18.3.1: Parturition, post-partum events and reproductive surgery Flashcards
For more detail on surgery and surgical techniques, see lecture of same time on 23/1/2023
Diagnosis?
Ruptured pre-pubic tendon / abdominal wall rupture
* Weight of pregnancy has torn muscle fibres -> ventral herniation
Signalment and clinical signs for ruptured pre-pubic tendon / abdominal wall rupture
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
Treatment and prognosis for ruptured pre-pubic tendon / abdominal wall rupture
- 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
How to induce parturition in the mare?
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
Indication for induction of parturition
- 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)
Complications of induction
- 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
Criteria for induction of parturition
- 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)
True/false: prolonged pregnancy typically results in oversized foals
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
How can you predict parturition in the mare?
- 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
What is the commonest cause of dystocia in the mare?
- Nearly always abnormalities of disposition (failure of rotation of feet, leg position, head flexed backwards etc.)
- Rarely have issues with foeto-maternal disproportion
How to check if the foal is alive when trying to correct a dystocia?
- Check for suck reflex
- Check for anal reflex
- Check for arterial pulse (if foal backwards, can check via anus)
True/false: if a mare presents 1 day after foaling with a severe tear, you should stitch the wound immediately.
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
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?
- 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
A mare with severe tears and a vagino-rectal fistula post-foaling is at risk for…? How will you mitigate this?
- Metritis
- Laminitis
Treatment
* Provide analgesa e.g. NSAIDs
* Provide systemic antimicrobials e.g. penicillin (IM) and gentamycin (IV), TMPS (PO)
Classifications of foaling contusions / lacerations / tears in mares
- 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.
Treatment of post-foaling contusions and lacerations
- Lavage wound
- Topical treatment e.g. vaseline to prevent soreness and self-trauma
- Provide NSAIDs
- Check mare’s tetanus status! Provide TAT if required.
Possible cause, consequences, treatment of uterine prolapse
- 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
What is the prognosis for rectal prolapse in horses?
Prognosis grave - usually fatal
How quickly after parturition should a mare pass the placenta?
Within 3 hrs
Any time over this is considered abnormal
What are the possible consequences of RFM?
- Metritis
- Laminitis
Treatment of RFM
- 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
Mares with RFM can develop metritis and laminitis. What treatments will you use to prevent this?
- 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
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?
- Administer daily antibiotics and NSAIDs
- Perform daily uterine lavage
Significant pus-like discharge
-> metritis associated with RFM
You diagnose a mare with post-partum metritis due to RFM. What is your treatment? How long will you continue this treatment?
- 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
Hypocalcaemia
* In the early phases, see hyperexcitability, muscle fasciculations, may see diaphragmatic thumps where diaphragm out of synch with respiratory system
Clinical signs of hypocalcaemia
- 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
What is hypocalcaemia often associated with?
- Restricted food intake (or e.g. frozen ground)
Treatment of hypocalcaemia
- Calcium borogluconate IV slow to effect whilst continuously monitoring cardiac activity
Indications for performing Caslick’s vulvoplasty
- Correction of mild conformational abnormalities which cause pnemovagina
- Sunken anus
- Sloping of the vulval
Which procedure is illustrated here? What is the purpose of it?
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
What should you advise the owner about repair of a third degree perineal laceration?
- Mare cannot be used for that breeding season
- Anus may never function again
- May require more than one attempt at surgical repair
What is the purpose of a clitoral sinusectomy?
- 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
What is the treatment for a granulosa cell tumour?
Unilateral ovariectomy
* Often cyclical activity in contralateral ovary does not recovery until the next season
