When to Neuter your Pet

Most owner are diligent about getting their animal spayed and castrated (ie. neutered). Not everyone understands why and when we should have our animals neutered. For years the typical age for your puppy or kitten was between 5 and 7 months of age. Pet overpopulation has created a push to have animals neutered before they leave the shelter and thus, for the past 15 – 20 years, we have seen a significant shift to earlier and earlier surgery.

Spay / neuter clinics and shelters will now neuter as early as 4 weeks of age with the average being 7-12 weeks of age. We recognize the need to have all of the shelter adoptions neutered ASAP, but for a number of reasons, you may want to consider our recommendations for delaying your pet’s surgery.


  • Overpopulation: this continues to be the primary benefit of neutering. 3-4 million unwanted shelter animals are euthanized each year.
  • Dystocia (difficulty giving birth): this can be costly as it frequently results in c-section or even life threatening if not recognized early enough for medical or surgical intervention.
  • Mammary tumors: the risk of developing mammary tumors increases from 0.5% to 8% if your dog goes through her first heat cycle. Similar results have been found in cats.
  • Pyometra: this is a life threatening infection of the uterus that has been found to be as high as 25% of all unspayed females. This can easily be prevented by spaying at any age.
  • Cancer of ovaries, testes, uterus and prostate.
  • Prostatic disease: non-cancerous problems such as benign prostatic hypertrophy or prostatitis can be prevented or treated by castration.
  • Behavior: reduces aggression (between animals, people or fear based) and avoids roaming behavior.


  • Surgical complications: this can vary from clinic to clinic and surgeon to surgeon but overall reported complication rate is low.
  • Incontinence: has been reported in increased numbers which may be related to the very early age spays. Regardless of age, lack of hormones can lead to incontinence. This is generally easily treated with medication.
  • Cystitis: or recurrent bladder infections. Sometimes this is related to an under-developed urinary tract (males) or external genitalia (females). This is one of the indications we have to allowing your female to have at least one heat cycle.
  • Obesity: this is a problem in American dogs and cats just as in people. Much of this has to do with diet and lifestyle however neutered animals have an increased incidence.
  • Orthopedic problems: we know that in dogs that are neutered prior to closure of their growth plates (around 8 – 12 months) there is an increased incidence of hip dysplasia and more recently what appears to be an increased incidence of cruciate rupture. Male cats neutered before 5 months will have slipped capital physes which is a devastatingly crippling condition of the hip joint that requires surgery to remove the femoral head and neck.

A note on early spays and neuters:

This is where I get to voice my bias. I believe there is enough information to support later aged neutering that I won’t neuter ever prior to 5 months of age and more frequently prefer waiting until 1 year of age. We do still try to spay females prior to her first heat cycle. Talk with your veterinarian regarding the timing of neutering. There are rare occasions (such as recurrent bladder infections secondary to vulvar hooding) where allowing her to have at least one heat cycle may be beneficial.

  • small breed female dogs: 5-8 months
  • small breed male dogs: 8-16 months (depending on behavior)
  • large breed female dogs: 6-8 months
  • large breed male dogs: 12-16 months
  • male and female cats: 5-8 months

What's Next

  • 1

    Call us or schedule an appointment online.

  • 2

    Meet with a doctor for an initial exam.

  • 3

    Put a plan together for your pet.