Spaying / Neutering

Nearly 70,000 puppies and kittens are born each day in the United States, which is way more than can ever be placed in loving homes. By spaying and neutering our pets, responsible owners do their part to control pet overpopulation and to limit the number of unwanted animals. All dogs and cats adopted through the Pet Adoption Center are spayed or neutered, but your veterinarian can perform this process on other unaltered pets if you choose.


Studies show that surgical sterilization enhances a pet’s health and quality of life. Dogs and cats are shown to:

  • be better behaved.
  • do not “mark” their territory.
  • are less likely to roam the neighborhood.
  • live longer.
  • have less incidences of cancers.

Potential Complications

While spaying and neutering are major surgeries, these commonly performed procedures to remove reproductive organs have low incidence of complications. Using general anesthesia and medications to minimize pain, the surgery usually heals within a few days. Typically, the only complication is that the owner will need to keep their pet calm for a few days until the incision heals.

Fertile Rate

Male dogs and cats are capable of breeding at approximately 6 months of age, and they are likely to being displaying aggressive behaviors when seeking a mate after reaching maturity - unless they are neutered.

Female dogs experience a "heat" cycle every 6 months (depending upon the dog) that can last up to 3 weeks each time. Female cats come into heat every 2 or 3 weeks during the breeding season (typically March through September in our region).

Feral Cats

In addition to adopted pets, the Division of Humane Services provides spay and neuter services for feral and barn cats. Run by volunteers one day each month, the Operation Sterile Feral Program through the Pet Adoption Center has treated thousands of feral cats since its introduction in 2003.

Open to St. Charles County residents only, the cats are vaccinated for rabies, treated for parasites and altered so that they can no longer breed. For more information on the Operation Sterile Feral Program or to make an appointment to participate, please call 314-995-9266. Please leave a message if there is no answer, and your call will be returned soon.