The Spay/Neuter Decision

Nancy McDonald, BSN, RN, retired


When and how often to vaccinate has evolved over the years and so has  when and what procedure to use for sterilizing dogs. Society moved from agrarian lifestyle to the city in the first of the 20th century.  Then post World War II families moved into housing neighborhoods with enough money to support dogs and cats within the family. Reproduction  of domestic dogs and cats boomed and the city government was asked to assist. As more and more homeless animals were being euthanized, the move to decrease that number was solved by desexing the animals.  Yep! Problem solved. At first anesthesia posed a problem for young animals, but as safer products were developed, animals were being desexed at a younger age. Veterinarians recognized the benefit to reducing the number of unwanted pets and were soon recommending the procedure as early as possible.  As spay/neutering became a standard procedure, veterinarians, pet owners and breeders began noticing trends in sterilized vs intact animals. With technologies improving statistical analysis and an increased ability to communicate, veterinarians, pet owners and breeders began to track the problems and benefits of desexing animals and the relationship of age when sterilization was performed.


Removing ovaries or testes in a dog before adulthood affects all organs.  Removing ovaries or testes after adulthood affects some, good and maybe not so good.  Depending on what website one chooses to read, the list can go on and on. Have all the claims been tested with a solid, valid study?  No, many claims have not. Yet, some detriments as well as some benefits are so common, they are accepted. There are medical options and surgical options to prevent reproduction or to sterilize an animal.  There are situations where nothing should be done. One size does not fit all and what is best may be influenced from three views, rescue workers, pet owners and breeders of purebred dogs.


Benefits and Detriments


A spayed bitch may become incontinent.  A bitch spayed before her first estrous cycle may have chronic vaginitis.  A spayed bitch will not have pyometra.  With each estrous cycle, the risk of mammary cancer in a bitch is increased.  A neutered dog has an increased risk of prostate cancer but a decreased risk of prostatitis.  Spaying or neutering immature dogs effects bone growth plates; a sterilized dog grows taller. A s/n dog gains weight and may become obese.  Spayed or neutered dogs have an increased risk of cancers, transitional cell cancer, osteosarcoma, hemangiosarcoma, but the risk varies greatly in different breeds.  Some believe spayed bitches are more aggressive; early s/n causes decrease in dominance; working/performance dogs work better if intact. Secondary characteristics changes may not be acceptable to some.  




What options are available to prevent reproduction in the female dog?  

  1. For a female ovariohysterectomy, the removal of the uterus and ovaries, is the most common.  It can be done with an abdominal incision or laparoscopically.
  2. An ovariectomy, just removing the ovaries, for a young or middle aged bitch that has not had several littler or has no uterine pathology such as cysts, pyometra, or funny cycles, is available.  It is done often in Europe and the procedure is growing in number in the US. A bitch having ovariectomy will not develop pyometra as it is necessary to have some ovary for that disease to develop.  
  3. There is an ovary sparing surgery that removes the uterus only although it is not recommended.  The surgery requires a big incision and is a difficult procedure. The bitch will still cycle, will stand to breed and if any stump at all is left, may develop pyometra.  
  4. GnRH, an implant that slowly delivers drugs that shuts off hormones that activate cycles is a non-surgical option.  It lasts six months to a year. The problem is when it stops working is unknown.
  5. Available in Europe is a “morning after” pill to give following an accidental breeding but it is not available in the US.


What options are available for the male dog

  1. For male dogs the traditional scrotal castration is most common.  
  2. A vasectomy, removal of a portion of the tubular tract from the testes out thru the penis, can be performed on a dog.  A percentage of reanastomosis can occur allowing the dog to become fertile again. Also, at the end of the site a sperm granulation can form where there is a sperm leak that would require a second surgery.  
  3. A male dog can use the GnRH that shuts down hormones for sperm production.  
  4. Zeuterin is a zinc containing drug that can be injected into the testes obliterating the testicular tissues.


Breeder, Pet Owner, Rescue Worker


Breeders of purebred dogs relish the opinion that the well being of dogs is of utmost concern.  Pedigree research, health tests, training, conditioning all go into showing before breeding for the perfect-as-possible outcome.  Physical and emotional labor is spent on rearing pups. And all has its financial burden. When the time comes to place the “pet quality” pups, breeders usually have contracts to protect the physical, emotional and financial value invested in the litter.  In most contracts are statements to have the pup spayed/neutered (desexed) before the female has her first estrous cycle or the male reaches six months. Some breeders withhold AKC papers until that is accomplished. However, with the knowledge that spay/neutering of a young animal can negatively affect its health, a breeder must make some decisions.


The potential owner who purchases an expensive purebred from a reputable breeder is the recipient of that decision.  Does he/she expect the puppy to grow up to look very similar to the parents or will secondary characteristics changes be OK?  Most pet owners want a puppy to raise, a dog kids grow up with, snuggles with on the couch, takes walks or maybe camping trips with the family.  Many pet owners do not know about nor know how to deal with the bloody problems with an estrous cycle or the wanderlust and deviousness of of a male dog.  The conscientious breeder must decide if the potential owner in knowledgeable enough and disciplined enough to protect that young dog from an accidental breeding.  


Many of those involved in rescue, especially those working or helping in shelters or city pounds, would never consider an intact animal leaving the facility in tact no matter what.  These animals are there because they are throw away animals. Any chance they have to be adopted and live is wonderful, but they should never contribute to the volume of unwanted dogs with an accidental breeding.  Any chance to be adopted and live rather than be euthanized is wonderful. Sterilization at any age is better than euthanasia.


So what should a breeder do?  The middle of the road opinion is wait to sterilize a male until it is three to five years of age.  A female after her first heat. When to have a dog you are placing sterilized will have to be done on an individual basis.


Dr. Andrea Hesser, Canine Breeder Symposium 2015, UC Davis


Margaret Root 2007, “Determining the Optimal Age for Gonadotrophy