Veterinarians have long agreed that neutering (castrating or spaying) our dogs is an important way to help control the stray population. Overall, it is also the best choice for their health and behavior. However, when to neuter is not a “one size fits all” decision.
Researchers at the UC Davis School of Veterinary Medicine completed a 10-year study examining the effects of neutering at different times on 35 different dog breeds. They found that some breeds have a higher risk of developing certain cancers and joint disorders if altered within their first year of life.
This Is The Most In-Depth Study On When To Neuter Dogs
Past research has yielded similar results, but only examined a few breeds. The UC Davis study covers 15 years of data from thousands of dogs.
The goal was to determine whether neutering, age of neutering, or differences in sex affect the occurrence of certain cancers and joint disorders across breeds.
The cancers in the study include:
- Lymphoma
- Hemangiosarcoma (cancer of the blood vessel walls)
- Mast Cell Tumors
- Osteosarcoma (bone cancer)
The joint disorders in the study include:
- Hip Dysplasia
- Cranial Cruciate Ligament Tears
- Elbow Dysplasia
The Surprising Results:
When a dog is neutered affects their risk for joint disease.
In most breeds, the risk of developing joint problems was not affected by the age of the dog at the time of neutering. However, three particular breeds, the Golden Retriever, Labrador Retriever and German Shepherd Dog, are big exceptions.
These dogs have a higher risk of one or more joint disorders when neutered before a year of age. The increase is particularly seen in dogs neutered by 6 months of age.
Body size matters.
Most larger breeds tend to have a higher risk of joint disorders, with two “giant” exceptions. Neutering at any age does not seem to affect rates of joint disease in Great Danes and Irish Wolfhounds.
As for small dog breeds, joint disorders generally do not increase with the age of neutering. And only two small breeds – the Boston Terrier and the Shih Tzu – show a significant increase in cancers.
Male and female dogs of the same breed may be affected differently by their age at the time of neuter.
Perhaps the most surprising results of all are the findings for female Golden Retrievers. This breed is known for very high cancer rates. While male Goldens show no increase in cancers due to neutering, females are two to four times more likely to develop one or more cancers if neutered than if left intact.
Neutering male and female Labrador Retrievers and German Shepherds does not appear to increase their cancer risks. As for smaller breeds, only male Boston terriers neutered before a year of age have a significant risk increase.
When Should You Neuter Your Dog?
Since there is no “one size fits all” answer for when to neuter your dog, lead study author Benjamin Hart recommends reviewing the findings for your breed and consulting with your veterinarian. This chart shows the risks of a dog acquiring joint disorders or cancers based on neutering age, breed, and sex.
For more in-depth data on how neutering affects specific joint disorders, cancers, and urinary incontinence in specific breeds, view the complete study in Frontiers in Veterinary Medicine.
Should you decide to keep your dog intact beyond six months of age, please take precautions to avoid pregnancy. Whether your pooch is male or female, he or she should be kept on a leash or monitored in the yard. Even electric fences are no match for a dog driven by hormones!
Toledo, United States.
