse

Answer 22

• Commonly occurs at assisted parturition with traction, attempts to remove the placenta, excess oxytocin administration
• Can lead to fatal haemorrhage
• Can give epidural to replace uterine and bladder prolapses
• Clean, remove as much placenta as possible carefully, replace and ensure fully everted
• Provide NSAIDs

Question 23

What is the prognosis for rectal prolapse in horses?

Answer 23

Prognosis grave - usually fatal

Question 24

How quickly after parturition should a mare pass the placenta?

Answer 24

Within 3 hrs
Any time over this is considered abnormal

Question 25

What are the possible consequences of RFM?

Answer 25

• Metritis
• Laminitis

Question 26

Treatment of RFM

Answer 26

• Bandage tail
• Clean vulva
• Separate allanto-chorion from uterus at vulva; gather membranes and twist them to generate even torsion
• Gentle insert hand between uterus and allanto-chorion
• If not easily separating OR if a lot of bleeding - STOP
• Can then attempt oxytocin (IV drip, or IM single dose) or try preventative treatments and revisit in 8 hrs
• Can fill the foetal membranes with saline, then tie of

Question 27

Mares with RFM can develop metritis and laminitis. What treatments will you use to prevent this?

Answer 27

• Systemic antibiotics e.g. penicillin (IM) and gentamycin (IV)
• Uterine antibiotics (gentamycin): position between the remaining placenta and the wall of the uterus
• Provide NSAIDs
• Provide calcium

Question 28

You attempt removal of the foetal membranes but they do not come easily. You have administered treatment to prevent metritis and laminitis developing. What will you do tomorrow?

Answer 28

• Administer daily antibiotics and NSAIDs
• Perform daily uterine lavage

Question 29

Answer 29

Significant pus-like discharge
-> metritis associated with RFM

Question 30

You diagnose a mare with post-partum metritis due to RFM. What is your treatment? How long will you continue this treatment?

Answer 30

• This is urgent! Need to treat promptly to prevent pedal bone rotation
• Attempt to separate and remove the placenta
• Removal of uterine fluid by scooping / lavage with 1-2L saline and immediately drainage by siphonage
• Broad spec antibiotics systemically e.g. penicillin IM and gentamycin IV
• Local infusion of antibiotics into uterus (gentamycin)
• NSAIDs
• Vasodilators
• Treatment is required daily until the pus and placental debris have disappeared

Question 31

Answer 31

Hypocalcaemia
* In the early phases, see hyperexcitability, muscle fasciculations, may see diaphragmatic thumps where diaphragm out of synch with respiratory system

Question 32

Clinical signs of hypocalcaemia

Answer 32

• Seen immediately pre or post-partum
• Mild cases: hyperaesthesia and dry faeces
• Followed by inhability to prehend food, even when offered it by hand
• Then diaphragmatic asynchrony (thumps) and muscle fasciculations

Question 33

What is hypocalcaemia often associated with?

Answer 33

• Restricted food intake (or e.g. frozen ground)

Question 34

Treatment of hypocalcaemia

Answer 34

• Calcium borogluconate IV slow to effect whilst continuously monitoring cardiac activity

Question 35

Indications for performing Caslick’s vulvoplasty

Answer 35

• Correction of mild conformational abnormalities which cause pnemovagina
• Sunken anus
• Sloping of the vulval

Question 36

Which procedure is illustrated here? What is the purpose of it?

Answer 36

Pouret’s operation a.k.a. perineal body transection
* Aims to increase the distance between the anus and the vulva
* Indications: correction of severe conformational abnormalities which lead to pneumovagina

Question 37

What should you advise the owner about repair of a third degree perineal laceration?

Answer 37

• Mare cannot be used for that breeding season
• Anus may never function again
• May require more than one attempt at surgical repair

Question 38

What is the purpose of a clitoral sinusectomy?

Answer 38

• To remove the sinus areas to ensure that CEMO cannot be harboured prior to export
• Often required before export to the U.S. as no CEM over there

Question 39

What is the treatment for a granulosa cell tumour?

Answer 39

Unilateral ovariectomy
* Often cyclical activity in contralateral ovary does not recovery until the next season