Written by Joan Freed, D.V.M., Humane Society of Santa Clara Valley Veterinary Chief of Staff

Spay or neuter ... for your pet's health!

The most obvious reason for spaying or neutering your pet dog or cat is to prevent adding to the pet overpopulation problem. However, there are other real benefits particularly relating to your pet's health.

No pregnancy: no pregnancy complications

photo of catSpaying, or ovariohysterectomy, is the surgical removal of the animal's ovaries and uterus. By preventing pregnancy, spaying permanently eliminates a source of great physical stress for female animals, including complications such as ceasarian section delivery of the puppies or kittens. What's more, spaying female pets eliminates:

  • attendant males in abundance while the female is in "heat"
  • spotting during the heat period
  • false pregnancies (increasingly common with age)
  • mammary tumors (less than 1% incidence in animals spayed before their first heat, versus higher than 50% incidence in intact female dogs over 5 years of age). In cats, most mammary tumors are malignant.
  • uterine infections (increasingly common with age; often life-threatening)
  • tumors of the ovaries or uterus
  • stress, leading to increased susceptibility to disease
  • need for extra food during pregnancy and nursing.

photo of dogIn female dogs, heat periods occur twice a year and last about 3 weeks each time. Female cats may come into heat every 2-3 weeks. During heat both dogs and cats will be more irritable and nervous than usual, and may even become aggressive and damage furniture or attack strangers. Female cats will howl and rub excessively.

Less testosterone: less trouble

photo of dogIn terms of behavior, male dogs will benefit even more than females from being neutered. Neutering, or castration, is the surgical removal of the animal's testicles. An unneutered male can detect a female in heat even miles away. Neutering decreased roaming by 90%. Responding to the overwhelming urge to reproduce, he will often become nervous and irritable, perhaps picking fights with other dogs, or become lethargic, less responsive to his owner, stop eating, or act ill or depressed. Among the problems reduced or eliminated by neutering male pets are:

  • territoriality and aggression, including urinating to mark territory, and fighting to defend it
  • wandering, escaping, and automobile injuries
  • "riding" inappropriate objects
  • prostrate enlargement (occurs in at least 60% of unneutered male dogs 5 years or older)
  • prostate tumors and infections
  • tumors of the testicles, penis, anal area
  • perineal hernia (rupture of the posterior abdominal wall)
  • stress, leading to increased susceptibility to disease
  • need for extra food.

photo of catBy improving your pet's health, spaying or neutering can also increase her or his lifespan. Best of all, altering will allow your pet more opportunities to be a member of the family, an unconditional benefit for everyone!