Spaying and Neutering Facts: Answers to Frequently Asked Questions

Most cat and dog owners realize that having pets sterilized is the right thing to do, but many have concerns about the potential effects of these surgeries on the personalities of their companion animals.

How Does Spaying or Neutering Affect Behaviour?

According to the University of California School of Veterinary Medicine, spaying or neutering a cat will reduce or eliminate a number of undesirable hormone-related behaviours, including urine spraying and fighting in males, and problems associated with heat cycles in females, such as irritability, yowling to attract mates, and drawing aggressive, noisy males to the area.

Cats and dogs that have been spayed or neutered are less inclined to escape from the house and roam far distances. This significantly reduces the likelihood that they will get lost or be run over by cars; injured in fights with other animals; infected with deadly viruses, bacteria, and parasites; or stolen by pet thieves.

Overall, sterilization surgery reduces the majority of undesirable behaviours in companion animals, so spayed and neutered animals are far less likely to be surrendered to shelters for severe behavioural issues than unaltered pets.

Will Spay-Neuter Surgery Change a Pet’s Personality?

According to the University of California School of Veterinary Medicine, spay-neuter surgeries don’t typically change aspects of personality such as playfulness, vocalization, hunting skills, or desire for activity. However, evidence suggests that some spayed pets become more docile or laid back because hormone-related anxiety and aggression are reduced or eliminated, and many pets become more affectionate after the surgery.

Reduced activity and weight gain, often blamed on sterilization surgeries, is usually caused by feeding high quantities of cheap, low-quality pet food and failing to provide exercise opportunities (owners tend not to play with adult cats as often as kittens). Animals that have plenty of playtime and are fed premium foods in reasonable portions are not likely to become obese.

Pet owners also express concerns that male cats and dogs will feel less masculine or suffer some sort of identity crisis as a result of neutering surgery. This worry arises from the tendency to project human feelings onto animals. Animals don’t have a sexual identity that affects their psychological state or a culture in which gender is relevant, so they don’t experience gender identity trauma as a result of sterilization.

Do Spaying and Neutering Affect the Health of Cats and Dogs?

Spaying and neutering can provide a number of health benefits, including:

    • Reduced risk for breast cancer in females (this disease is fatal for about 50% of dogs and 90% of cats, according to the ASPCA)
    • Prevention of uterine and ovarian cancer, as well as severe uterine infections such as pyometra (a common problem that requires hospitalization, antibiotics, intravenous fluids, and emergency spaying)
    • Prevention of testicular cancer and reduced risk for prostate cancer in males
    • Significantly reduced risk of developing genito-urinary problems
    • Decreased anxiety, aggression, and fighting, which reduces the risk of fight-related injuries and abscesses
    • Reduced compulsion to escape and roam, which lowers the risk of pet theft, infectious diseases such as rabies, and car accidents

Additional benefits include:

    • Reduction or elimination of undesirable behaviours such as urine marking in both genders
    • Reduced shedding in females

Are Spaying and Neutering Dangerous Surgeries?

Although all surgeries present some degree of risk, spaying and neutering are considered routine, low-risk surgeries. The risks to unfixed animals are far more significant, as they have a greater likelihood of suffering from fatal diseases and accidents. Pets that have been spayed or neutered live 30% longer on average because of the health and behavioural benefits provided by surgery.

Pets can usually be dropped off at a clinic in the morning and retrieved later the same day, though in some cases an overnight stay is required. Owners are given instructions for post-surgical care, which usually include restricting activity for a week or less.

Recovery times vary based on an animal’s age. Younger animals usually recover very quickly (kittens and puppies may take only a day or two). Older pets usually take a little longer. Most pets are back to normal within a few days.

Does Neutering Increase the Risk of Obesity?

Many pet owners are concerned that their pets will become lazy and obese after sterilization surgery because their metabolisms are a little slower. However, experts assert that obesity in animals is more likely to result from feeding too much cheap pet food. In particular, cats become overweight and suffer health problems when fed a high-carbohydrate diet (while dogs are omnivores, cats are obligate carnivores, which means they need to eat meat).

Pets that are sterilized at a young age tend to be longer and taller when full-grown, but not necessarily fatter. Some altered pets may have an increased risk of obesity because they don’t roam far away from the house and thus get less exercise, but animals that are walked or played with regularly and fed reasonable portions of a good quality food are unlikely to become obese.

Shouldn’t a Female Have at Least One Litter Before She’s Spayed?

Female animals enjoy better health and longevity if they are spayed before having a single litter, and early spaying has no negative emotional impact on pets.

What Is the Best Age to Have Pets Spayed or Neutered?

Many pets are capable of procreating as early as 5 months of age, so they should ideally be altered while relatively young. Based on recent studies, veterinarians are increasingly endorsing very early spay-neuter surgeries.

Many cat and dog organizations recommend sterilization of healthy pets at 8-16 weeks of age.

How Much Do Spay/Neuter Surgeries Cost?

The cost of having pets sterilized varies widely from one clinic to the next, with organizations such as the ASPCA and various humane associations offering much cheaper prices than private clinics. Prices typically range from $70 to well over $200, not including additional services that may be required. Spaying or neutering dogs is usually more expensive than sterilizing cats.

For more cat articles, see the main Cats page. For more dog articles, see the main Dogs page.


    • ASPCA. (2010). “Top 10 Reasons to Spay or Neuter Your Pet.”
    • Cruden, D., Winn Feline Foundation. (1992). “Early Spay/Neuter in the Cat.” Cat Fanciers’ Association.
    • Day, J.W., DVM. (2007). “Why Spaying and Neutering Is Important for Pet Health.”
    • Plotnick, A., DVM. (2006). “Spaying and Neutering: Facts, Myths, and Misconceptions.”
    • Sacramento SPCA. (2008). “Why You Should Spay or Neuter Your Pet.”
    • Second Time Around Aussie Rescue. (n.d.). “Frequently Asked Questions About Spaying and Neutering.”
    • Tierney, R., Partnership for Animal Welfare. (n.d.). “Spaying and Neutering.”
    • University of California School of Veterinary Medicine. (n.d.). “Spaying or Neutering Your Cat.”

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