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What is spay (Ovariohysterectomy, spay, neuter, sterilization)?

Updated: Feb 27, 2022



Spay, also known as Ovariohysterectomy, neuter or sterilization, refers to the surgical removal of both ovaries and uterus from a female pet.

What is the importance of spaying?


Spaying is important because of:-

  1. Prevention of oestrus (heat) in females.

  2. Control of breeding by sterilization (neutering).

  3. Prevention of mammary neoplasia (breast cancer) if performed early before the first heat.

  4. Reduced prevalence of inguinal hernias.

  5. Prevention of diseases of the ovaries:-

    1. Cancer of the ovaries.

    2. Abnormal oestral (heat) cycles e.g. prolonged heat.

  6. Prevention of uterine diseases in non-pregnant (non-gravid) females

    1. Cancer of the uterus.

    2. Infections of the uterus (Pyometra/cystic endometrial hyperplasia (CEH)).

    3. Inflammation of the uterus (Acute metritis).

    4. Hemometrium (uterus filling with blood).

    5. Subinvolution of placental sites.

  7. Prevention of Uterine diseases in pregnant (gravid) females

    1. Prolapse of the uterus.

    2. Torsion of the uterus.

    3. Rupture of the uterus

    4. Foetal death/mummification/maceration/difficult delivery ( Dystocia).

    5. Abortion / stillbirth.

  8. Prevention of Vaginal diseases

    1. Swelling (Hyperplasia) of the vagina

    2. Prolapse of the Vagina.

    3. Vaginal cancer (neoplasia).

  9. Prevention of Systemic disorders

    1. Management of diabetes mellitus.

    2. Management of epilepsy.

    3. Management of Skin mites (demodectic mange).

What are the pros and cons of spay?


A spay is a relatively safe procedure that reduces the incidences of breast cancer in females if done early. However, it encourages obesity and may predispose some neutered females to urinary incontinence.

When is it appropriate to have your pet spayed?


It is important that spay is performed before the first heat (oestrus) which is usually around 6-12 months of age. In mature bitches, however, the procedure is elective and can be performed either two or preferably four months after oestrus (heat) or at a minimum of nine weeks after delivery (postpartum). The procedure can also be done during oestrus (heat), in old females (geriatrics), in obese females, during pregnancy, in females with concurrent diabetes mellitus disease, in animals with a history of bleeding disorders, however, in these instances, there is increased risk. Essentially, any elective surgical procedures should be avoided within three weeks after administration of modified live vaccines.

How is the spay candidate evaluated pre-operatively?


Ideally, a complete cell blood count (haematology), blood biochemistry, urinalysis, Von Willebrand factor measurement and ultrasound investigations should be done prior to picking up any systemic diseases or complications. However, in some instances, a case comes in as an emergency and the procedure is done immediately.

How is the spay candidate prepared?

A dog is under anaesthetic
Dog under anaesthetic

The animal is fasted for 4-8 hours prior to anaesthesia (depending on age and breed) to prevent reflux inflammation of the oesophagus (oesophagitis) and nausea/vomiting during induction and recovery.

Betadine is applied on a surgical swab to clean and disinfect the surgical area
Betadine is applied on a surgical swab to clean and disinfect the surgical area

The surgical area, midline on the belly from the umbilicus (navel) to the pubic area (pubis), is shaved, cleaned and disinfected before the surgery.

Surgical area being cleaned with betadine in a surgical swab
Surgical area being cleaned with betadine in a surgical swab

The incision starts just behind the navel (umbilicus) extending halfway to the pubic area. General anaesthesia is then administered before the surgery is started.

How is the Spay Procedure?


Step 1 - A midline incision is made between the umbilicus and pubis to get access into the abdomen.

An incision is made on the belly of a dog for spay
An incision is made on the belly of a dog for spay

Step 2 - The uterine horn and ovaries are located, the ovarian suspensory ligaments (SL) is ruptured to release the ovaries.

Uterus and ovaries are located and removed from the abdomen
Uterus and ovaries are located and removed from the abdomen

Step 3 - The ovarian arteries and veins on both sides are located and tied using special threads (sutures) and all the ovarian tissues are removed.

Blood vessels of the ovaries and uterus are tied before removed
Blood vessels of the ovaries are tied before removed

Step 4 - The uterine arteries and veins are tied at the level of the cervix.

Blood vessels of the uterus are located and tied before removal

Step 5 - The uterus is severed at the cervix level about 0.5cm above the topmost thread.

The uterus and ovaries are removed after cut out
The uterus and ovaries are removed after cut out
  1. Checking for haemorrhage (bleeding) from the ovarian blood vessels.

  2. Checking the uterine stump for haemorrhage (bleeding) by elevating the bladder.

Step 6 - Closure of the abdomen: the abdomen is closed by stitching all the layers separately.

Surgical wound after closure and stitching
Surgical wound after closure and stitching

How is the aftercare?

  1. Anti-inflammatories (Painkillers): these are administered immediately pre-operatively and continued for 3-4 days after surgery, and can be supplemented with narcotic analgesics as necessary for the first 24 hours.

  2. Antimicrobial therapy: broadspectrum antibiotics are administered for infection prevention purposes. If there is a uterine infection antibiotics are administered according to culture and sensitivity results. Infection risk is increased when anaesthetic time is longer than one hour.

  3. Wound Protection: Elizabethan collar is used if a dog is observed licking the surgical wound.

  4. Special precautions: Exercise is restricted until skin sutures are removed.

What are the potential complications?

  1. Intra-abdominal haemorrhage (bleeding).

  2. Anaesthetic recovery complications.

What are the challenges after the procedure?

  1. Obesity

  2. Immature genitalia if done in a premature candidate.

  3. Inflammation of vulvar (vulvitis)

  4. Immature behaviour when done in a very young female less than 6 months of age

  5. Exacerbation of urinary incontinence due to urethral sphincter mechanism incompetence.

  6. Hypogonadal syndrome: decreased activity, energy conservation, weight gain and altered feeding pattern.

  7. Surgical wound failure: dehiscence/hernias, seroma if the patient keeps biting or licking the surgical area.

  8. Recurrent estrus due to failure to remove all ovarian tissue (usually right side).

  9. Skin sinuses and granulomas can develop due to allergic reactions to suture material in some cases.

  10. Trapped ureter(s) when one/both ureters are included in uterine stitching, causing hydronephrosis or vagino-ureteral fistula with severe incontinence.

  11. Adhesions, occasionally, encircling between the distal colon and uterine stump.

  12. Uterine stump pyometra with retained ovarian tissue, or exogenous progestational compound administration.

What is the Prognosis?


Prognosis is good when performed in healthy animals.



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