Spay or Neuter Your Pet

Sadly, each year in the US more than 15 million dogs and cats are euthanized because of overpopulation.

Altering pets through spay/neuter surgery helps prevent the unwanted birth of animals that may be difficult to place into good homes.

The spaying and neutering of pets can also reduce the incidence of sex-hormone related diseases.

Roughly one-fourth of all dogs in shelters are purebred. Pet owners who are considering not altering their purebred pet are encourage to consider this fact.

Will my dog or cat be a "better" pet after altering?

Yes. In addition to the benefits of not having heat periods and unwanted offspring, the animal's tendency to roam is decreased. Most pets become less aggressive toward people and other animals. Spaying or neutering your pet will not alter the pet's training or its ability to work or hunt.

What are some of the other known advantages of having my pet altered?

  • The neutered male cat has a decreased urine odor and is far less inclined to mark its territory by spraying urine.
  • The neutered male dog is less likely mark territory and display aggression toward other dogs. Neutered dogs have fewer tumors around the anus and decreased urine odor.
  • The spayed female cat and dog do not have reproductive tract disease problems, have less urinary tract infections, and significantly fewer cases of mammary cancer. Spaying prevents the occurrence of pyometra in females. Pyometra is a bacterial infection in the uterus. If the bacteria gets into the pet's bloodstream, it can be fatal.
  • Altered pets are less likely to make inappropriate sexual approaches toward people or objects.
  • They are less likely to roam and are less likely to be aggressive. This helps to prevent pets from becoming lost or stolen, being hit by cars, or contracting a contagious disease through fighting with other animals.
  • Altering your pet helps to control pet overpopulation by reducing the number of litters of puppies or kittens who will need good homes.

What is actually done in a spay or neuter procedure?

In both cases, the animal is given general anesthesia so that it cannot feel any pain or discomfort.

Spay Surgery

A spay surgery (also called an ovariohysterectomy) is performed on females. While performed routinely, an ovariohysterectomy is a major surgery in which the reproductive tract – including the ovaries, fallopian tubes, and uterus – is removed. Bloodwork may be performed to make sure the pet is healthy enough for anesthesia and surgery.


Neutering refers to the castration of a male animal. It is a surgical procedure in which both testicles are removed. Neutering requires considerably less time and equipment than a spay surgery.

How old should my pet be before surgery?

  • Consult with your veterinarian about the best age for your pet to have this surgery.
  • In most cases, it is considered safe to alter dogs and cats as early as eight weeks of age.
  • There may be health risks/concerns specific to certain breeds and sizes of dogs, specifically larger breeds; your veterinarian may advise waiting to perform this surgery until the dog is 6 months to one year or older.
  • As long as they are healthy enough for surgery, there is generally no upper age limit for pets to be spayed or neutered and, in fact, older pets can benefit from the surgery.

Should the female have a heat period or a litter before being spayed?

  • If your pet is going to be a companion animal rather than a breeding animal, then there are no benefits to allowing her to have a litter or to go through a heat period.
  • It is actually healthier for your dog or cat never to experience a heat as it lessens the animal’s chance of getting mammary cancer and decreases the animal’s stress and risks due to pregnancy and delivery.
  • Research indicates that dogs spayed prior to their first heat have less than a half of one percent chance of experiencing mammary cancer as compared to an eight percent chance after the second heat.
  • Cats spayed after their first heat have a seven times greater chance of suffering from mammary cancer than cats spayed prior to their first heat.

Is it safe for a dog or cat to be spayed when she is in heat or pregnant?

Females in good health can have the surgery done when they are in heat or pregnant. Talk with your veterinarian as to what is best for your pet.

Isn’t it unnatural to deprive my pet of a sex life?

No. Dogs and cats have sex strictly to satisfy hormone-induced instincts, not for pleasure.

Why shouldn’t I just keep my female dog or cat confined while she is in heat?

You can do this, of course. But, remember, your unspayed dog will come into heat twice a year for its entire life. A cat comes into heat once a month for its entire life. Also, do not forget all of the other health benefits of spay surgery as listed above.

Will spaying or neutering my pet cause it to become fat and inactive?

No. Weight gain is due to being fed more calories than the animal uses. Be aware of the quantity of food give your pet, and follow feeding instructions as given by your veterinarian or on pet food labels. Older pets need fewer calories than younger ones because they tend to be less active and are no longer growing. Regular play and exercise, along with a proper diet, are the keys to keeping your pet in shape.

I can't afford to spay or neuter my pet. Is there a source for financial assistance?

As part of their commitment to the health of animals and our communities, many veterinarians participate in reduced-cost or subsidized cost spay/neuter clinics or accept spay/neuter coupons from local humane organizations, so contacting your veterinarian is a good first step.

Care Credit is a payment program that, in some cases, offers no interest payment plans for veterinary services. Check to see if your veterinarian accepts Care Credit or call (800) 839-9078.

Other resources


Portland area

  • Animal Aid Portland offers Tom and Mom specials to economically stressed Portland-area residents.
  • The Spay and Save program through the Animal Shelter Alliance of Portland offers discounted surgeries to low-income cat owners receiving government assistance and living in Clark, Clackamas, Multnomah and Washington counties.
  • The Oregon Humane Society offers interest-free loans for spay/neuter procedures through their SNAP program.
  • The Pixie Project provides some spay/neuter and basic veterinary assistance for pets of low-income and homeless residents.

Salem area

Eugene area

  • The Willamette Animal Guild (541-345-3566), is a nonprofit, low cost spay/neuter clinic in Eugene, open Monday through Friday for low-income Lane County residents.

  • The City of Eugene Spay & Neuter Clinic (541-682-3643) operates Tuesday through Friday for qualified low-income residents in the city of Eugene only.

  • Greenhill Humane Society operates a free “feral fix” program on Sundays throughout the year for feral cats, funded with city of Eugene and LCAS support. For information, e-mail

  • Stop Pet Overpopulation Today (541-485-7768, is an all-volunteer nonprofit group that provides vouchers for low-income dog owners in Lane County.

  • Project Spay Ship offers voucher programs for cats and dogs of low-income individuals. Apply online through or and click on financial aid.

  • The LCAS voucher program provides dog and cat spay/neuter vouchers to qualified residents of Eugene. Call (541) 582-3643.

  • The city of Veneta (541-935-2191) offers vouchers for qualified Veneta residents. The vouchers have no income requirement to treat feral cats.

  • The Stray Cat Alliance contributes toward cat spay/neuters at the WAG clinic. Call (541) 554-8657 or e-mail

Douglas County

  • Douglas County Low-Cost Veterinary Services provides spay/neuter services to low income residents of Douglas County. Call (541) 672-3161.

Updated: 2013-02-27 08:00:00

Author: Oregon Veterinary Medical Association