To Neuter Or Not To Neuter… That Is The Question

by Jennifer Coates, DVM

Apologizes to William Shakespeare, but the decision whether or not to spay or neuter a dog is a big one for owners.  Just like any medical procedure, there are pros and cons, risks and benefits that should be made clear before a final decision is reached.   Unfortunately, veterinarians rarely go over all of these details before surgery, so here is a primer for those who are interested.

The most common argument made for routine spay/neuter is pet overpopulation.  Millions of homeless dogs and cats are euthanized every year in animal shelters throughout North America, and every pet owner needs to take responsibility for this problem.  If your dog produces a litter, you have contributed to pet overpopulation.  Even if you find homes for all the pups, you have very likely taken a home away from a dog waiting to be adopted in a shelter.  You may think that you will be able to stop your un-spayed/neutered dog from roaming and breeding, but the length to which intact males and females in heat will go to reach each other can overwhelm even the best “security system.”

Reducing pet overpopulation is incredibly important, but it does not take into account the well-being of the single individual.  Here are some pros and cons to take into account when deciding what is best for you and your dog:

  • Eliminating messy heat cycles (females)
  • Eliminating the risk of pyometra, a potentially fatal uterine infection (females)
  • Greatly reducing the risk of mammary cancer if a dog is spayed before her first heat cycle (female)
  • Eliminating the risk associated with giving birth (females)
  • Eliminating the possibility of testicular cancer and a reduced incidence of some other types of cancer (males)
  • A much lower risk of some types of prostate disease, e.g. prostatic hyperplasia and infections (males)
  • Reducing aggression and other unwanted behaviors like marking, roaming and mounting (males and females)
  • In many jurisdictions, reduced pet licensing fees (males and females)
  • Reduced “frustration” in an intact individual kept from breeding (males and females)
  • An increased incidence of urinary incontinence (females)
  • A possible decrease in longevity:  A recent study has shown that female Rottweilers neutered after the age of 6 were 4.6 times more likely to reach the age of 13 than were dogs spayed before the age of 6. (females)
  • An increased risk of prostate cancer (males)
  • A change in the appearance of the scrotum, although testicular implants are available (males)
  • An increased incidence of ACL (anterior cruciate ligament) injuries (males and females)
  • Surgical complications (males and females)
  • An increased possibility for weight gain (males and females)
So you can see that the choice is really not as easy as it is sometimes portrayed to be.  In my opinion, however, the standard recommendation that most dogs should be spayed or neutered still holds.  It is the rare pet owner that can dedicate the time and effort needed to prevent unwanted litters, and the tragedy of pet overpopulation is so overwhelming that I see it as the “tie-breaker” in an otherwise difficult decision.


Jennifer Coates, DVM graduated with honors from the Virginia-Maryland Regional College of Veterinary Medicine in 1999.  In the years since, she has practiced veterinary medicine in Virginia, Wyoming, and Colorado.  She is the author of several books about veterinary medicine and animal care, including the Dictionary of Veterinary Terms: Vet-speak Deciphered for the Non-veterinarian. Jennifer also writes short stories that focus on the strength and importance of the human-animal bond and freelance articles relating to a variety of animal care and veterinary topics.  Dr. Coates lives in Fort Collins, Colorado with her husband, daughter, and pets.