Some dog breeds have a higher risk of developing certain cancers and joint disorders if neutered or spayed within their first year of life. Until now, studies had only assessed that risk in a few breeds.
But a new, 10-year study by US researchers— published in Frontiers in Veterinary Science—examined 35 dog breeds and found vulnerability from neutering varies greatly depending on the breed.
“There is a huge disparity among different breeds,” said lead author Benjamin Hart, distinguished professor emeritus at the UC Davis School of Veterinary Medicine.
Professor Hart said there is no “one size fits all” when it comes to health risks and the age at which a dog is neutered.
“Some breeds developed problems, others didn’t. Some may have developed joint disorders but not cancer or the other way around.”
Researchers analysed 15 years of data from thousands of dogs examined each year at the UC Davis Veterinary Medical Teaching Hospital to try to understand whether neutering, the age of neutering, or differences in sex when neutered affect certain cancers and joint disorders across breeds.
In most breeds examined, the risk of developing problems was not affected by age of neutering.
Researchers found that vulnerability to joint disorders was related to body size.
“The smaller breeds don’t have these problems, while a majority of the larger breeds tend to have joint disorders,” co-author Lynette Hart said.
One of the surprising exceptions to this was among the two giant breeds—great Danes and Irish wolfhounds—which showed no increased risk to joint disorders when neutered at any age.
Researchers also found the occurrence of cancers in smaller dogs was low, whether neutered or kept intact.
Another important finding was that the sex of the dog sometimes made a difference in health risks when neutered.
This study suggests that dog owners should carefully consider when and if they should have their dog neutered.
“We think it’s the decision of the pet owner, in consultation with their veterinarian, not society’s expectations that should dictate when to neuter,” Professor Hart said. “This is a paradigm shift for the most commonly performed operation in veterinary practice.”