As a responsible pet owner, you know your pet must be spayed or neutered to reap a multitude of health and behavior benefits. But, what you may not know, is the best age for the surgery. When considering when your furry pal should be spayed or neutered, no exact date can be calculated. However, your North Waterloo Veterinary Hospital veterinarian can take a variety of factors into account, and determine your pet’s ideal age to ensure your pet receives the most health benefits from their sterilization. Still, the following general guidelines can help you decide the best time to spay or neuter your cat or dog.

Guidelines for the best age to spay or neuter a cat

Many animal shelters and rescue organizations spay and neuter their kittens as early as possible, especially if the shelter is swamped with litters of unwanted kittens. Some shelter veterinarians perform sterilization surgeries on kittens as young as 6 to 8 weeks, to ensure they are not intact and capable of contributing to the pet overpopulation problem when they leave the shelter. However, spays and neuters at this age come with risks, despite the veterinarian’s pediatrics skills. Such young, small kittens can suffer from hypothermia, hypoglycemia, and surgical complications, because their body systems are still developing.

Outside a shelter situation, most veterinarians opt to follow the “Fix Felines by Five” initiative. Spaying or neutering kittens by 5 months of age provides the health benefits of growing with hormones, but greatly reduces risks of behavior and medical problems. In general, female kittens enter their first heat cycle between 5 and 6 months, and spaying them right before this age drastically reduces their mammary cancer chances. In males, neutering at this age can help prevent hormone-driven behavioral issues like urine spraying. Additionally, kittens who are spayed and neutered by 5 months of age bounce back quickly from anesthesia and surgery, and are often awake and playing like nothing happened in only a few hours.

Guidelines for the best age to spay or neuter a dog

Since dogs come in all sorts of sizes and breeds, determining the ideal time for your puppy’s spay or neuter can be tricky. The American Animal Hospital Association (AAHA) has created general guidelines for spaying and neutering dogs based on current knowledge:

  • Toy and small breeds — Toy- and small-breed dogs typically follow the same guidelines as cats, and should be spayed or neutered by 5 or 6 months of age, when they’re mostly done growing, and will enjoy the reduced reproduction-related risks that come with early procedures. In addition, small male dogs neutered young will be less likely to demonstrate hormone-driven problem behaviors, such as mounting, marking, roaming, and fighting.
  • Medium-size breeds — If a puppy’s predicted adult weight is more than 45 pounds, waiting until they are almost full-grown before being spayed or neutered is best, but this can be challenging to determine if the puppy is a mixed-breed. However, if your puppy is purebred, their breed has possibly been studied to weigh the pros and cons of certain ages for sterilization. For example, spaying or neutering a golden retriever before a year of age has been associated with increased risks of one or more joint disorders—two to four times that of intact dogs. The increase was particularly seen with dogs neutered by 6 months of age. Yet, female golden retrievers had an increased risk of developing one or more cancers—lymphoma, mast cell tumor, hemangiosarcoma, and osteosarcoma—than an intact female’s risk with spaying at any age.
  • Large breeds — For dogs predicted to be more than 45 pounds at adulthood, neutering should occur after growth stops, which is usually between 9 and 15 months of age.  A large-breed, female puppy who is projected to reach more than 45 pounds by adulthood should be spayed between 5 and 15 months of age. Your North Waterloo Veterinary Hospital veterinarian will help you find the best age at which to spay your large-breed puppy.

This wide range can be narrowed by weighing the benefits and risks of spaying at certain ages, but more studies across a wider range of breeds are needed to assess the full range of health benefits and detriments of spaying and neutering. 

Are you unsure when your four-legged friend should be spayed or neutered? Make an appointment for your puppy’s first wellness check, and consult our North Waterloo Veterinary Hospital team, to determine the best age for your pup’s procedure.