Indications for induction of parturition in a mare? How do you induce?
* Very few indications-- e.g. prepubic tendon rupture
* Induction protocol:
- Give 10 IU of oxytocin IV
- If water does not break within 40 minutes: vaginal exam
- if straining for 10 minutes without water breaking: incise chorioallantois
- if straining for 10 minutes after water has broken: check for malpressentation/position
How common is dystocia in mares? Why does it occur?
Rare 1.5- 2.5 % of parturitions
* Mares birth canal easily traumatized
* Foals tend to get stuck with their shoulder (hip lock rare)
* Abnormal presentation, position, posture of legs or neck ('wry neck')
(foals are likely to die if not delivered within 60 minutes of chorioallantoic rupture)
Treament for dystocia in a mare?
* Get mare up and walking
* Epidural should be given if manipulation is not quick
* Clenbuterol injection can help relax uterus
What is the foal heat? Is it a good time to breed her?
* Ends with first ovulation post-partum
* Onset usually 6 to 9 days post foaling (5-12 normal)
* Interval shorter later in season
* Higher EED rate if bred in foal heat esp if OV before D10
** trade off between getting mare in foal as early as possible and ensuring successful outcome of pregnancy
Why is an epidural given?
Stops contractions because mare no longer has sensation of the cervix
Anaesthesia during equine castration
Eg for 450 kg yearling colt poorly handled: Sedate with 10-20 mg ACP usu im or iv, give about 550-600mg xylazine iv, either diazepam 10-20 mg or butorphanol 10mg or both, then ketamine about 1500mg iv bolus. This would usually give me enough time for the procedure, but if not would mostly top up with about 3-4 ml ketamine. Second top up would include some xylazine too.
Thio gives quicker response but may be better to use catheter. Triple drip if encounter problems, again use catheter.
Can use 10-20 mg ACP with 5 ml (10 mg/ml) methadone im if needle shy
RFM in a mare treatment? Consequences?
* Can try 10 IU oxytocin 45 minutes
* If no progress within 2 hours, start treatment
1. Broad spectrum AB (e.g. Penicillin/ Gentamycin)
2. Flunixin meglumine (anti-toxic dose 0.25 mg/kg if concerns for renal function)
3 Oxytocin 10 IU
4. IV fluids
- septic metritis happens very fast
- life threatening consequences e.g. laminitis, septicaemia, toxic shock and death
Diagnosis and locating cryptorchid horse
What is the most common approach for cryptorchid castration?
* Inguinal approach
First PD in a mare? Fixation occurs? When is it too late?
Day 14 PD, Fixation occurs D18 (too late)
What is this? Most common cause?
kicked when mating mares
Priapism- persistent and painful erection of the penis
What are the venereal pathogens we worry about in horses? What samples would you take?
* Equine Viral Arteritis
* EHV 3 (coital exanthema)- genital herpesvirus of equines
* Contagious Equine Metritis (CEM) caused by Taylorella equigenitalis
* Pseudomas aeruginosa and Klebsiella pneumoniae can cause uterine infections
Examination parts to Establish Fertility in a Stallion
Mare bred on Oct 10, date of pregnancy exam? What could you mistake for a conceptus? What would make you decide to take her off regumate?
* Oct 24 - pregnancy exam ** check both ovaries
* Could mistake a cyst for a conceptus
* If you see CL, take her off the Regumate
What artery is typically involved with a peripartal haemorrhage? When does it occur? What should you do?
* Usually middle uterine artery, but can be any (if bleeding into broad ligament: haematoma might build up sufficient pressure)
* Pre, intra, or post partum
* Can be fatal quickly
* Do not move the mare-- confine into small space
Post partum exam of a mare... what should be done? When?
* caslicks should be closed 1 to 4 hours post partum
* Check for:
- vaginal/vestibular lacerations (if more than mucosa is involved risk for bacterial infections and adhesions, tx with systemic antibiotics and topical antibiotic cream e.g. for bovine mastitis)
- perineal lacerations (leave III degree for 6-8 weeks)
- cervical lacerations
uterine rupture (rare sequelae of dystocia)
What three things need to occur for the mare to be ready for a new pregnancy?
1. Uterine Involution
2. Shedding bacteria
3. Resuming regular cyclic ovarian activity
Mare maternal recognition of pregnancy?
* Conceptus signals its presence by transversing whole uterus--> prostaglandin inhibitory factor producted (mobility phase until day 16 where the conceptus gets stuck at the base of the uterine horn)
What is the difference between an open, closed, and semi-closed castration in a horse?
Open refers to a technique where the tunic is open and left open at the end of surgery. Standing castration is generally performed using the open technique (generally not as easy to maintain sterility in standing procedures), whereas castration under GA may be performed using closed or semi-open
Shire mare Bella, 12 yo, pieces of membrane hanging from vulva, foul smell, due date May 23rd (presented May 15th), udder full of colostrum, smelled terrible... Clinical exam showed: WNL (within normal limits) dead fetus in ventral neck flexion and bilateral carpal flexion. What would you recommend?
Fetotomy with IV fluids, broad spectrum antibiotics (penicillin, Gentamicin, Polymixin B), Flunixin- meglumine, Sedation (detomidine/ butorphanol), epidural (lignocaine/ xylazine)
What are the three symptom classifications of mare infertility and reasons why they might be in that category?
Why might a mare be anoestrus?
Which antibiotic is used and when with equine castration? When and what analgesia is standard? What vaccination is absolutely required?
Single injection of antibiotic pre-operatively. Phenylbutazone is given IV immediately pre-op and is usually continued per os for 1-4 days
** Ensure tetanus prophylaxis
How long should the gelding be separated from mares after castration? Why?
1 week because the sperm may remain in the ampulla and ductus deferens for many weeks after castration but are only likely to remain motile for 1 week
What are the types of abnormal cycle length? Examples of causes?
Causes of AHF? Diagnosis? Treatment?
Causes, diagnosis and treatment of persistent CL?
Causes of regular cyclicity but infertility?