When to Spay or Neuter a Puppy or Kitten, and How Recovery Goes

Spaying or neutering is one of the biggest decisions in a new pet's first year, and the first question most people ask is when. The answer depends on whether you have a dog or a cat, and on your veterinarian's view of your individual animal.

The ASPCA and the Cornell Feline Health Center at Cornell University's College of Veterinary Medicine cover timing, benefits, myths, and recovery below. Your vet makes the final call.

1. The terms

Spaying refers to females and neutering to males, as the ASPCA uses them. Cornell describes the procedures in cats: spaying removes the ovaries and uterus, and castration removes the testes. General anesthesia is always required, Cornell notes.

2. When: dogs

The ASPCA says the traditional age for neutering dogs is six to nine months, but healthy puppies as young as eight weeks can be neutered. Adult dogs can be neutered too, although the ASPCA says there is a slightly higher risk of post-operative complications in older dogs, overweight dogs, and dogs with health problems.

The ASPCA's closing advice on timing applies to both species: talk to your veterinarian to determine the best time for your pet.

3. When: cats

For cats, the ASPCA says it is generally considered safe to spay or neuter kittens as young as eight weeks, and it advises scheduling the surgery before five months of age to potentially avoid the start of urine spraying and eliminate the chance of pregnancy. It also notes a female cat can be spayed while in heat.

Cornell gives a similar window. It says spaying a female kitten at three to six months, before her breast tissue develops, will virtually eliminate her risk of mammary cancer later in life, and that a female should be spayed before her first heat. It describes castration as preferably done at three to six months as well.

4. The health reasons

For females, from both sources:

• Fewer mammary tumors. The ASPCA says spaying decreases breast tumors, which are malignant in about 50 percent of dogs and 90 percent of cats, and that spaying before the first heat offers the best protection.
• No uterine infections. The ASPCA notes spaying prevents uterine infections. Cornell names pyometra, a potentially fatal collection of pus in the uterus, which is ruled out because the uterus is removed, along with uterine prolapse and a range of infections, cysts, and cancers of the uterus and ovaries.

For males:

• No testicular cancer, and fewer prostate problems, according to both the ASPCA and Cornell.

5. The behavior reasons

• No heat cycles. The ASPCA says female cats in breeding season usually go into heat for four to five days every three weeks, yowling and urinating more often to attract mates.
• Less roaming. An intact male dog will try hard to find a mate, the ASPCA says, and once loose risks traffic injuries and fights.
• Less marking. Unneutered dogs and cats are more likely to spray urine to mark territory, according to the ASPCA. Cornell adds that neutering a male cat eliminates the hormones that drive roaming, aggression toward other cats, and urine spraying indoors and out.

6. Myths the ASPCA addresses

• "Spaying or neutering makes pets fat." The ASPCA says spaying or neutering will not cause weight gain; lack of exercise and overfeeding will. Keep monitoring food and activity.
• "Neutering fixes every behavior problem." Not guaranteed. The ASPCA says neutering reduces testosterone but does not eliminate it, and it will not undo learned or habitual behaviors. Results depend on the individual dog.

7. Before surgery

Follow your clinic's instructions. The ASPCA's general guidance is to avoid giving an adult dog or cat any food after midnight the night before surgery, but notes that puppies and kittens need adequate nutrition, so your veterinarian may advise against withholding food. Cornell says adult cats may drink water but should have no food for at least three to four hours before surgery, because anesthesia can cause nausea and vomiting.

8. Recovery at home

The ASPCA's tips for a safe recovery:

• Provide a quiet place indoors, away from other animals.
• Prevent running and jumping for up to two weeks, or as long as your vet advises. Cornell suggests keeping a spayed cat as quiet as possible for about a week to protect the incision.
• Stop licking at the incision, which can cause infection, with a well-fitted Elizabethan collar.
• No baths for at least ten days.
• Check the incision daily.

Cornell adds a medication warning for cats: never give aspirin, ibuprofen, acetaminophen (Tylenol), or other over-the-counter drugs without your veterinarian's approval, because they can be toxic to cats.

Call your veterinarian if you see redness, swelling, or discharge at the incision, if it opens, or if your pet is lethargic, eating less, vomiting, or has diarrhea, according to the ASPCA. Cornell says that within about two weeks, most cats are back to their usual selves.

9. Cost

The ASPCA points out that the cost of the surgery is far less than the cost of having and caring for a litter.

10. Key takeaways

• The ASPCA says dogs are traditionally neutered at six to nine months, though healthy puppies can be done as young as eight weeks.
• For cats, the ASPCA advises surgery before five months, and Cornell recommends spaying before the first heat, ideally at three to six months.
• Spaying before the first heat gives the best protection against mammary tumors, which are malignant in about half of dogs and 90 percent of cats.
• Spaying and neutering do not by themselves cause weight gain.
• After surgery: rest for up to two weeks, use a cone to stop licking, no baths for ten days, and check the incision daily.