Surgical contraception Flashcards
In what species is female surgical neutering commonly done?
Bitch, queen, rabbit +- rodents & guinea pigs
What are the three main types of surgical contraception in females?
Ovariohysterectomy – Removal of ovaries & uterus
Ovariectomy – Removal of ovaries
Hysterectomy – Removal of uterus
What are the advantages of female surgical neutering?
Eliminates oestrus behaviour (except in hysterectomy)
Prevents pregnancy
Reduces risk of mammary neoplasia, ovarian & uterine diseases
Prevents pseudopregnancy
What are the possible risks of female neutering?
Increased risk of some neoplasias (osteosarcoma, hemangiosarcoma)
Urinary incontinence (more common in certain breeds)
Weight gain due to hormonal changes
Coat texture changes & possible behavioural shifts
Under what conditions can the uterus develop disease after an ovariectomy?
If uterus was already abnormal (e.g. cystic endometrial hyperplasia)
If ovarian remnant is left, leading to continued hormone production
If exogenous reproductive steroids (e.g. oestrogens for urinary incontinence) are given
If there is hormone-producing neoplasm (e.g. adrenal tumour, rare)
What are the advantages and disadvantages of pre-pubertal neutering?
Advantages:
- Prevents first oestrus & mating
- No risk of pseudopregnancy
- Easier, faster surgery with quicker recovery
- May reduce urinary incontinence risk
Disadvantages:
- Smaller animals → Higher risk of anaesthetic overdose
- Delayed growth plate closure → Increased risk of fractures.
- May lead to underdeveloped sexual organs
- Possible higher risk of obesity
(There is current move away from pre-pubertal neuter because early age neuter increases risks esp of some neoplasias & joint diseases)
When is the best time to spay a bitch?
Most common: At least 12 weeks after first oestrus (anoestrus period)
- Spaying before 12w can lead to pseudopregnancy
Avoid neutering during oestrus (increased vascularity)
Spaying too early may increase long-term disease risks
When is the best time to spay a queen?
Avoid oestrus, as reproductive tract is more vascular & friable
How does timing of neutering affect the risk of pseudopregnancy in the bitch?
Spaying in luteal phase (Day 30-70) causes sharp progesterone drop, increasing prolactin → iatrogenic pseudopregnancy
Spaying in anoestrus avoids this issue
If pseudopregnancy occurs, treat with prolactin inhibitors
What are the different methods of castration used in common species?
Orchiectomy (Castration) – Most species
Vasectomy – Teaser rams
Crushing of spermatic cord – Calves
Ischaemic necrosis of scrotum – Lambs
Injection of irritants into testis – Feral dogs in some countries
What are the main reasons for castration in males across species?
Elimination/reduction of male-like behaviour
Prevention of breeding
Treatment of testicular/scrotal conditions
Treatment of hormone-driven conditions (e.g. prostate disease, anal adenoma in dogs)
What are the three main castration techniques?
Open Castration – Vaginal tunic is opened
Closed Castration – Vaginal tunic is left intact
Modified Castration – Open initially, then closed after securing structures
What are the different castration techniques used in horses?
Open Castration (standing with sedation & local anaesthesia)
Closed Castration (under general anaesthesia, reduces herniation risk)
Modified Castration (combines open & closed methods, often done in theatre)
What are the key pre-operative considerations for equine castration?
Physical exam & palpation of scrotum
Suitability for anaesthesia
Tetanus prophylaxis
Antimicrobial & analgesic administration
How is an open castration preformed in the horse?
- Testis is tensed
- 8-10 cm skin incision in scrotum is made 2-3 cm from median raphe
- Incision carried through skin & muscle
- Vaginal tunic is opened & testes pushed out
- Fascia is stripped away using dry gauze
- Cord is emasculated either as 1 or 2 portions (vascular & vas)
- Absorbable ligature may be applied
- Remnant tunic is emasculated
- Tunic, sub-cutaneous tissue & skin are left open
How is a closed castration preformed in the horse?
- As for ‘open’ technique but vaginal tunic is not opened
- Subcutaneous tissue is pushed back with a dry swab
- Transfixing sutures are placed through tunic anchoring vascular portion & then applied circumferentially around whole cord compressing vas
- Cord is emasculated as whole
- The skin is normally left open
How is a modified open castration preformed in the horse?
- Procedure performed as for ‘open’ castration
- Rather then removing tunic, it is twisted along its long axis, transfixed & then emasculated
- Sub-cutaneous tissue may be sutured closed
- Skin may or may not be closed
What are the advantages and disadvantages of open vs. closed vs modified castration in horses?
What are the main castration techniques used in dogs?
Modified (open then closed) – Commonly performed
Closed technique – Preferred in smaller dogs
Open technique – Skin is closed, unlike in horses where skin is left open
What are current opinions on the timing of castration in dogs?
Recommended after 12 months of age in many breeds (post-puberty)
What techniques are used for feline castration?
Open technique with twisting & traction
Open technique with ligation
Open technique with auto-ligation
Skin left open for drainage
What are the bloodless methods of castration in calves?
Elastration (rubber bands)
- Performed within first 7 days
- Induces ischaemic necrosis
- Care for flies and tetanus
Burdizzo method (cord crushing)
- Pull testes down, push cord to side, apply to one cord to level of raphe, then other cord at different level
What are key considerations for surgical castration in calves over 2 months old?
Must be performed by vet using anaesthesia
Local anaesthesia essential, sedation helpful
Open technique is most common
Consider antibiotics, clean environment, age & size
What methods are used for castrating lambs?
Elastration (first 7 days, induces ischaemic necrosis)
Burdizzo (cord crushing) (first 7 days)
Surgical castration is rarely performed
What are the common methods for castrating piglets?
Surgical castration using open technique
Sharp dissection or torsion & traction
Usually no ligature or emasculation used
What are the main surgical castration techniques in calves and bulls?
Open Technique:
- Lateral incisions into each scrotum using scalpel (careful of saphenous vein) or Newberry knife
- Distal scrotum removal improves drainage
Use of Emasculators:
- Crush & cut spermatic cord, providing haemostasis without ligation
- Reduces post-operative bleeding
Why is a closed or modified castration essential in rodents?
Open inguinal canal → High risk of hernia
Wound protection is essential → Subcuticular sutures & Elizabethan collar used
What are common complications that occur during surgical neutering?
Anaesthesia-related
Bleeding risks:
- Bitch: Ovarian pedicle, cervico-uterine stump, broad ligament
- Stallion: Testicular artery
Organ damage:
- Bitch/Queen: Bladder, colon, ureter
- Ureter inclusion in cervical ligatures during a spay
What is the cause of most bleeds during surgical neutering?
Inadequate exposure or poor ligation techniques
How can bleeding be managed in the bitch during surgical neutering?
Increase exposure
Use suction
Ask for assistance
Use mesenteric dam maneuvers to look at ovarian pedicles
Retract bladder caudally to look at cervical stump
Re-ligate, consider fluid therapy
Always check 3 sites before closing abdomen, much easier to re-ligate now rather after recovery
How can bleeding be managed in the stallion during surgical neutering?
Grasp spermatic cord stump with artery forceps
Re-ligate
How can damage to organs be managed during surgical neutering?
Identify organ damaged
effect a repair
What are the common post-operative complications in the recovery phase?
Anaesthesia-related:
- Hypothermia
- Abnormal heart rate (arrhythmias)
- Difficult recovery
- Hypotension
- Hypoventilation
Bleeding:
- Bitch: Bleeding into abdomen → pale mucous membranes, tachycardia, swollen abdomen, blood seepage
- Stallion: Bleeding from open incision → steady blood drip, anything more is likely to be major vessels (e.g. testicular artery) & requires intervention
What are some common complications during recovery in the stallion and what should you do if these happen?
Herniation of omentum
- Don’t pull out any more material
- Resect protruding tissue
- Pack wound / close skin
- Box rest, antimicrobials
Eventration
- Prevent further damage using sheet to hold viscera & prevent any further protruding
- Refer for surgery
What are common post-surgical complications in the short term?
Wound inflammation (seroma)
Scrotal haematoma (firm swelling)
Wound infection & breakdown
Scrotal dermatitis (caused by licking)
- Dogs lick scrotum if clipped or scrub solution not washed away (so don’t clip)
What should you do if wound inflammation (seroma) occurs post surgery?
Consider exercise regimes to prevent before this occurs (e.g. hand walking stallions)
Ensure swelling is simple fluid (not infection / herniation)
Consider removing the fluid
For stallion walking exercise for 30mins twice daily
What should you do if scrotal haematoma occurs post surgery?
Provide appropriate antimicrobial cover
What should you do if wound infection occurs post surgery?
Provide appropriate antimicrobial cover
Prevent self-trauma
Remove any infected material (e.g. skin sutures)
What should you do if wound breakdown occurs post surgery?
Provide appropriate antimicrobial cover
Remove devitalized tissue, debride
Suture if only healthy tissue remains or consider treating as open wound
What long-term issues may arise after surgical neutering?
Surgical materials left behind (e.g. swabs, sutures).
Fistulas bitch:
- Ovarian pedicle → flank fistula
- Uterine stump → inguinal fistula
Chronic infections stallion:
- Scirrhous cord (chronic cord infection)
Bitch: Pyogranuloma, red/brown vulval discharge
Incomplete removal of gonads
What should you do if a long term issue (e.g. surgical material left behind, fistula, chronic infection, pyogranuloma) arises?
Establish nature of the problem (fistulography, vaginal endoscopy etc)
Re-operate & remove devitalized tissue, surgical instrument, swabs, suture material
Provide appropriate antimicrobial cover
What happens if gonads are incompletely removed?
Bitch/Queen:
- Signs of repeated oestrus (ovarian remnant syndrome)
Dog/Tom/Stallion:
- Persistent male behaviour (e.g. aggression, mounting).
- Cryptorchid animals: Testicular tissue left behind
What do you need to do if there are signs of repeated oestrus post neutering in bitch/queen?
Establish this is oestrus by observing behaviour, vaginal cytology
Establish there is ovarian tissue by hormone testing
What do you need to do if there are signs of persistent male-like behaviour post neutering in dog/tom/stallion?
Establish there is androgenisation by clinical exam (e.g. penile spine in cats, musculature in stallions)
Establish there is testicular tissue by hormone testing
What are the long-term physiological effects of neutering?
Increased risk of:
- Urinary incontinence
- Certain neoplasias
- Joint diseases (hip/elbow dysplasia)
- Growth plate fractures (if neutered early)
Physical Changes:
- Body conformation changes
- Loss of secondary male characteristics (muscle mass, mane)
- Taller growth if neutered early (delayed growth plate closure)
Give 5 reasons why feline neutering is indicated.
Population control
Reduce inherent risks of pregnancy
Limit spread of some infectious diseases
Limit reproductive diseases
Limit unwanted behaviours
At what age do cats become sexually active?
4 months
Calculate the fresh gas flow for a T piece for a cat weighing 1kg. Assume minute volume of the cat is 200ml.
0.5L/min
What is in the Quad?
medetomidine, buprenorphine, midazolam, ketamine
What is the benefit of having midazolam in the ‘Quad’?
Reduces the dose needed of the other anaesthetic agents
What are the advantages of midline approach over flank in cats?
Better exposure
What is the risk of stump pyometras in cats?
Low
Are early neuters more prone to obesity?
No
Are cat’s testicles descended at birth?
Yes
