Surgical Sterilization

Although a traditional age for surgical sterilization is 5-7 months, more than 90% of shelters that responded to the Canadian Federation of Humane Societies shelter statistics survey spay or neuter the animals in their care before adoption in order to help solve the cat overpopulation crisis in Canada. Early-age spay/neuter at or before 5 months of age and pediatric spay/neuter performed between 6 and 16 weeks of age have significant benefits and are endorsed by the Canadian Veterinary Medical Association. Long-term studies have confirmed that pediatric sterilization is not associated with increased risk of disease, narrowed urethral diameter, or significant behaviour problems, and have also documented some benefits, which include:

  • Effective population control.
  • Improved compliance through pre-adoption or presale surgery.
  • Easier surgeries (e.g., less bleeding, improved visualization of organs, shorter surgery times) and shorter recovery times than for older cats.
  • Small incisions that result in less inflammation and pain during healing.
  • Lower postoperative complication rates than for older cats.
  • Avoidance of stress and costs of spaying females in estrus, while pregnant, or with pyometra.
  • Decreased behaviour problems (e.g., roaming, urine spraying, fighting).
  • Reduction in the risk of mammary adenocarcinoma (91% reduction when females are spayed before 6 months of age).

Anesthesia and Surgery Considerations

Pediatric patients have unique perioperative, anesthetic and surgical requirements. Anesthetic agents available today are safe in kittens as young as 6 weeks of age. Various drug protocols are available in the literature for anesthesia and analgesia for pediatric patients. Cats under 2 kg have a higher risk of anesthetic complications due to factors such as hypothermia, hypoglycemia, inaccurate weights, and inaccurate drug doses. The highest risk period is during the first 3 hours of recovery. Reducing stress and anxiety is important for pediatric sterilization and is best accomplished by housing a litter of kittens together pre- and post-operatively and providing a cage with comfortable and warm bedding and a hiding place for individual kittens. Hypothermia can be prevented by reducing contact with cold surfaces, limiting body cavity exposure, providing carefully protected contact with circulating warm water or heated containers (e.g., carefully monitored water bottles, rice bags, or warming discs) perioperatively, and minimizing the volume of pre-surgical disinfectant. Short surgical times and reversal of anesthetic agents at the completion of surgery minimize hypothermia as well. In addition, particular attention to hemostasis is required for all pediatric surgeries.

Hypoglycemia can be avoided or minimized by restricting pre-operative fasting to 2 to 4 hours, avoiding pre-operative excitement, and feeding the kitten immediately upon anesthetic recovery.

The patient should be closely monitored during anesthesia with particular attention to breathing rate and cardiac output.

As anesthesia and surgery do not affect the response to vaccination, kittens can be vaccinated at the same time as an elective surgery, if required; preferably once the patient is in recovery. Suggested ages for surgical sterilization in various situations include:

Kitten from private home: Often re-homed at about 8 weeks old, they should receive primary vaccination series before surgery, schedule surgery following last vaccination at about 16 weeks of age.

Kitten from rescue organization: Often re-homed at about 8 weeks old, schedule surgery following last vaccination at about 16 weeks of age; some organizations ensure that surgery is performed before re-homing. Encouraging rescue organizations and shelters to use the Cat Healthy Adoption Checklist will educate the client on additional vaccinations, parasite treatment, and disease screening tests required in the first year of life and beyond.

Feral kittens: If caught before 7 weeks old, they may be re-homed and treated as rescue kittens; if part of a trap/neuter/return program, surgical sterilization and vaccination may occur as early as 6-7 weeks of age; identification such as ear-tipping is recommended for cats returned back to the colony.


  • Susan Little, DVM, DABVP (Feline Practice) Bytown Cat Hospital, Ottawa, Ontario
  • Diane McKelvey, DVM, DABVP (Feline Practice) Aberdeen Veterinary Hospital, Kamloops, British Columbia
  • Elizabeth O’Brien, DVM, DABVP (Feline Practice) The Cat Clinic, Hamilton, Ontario
  • Elizabeth Ruelle, DVM, DABVP (Feline Practice) Wild Rose Cat Clinic of Calgary, Calgary, Alberta
  • Kelly St. Denis, MSC, DVM, DABVP (Feline Practice)
  • Margie Scherk, DVM, DABVP (Feline Practice) catsINK, Vancouver, British Columbia

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