Surgical Contraception Flashcards
In what species are females surgically neutered
Bitches and Queens
Common in rabbits- esp. as best kept in male/female pair
Sometimes rodents and guinea pigs
less common in ferrets
rarely in mares due to alleged poor behaviour
Unilateral ovariectomy performed in many species in case of ovarian pathology
Why isn’t surgical neutering commonly performed in female ferrets (jill)
risk of hyperadrenocorticism and relative success of using off-license depot GnRH agonist
Advantages/ Disadvantages of Ovarioectomy
Elimination of oestrus behaviour and inconvenience
Prevention of pregnancy
Protection against mammary / ovarian / uterine disease (unless uterus abnormal or exogenous hormones subsequently given)
May increase risk of other diseases (some neoplasia and urinary incontinence)
Advantages/ Disadvantages of hysterectomy
Oestrus behaviour and inconvenience continues
Prevention of pregnancy
Protection of uterine disease
No increase risk of other diseases
In what cases would leaving the uterus in result in uterine disease
the uterus was already abnormal
you leave an ovarian remnant
exogenous reproductive steroids are administered
- Reasons for administration of reproductive steroids would include
-Oestrogens for urinary incontinence
there is a neoplasm producing reproductive steroids (e.g. adrenal - possible but rare)
What is current best practice for female neutering
Post-pubertal (laparoscopic) ovariectomy
What happens when you spay in anoestrus
GOOD GRAPHS ON NOTES
Normal progesterone and prolactin profiles in a non-pregnant dog.
Luteal phase 70d
Spaying after d70 (commonly its left until 3m) but before the onset of the next proestrus is the common time for surgery
What happens when you spay in Luteal Phase (30 days after oestrus) in bitch
Removal of the ovaries after day 30 causes a dramatic decrease in progesterone which stimulates an increase in prolactin and causes an iatrogenic pseudopregnancy.
These cases generally don’t resolve spontaneously and require administration of prolactin inhibitors
What happens if you spay in luteal phase (21 days after oestrus)
Removal of the ovaries before prolactin is ‘turned on’ results in a fall of progesterone but no increase in prolactin and so pseudopregnancy is not induced
When would you perform a vasectomy
Mainly in teaser rams, to detect which ewes are in oestrus
When might you inject irritant to testis to neuter a dog
Feral dogs in some countries
4 indications for surgical neutering in male
Elimination or reduction of male-like behaviour
Prevention of breeding
Treatment of conditions affecting the testes and scrotum
Treatment of conditions stimulated by male hormones (e.g. prostate disease / anal adenomata in dogs)
3 different castration techniques
Open
Closed
Modified (opened then subsequently closed
*Refers to the parietal vaginal tunic
3 types of anaesthesia used for castration of the horse
May be conducted standing with sedation, twitch and local anaesthesia
Usually open castration
May be conducted under general anaesthesia in the field
Usually closed castration
May be conducted under general anaesthesia in the theatre
Usually modified technique
5 things to think about in pre-operative evaluation of horse for castration
Physical examination
Palpation of scrotum and inguinal canal
Suitability for anaesthesia
Tetanus prophylaxis in stallion (also goat)
Pre-operative antimicrobial preparations
Pre-operative analgesia
Open castration in horse procedure
Testis is tensed
A 8-10 cm skin incision in scrotum is made 2-3 cm from median raphe
Incision carried through skin and muscle
The vaginal tunic is opened and testes pushed out
Fascia is stripped away using a dry gauze
The cord is emasculated either as one portion or two (vascular and vas)
An absorbable ligature may or may not be applied
The remnant tunic is also emasculated
The tunic, sub-cutaneous tissue and skin are left open
Closed castration in horse
As for ‘open’ technique but the vaginal tunic is not opened
The subcutaneous tissue is pushed back with a dry swab
Transfixing sutures are normally placed through the tunic anchoring the vascular portion, and then applied circumferentially around the whole cord compressing the vas
The cord is emasculated as a whole
The skin is normally left open
Modified Castration in Horse
The procedure is performed as for an ‘open’ castration
Rather then removing the tunic, it is twisted along its long axis, transfixed and then emasculated
The sub-cutaneous tissue may or may not be sutured closed
Skin may or may not be closed
Open v closed v modified castration in horse
Open
Rapid, effective observation of vasculature, allows good drainage, may be useful when conditions likely to be contaminated, herniation risk increased
Closed
Rapid, does not allow observation of vasculature but effective haemostasis if surgical field controlled, peritoneal contamination minimised, herniation risk reduced
Modified (open then subsequently closed)
More time consuming, allows good haemostasis and surgical closure but only if surgical conditions are guaranteed clean, herniation risk reduced
Ways to castrate a dog
Surgical technique under general anaesthesia
– usually a single mid-line incision but surgeon preference.
Commonly performed as:
Modified (open then subsequently closed)
Closed – more often in smaller dogs
Open (but skin closed unlike horse where skin left open for drainage)
Best time for male dogs to be castrated
Post-pubertal- after 12 months of age
Why don’t you clip the scrotal hair for castration
any razor burn caused will mean the dog licks at the area
Techniques for tom cat castration
Open following twisting and traction
Open following ligation
Open following auto-ligation
Skin left open
Effect of age of castration is poorly studied but likely to be similar to dog
Ways to castrate calf
Bloodless technique
Elastration in first 7 days
Induces ischaemic necrosis, care for flies and tetanus
Crushing (Burdizzo)
Pull testes down, push cord to side, apply to one cord to level of raphe, then other cord at different level
After what age must calves/bulls be castrated by a veterinary surgeon and how would this be done
2 months
Local anaesthesia essential, sedation helpful
Nearly always by Open Technique
Consider:
Age and size
Time of year
Clean environment
Antibiotics
Exercise
Open Technique by either
Lateral incisions into each scrotum
Scalpel (watch the saphenous vein! and watch your wrist)
Newberry knife
Removal of the distal scrotum
Emasculators used often without ligation
What is a newbury knife
used to make controlled incision in to bull/calf testes for open castration
How are lambs castrated and when
‘Bloodless techniques’
Elastration in first 7 days
Crushing (Burdizzo) in first 7 days
Surgical castration is rarely performed
How are pigs castrated
Surgical castration
Open technique with sharp dissection or torsion and traction
Usually no ligature or emasculation
How are rodents castrated
Closed castration or Modified technique is essential
Rodents have an open inguinal canal and there is a significant risk of hernia
Careful protection of the wound using subcuticular sutures and Elizabethan collar
