The Spay Neuter Debate – Fact or Fiction

Fiction – Anesthesia and surgery is not safe for puppies and kittens.
Fact – pediatric spay and neuter procedures have been performed since 1990’s and veterinary schools are now teaching these procedures. The medications used are also much safer than in the past and can be used on animals as young as 6 weeks old. Pre-surgical blood work to identify any decrease in your pet’s ability to safely undergo anesthesia. Intravenous fluids are also highly recommended for the safety of your pet while having surgery.

Fiction– Pet overpopulation isn’t a problem.
Fact– The Canadian Federation of Humane Societies reported that in 2015 alone, SPCA’s euthanized over 4,000 dogs and 17,000 cats. Animals euthanized at other establishments (homeless shelters, individual/private shelters, rescue and foster groups, and municipal animal services) are not included in these numbers.

Fiction– female dogs and cats are better pets if they are allowed to have a litter.
Fact– there is no scientific evidence to support this. A well-behaved pet is based on their genetics, training and socialization, not if they have had a litter.

Fiction– There are no risks to leaving my animals intact.
Fact – There are several serious and even life-threating risks to leaving your pet intact:

  • Females – pyometra (infected uterus)- life –threatening emergency that requires surgery to save her life, unplanned pregnancies that lead to unwanted puppies and kittens, development of cancers – ovarian, uterine and mammary, roaming, injuries and unwanted sexual/territorial behaviours
  • Males- testicular and perianal cancer, perineal hernia’s prostatitis, prostatic cysts, unwanted puppies and kittens, roaming, injuries and unwanted sexual/territorial behaviours

Fiction– My pet will get fat after being spayed/neutered.
Fact– Intact animals require more calories than spayed or neutered pets. Calories need to be adjusted downwards after your pet is spayed/neutered to prevent obesity. Feeding the proper amount of calories and regular exercise are key strategies in maintaining your pet’s healthy weight.

Fiction– early spay and neuter will cause my dog to get certain cancers
Fact – This is where the grey area in veterinary medicine comes into play. There are studies that indicate there may be an increased risk for certain breeds of dogs to possibly develop some cancers when spayed/neutered early. Mammary tumours, lymphoma, mast cell tumours, hemangiosarcoma, osteosarcoma and transitional cell carcinoma’s are thought to have a mild increase in risk. This information is predominantly directed at Golden Retrievers, Labrador Retrievers, Vizslas and Rottweilers. The studies were done with pure bred dogs and it is unsure if the results can be extrapolated to other purebreds or mixed breeds.

Fiction-spaying/neutering early will stunt my pets growth
Fact– All bones in the body have ‘growth plates’ – which are just that – sections of the bones that contribute to the length of growing bones. These growth plates all ‘close’ or stop growing based on the presence of sex organ hormones. By spaying/neutering we remove those influences and thus the bones continue to grow = taller animals. This can sometimes impact the conformation of their bones and joints which may lead to certain orthopedic conditions. The two main conditions are hip dysplasia and cranial cruciate ligament injuries. Both of these conditions are also significantly impacted by weight, breed size and age. Large and Giant breeds as well as Golden Retrievers, and Labrador Retrievers seem to be more impacted. Hip dysplasia may be more prevalent in males than females. Cranial cruciate ligament injury affects males and females equally.



  • Spay or neuter at before sexual maturity/first heat cycle – between 4-5.5 months old


  • Small to medium sized breeds- neuter before sexual maturity 4-5.5 months
  • Large, giant and specific other breeds – early spay/neuter may predispose them to certain orthopedic problems and mild increase risk of developing certain cancers, waiting until they are 12-18 months old may be advised

The bottom line is to talk with your veterinarian. Together you will review the pro’s and con’s taking into consideration your pet’s species, breed, age and your risk tolerance.

Written by Dr Nichelle Peck.