Most of us have lived by the “neutering dogma” that suggests spaying and neutering should be performed by age 6 months, and in females, certainly before the first heat.
While this is still the rule of thumb for rescue organizations whose goal is to control the homeless pet population, recent research is offering some interesting statistics that provide canine aficionados with some food for thought.
What follows are some studies presented in a webinar by Dr. Nancy Kay called “Changing perspectives about Canine Spay and Neuter.” Click on the title for more detailed information.
The objective of this study was to determine the relationship between the time of spay/neuter and the development of sarcoma; 683 Rottweiler owners participated in the study.
The conclusion of this study is that delaying spaying and neutering protects Rottweilers from developing bone sarcoma.
Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers
Gretel Torres de la Riva, et al,
PLoS One – February 2013
The objective of this study was to review the medical records of 759 golden retrievers between the ages of 1 – 8 to determine if early neutering (before 1 year of age) versus late neutering (after 1 year of age) had any effect on the incidence of hip dysplasia, cruciate ligament tear, lymphosarcoma, hemangiosarcoma and mast cell tumors.
Mast Cell Tumors
For all the diseases that were analyzed, incidence of the disease was significantly influenced by neutering. Age and gender also played a role. Orthopedic issues may be related to alteration of growth plate closure caused by neutering.
Long-Term Health Effects of Neutering Dogs: Comparison of Labrador Retrievers with Golden Retrievers
Benjamin L. Hart, et al
Plos One- July 2014
This study fascinated me, as I expected the results to be similar for golden and Labrador retrievers – but they weren’t!
Hospital records of 1,015 golden retrievers and 1,500 Labrador retrievers, between the ages of 1 – 8 years were studied to analyze the occurrence of hip dysplasia, cruciate ligament disease, elbow dysplasia, lymphosarcoma, hemangiosarcoma and mast cell tumors.
The study concluded that:
In this study, 2,505 Vizsla owners participated in a survey gathering information on neutering status and age at diagnosis of various cancers and behavior disorders.
Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence
Benjamin Hart, et al
Veterinary Medicine & Science – May 2016
This study used the hospital records of 1,170 dogs with a mix of neutered and intact males and females looking for various types of cancer, joint disorders, and urinary incontinence.
Conclusions of the study:
Reproductive Capability is Associated with Lifespan and Cause of Death in Companion Dogs
Jessica M. Hoffman, et al
PLoS One – April 2013
This study fascinated me in that it included 185 different breeds of dogs and the outcome of the study was completely opposite of some of the previously mentioned breed specific studies.
This study looked at the age and cause of death in 70,574 dogs where 43.6% were intact and 56.4% were neutered. (Age at the time of neutering was not accessed.)
Results of the study:
The conclusion of this study was that neutered dogs live longer than intact dogs.
Impact of neutering (male and female) on behavior
The speaker also expressed these thoughts regarding the impact of neutering on behavior.
Urine marking: Neutering can reduce the incidence of urine marking by 60%.
Mounting: Neutering can decrease mounting behavior by 50 – 60%.
Roaming: There is up to a 90% decrease in roaming in neutered dogs.
Aggression: Effects of neutering male dogs.
Aggression: Effect of Neutering on Female Dogs
As Dr. Kay stated in her webinar, there is no “one size fits all” response as to whether dogs should be neutered, or if they are neutered, at what age.
Factors to keep in mind:
Intended use of the dog.
Owners personal history.
We don’t have data for all breeds. But there is compelling evidence for rethinking automatic neutering at 6 months for some breeds.
Other breeds or mixed breeds are an entirely different issue. Current data (see Reproductive Capability is Associated with Lifespan and Cause of Death in Companion Dogs) shows that neutered pets live longer than unneutered pets.
Neutering can impact behavior (urine marking, mounting, etc.)
Whether or not to neuter (or at what age) is on longer a simple question to answer. Remain open-minded, do your research, be a responsible dog owner and do what is best for your specific situation.