Trending News: When Should You Spay Or Neuter Your Dog?

Initially, this research resulted in a flurry of debates regarding the best age to spay or neuter your dog. This is understandable because to some it can be complicated to consider an alternative to the status quo paradigm. Regardless, the researchers set out to add more breed studies by examining over a decade of data involving thousands of dogs to provide owners with more information to help them make the best choices for their beloved pets. 

For this study, the researchers specifically examined the correlation between spaying/neutering a dog before reaching one year old and the risk of developing certain cancers such as those of the bones, blood vessels, lymph nodes, and mast cell tumors. The researchers also looked at correlations between joint disorders such as elbow or hip dysplasia, and cranial cruciate ligament tears. 

In dogs, joint disorders and cancers are of particular interest because these surgeries remove female and male sex hormones that play key roles in important body processes such as the closure of bone growth plates. 

The researchers collected data from UC Davis Veterinary Hospital’s records which included over 200 cases for 5 breeds of dogs weighing more than 44 pounds spanning from January 2000 through December 2020. The five popular breeds of dogs this study focused on were: Siberian Husky, Newfoundland, Rhodesian Ridgeback, Mastiffs, and German Short/Wirehaired Pointers. 

"This is a shift from a long-standing model of early spay/neuter practices in the U.S. and much of Europe to neuter by 6 months of age, but important to consider as we see the connections between gonadal hormone withdrawal from early spay/neuter and potential health concerns,” said Professor Lynette Hart of the School of Veterinary Medicine, who is also one of the lead authors. 

"We're invested in making contributions to people's relationship with their animals," said Benjamin Hart, distinguished professor emeritus and co-lead author. "This guidance provides information and options for veterinarians to give pet owners, who should have the final decision-making role for the health and well-being of their animal."

The researcher found major differences among the breeds for developing cancers and joint disorders when they had these surgeries at an early age. 

The analysis revealed that male Mastiff breeds had increased cranial cruciate ligament tears and lymphoma; male and female pointer breeds had elevated joint disorders and increased cancers. Female Ridgeback breeds had increased risks for mast cell tumors with very early neutering, and female Newfoundland breeds had heightened risks for joint disorders. However, Siberian huskies showed no significant effects on joint disorders or cancers.

According to the researchers, updating the guidelines emphasizes the importance of personalizing important decisions to include considering the breed of the dog as well as sex and context. 

You can view a table representing suggested age guideline updates for all 40 breeds by clicking here. The sizes of the 40 dogs studied range from toy breeds such as the Chihuahua to giant breeds such as the Great Dane.