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When to Spay or Neuter Your Puppy: Understanding Your Options
Deciding when to spay or neuter your puppy was once a matter of following your veterinarian’s recommendations. However, these recommendations are evolving as we learn more about sterilization’s impact on lifelong canine health.
In this article, we’ll explore the predominant viewpoints on when to spay or neuter puppies, consider the pros and cons, and provide expert resources to help you make an informed decision for you and your dog.
Early spaying and neutering: Before 6 months of age
Early spaying and neutering are most common in shelter and rescue situations when population control is of the utmost importance. Spaying or neutering a puppy before adoption is convenient for the adoptee and safeguards the puppy and owner from the hassle and potential risk of unwanted litters. Additionally, removing the reproductive organs eliminates the risk for certain cancers including testicular and prostate cancer in males, and ovarian and uterine cancer in females. Spaying a female puppy before their first heat cycle also virtually eliminates the risk for mammary cancer (0.5% risk), the most common tumor type in female dogs.1 Spaying and neutering before sexual maturity may also minimize or prevent sexually driven behaviors such as mounting, urine spraying, and roaming.
While these benefits can seem appealing, pet owners should remember that sex hormones are involved in more than reproduction. These powerful steroid hormones help regulate the pet’s growth and development. Prematurely ending these processes can lead to future health problems, including an increased risk for orthopedic issues such as hip dysplasia and cranial cruciate ligament (CCL) tears, and certain cancer types including osteosarcoma and hemangiosarcoma.2
Traditional age spaying and neutering: 6 to 12 months of age
If you’re like me and you’ve been around the block a time or two, this time frame is likely the most familiar to you. Despite safety improvements in pediatric anesthesia, some veterinarians find this age range more suitable for elective surgery. Waiting until your puppy is 6 to 12 months of age may also allow greater growth and development before surgery, striking a balance between the benefits of early spaying and neutering and the health advantages of allowing sex hormones to circulate for a longer period. However, unless your dog is a small to medium-sized breed or mix, they won’t reach full physical maturity during this time, which may preempt some development-related benefits—including protection from certain orthopedic and neoplastic (i.e., cancer) conditions.3 Additionally small to medium-sized female dogs may undergo their first heat or estrus cycle, which can last between two and four weeks, requires strict management to prevent unwanted pregnancy, and causes mammary cancer risk to rise by 7.5%.1
Adult spay and neuter: After 1 year of age
Opting to delay your puppy’s spay or neuter until they are 12 months of age or older provides additional time for them to reach physical maturity and potentially further minimize certain orthopedic and cancer risks.2 Some studies also suggest possible behavioral benefits, including reduced fearfulness and anxiety compared to dogs spayed or neutered early, but the validity of this, along with most behavior-related findings, remains open for debate.4
However, delaying the procedure also comes with a price. Female dogs who go through multiple heat cycles before being spayed experience a subsequent rise in their risk for mammary cancer (e.g., 26% risk after two estrus cycles). Additionally, the longer your puppy stays intact the more critical it is to supervise their behavior and avoid accidental breeding. This requires dedication and close attention, including tracking your female dog’s cycles and ensuring outdoor spaces are secure to prevent escape or neighboring dogs from entering your yard.
Breed-specific considerations for spaying and neutering
Similar to other health decisions, customized timing for the spay or neuter procedure can provide targeted benefits for many dogs and their owners. While certain breeds such as giant and large breed dogs may benefit from a delayed spay or neuter (e.g., 12 to 18 months or later), small or toy breed dogs may undergo their procedure at a much earlier date with no ill effects. Your veterinarian should take your dog’s breed or breed mix into careful consideration when recommending a timeline for your pet’s procedure.
Another wrinkle: 2024 WSAVA reproductive control guidelines
The World Small Animal Veterinary Association (WSAVA) recently published its first reproductive control guidelines for dogs, taking a somewhat controversial stance on spaying and neutering. Instead of making a firm recommendation on when to spay or neuter, the new guidelines suggest leaving dogs intact, “particularly in breeds prone to health detriments associated with [spaying and neutering],” but cautions owners to be “vigilant regarding mismating risks and ensure regular mammary exams to monitor for the increased risk of mammary tumors.”5
The guidelines stress the importance of case-by-case decision-making and that owners and their veterinarians should carefully weigh the pros and cons to determine whether spaying or neutering is necessary. Such considerations include:
- Individual risks and benefits — The breed, age, and health status of your puppy or dog should always be considered first, along with any known risks.
- Lifestyle considerations — Dogs destined for breeding or showing must remain intact. Alternatively, many dog-friendly services such as doggy day care and other recreational activities may prohibit unaltered dogs. Finally, consider your dog’s exposure to other intact pets to determine the risk and benefit of prolonging spay or neutering.
- Alternative procedures — WSAVA recommends considering other procedures such as a gonad-sparing surgery(i.e., a hysterectomy for females and a vasectomy for dogs) to simultaneously prevent unwanted breedings and maintain the protective benefit of the dog’s sex hormones.
For the most comprehensive and up-to-date information, refer to the WSAVA guidelines summary.
Deciding when to spay or neuter your puppy isn’t as simple as we once believed. Instead, it has a far-reaching impact on their lifelong health and longevity and must be made with care and consideration. Work with your veterinarian to review the advantages and disadvantages of when and how to spay or neuter your dog. No matter which choice you make, remember that your dog’s health is an ongoing investment that requires your time, effort, and care.
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