Early Neutering May Be Bad For Larger Mixed-Breed Dogs

Researchers from the University of California, Davis just released study results that show heavier mixed-breed dogs may be at higher risks for joint disorders and problems if they’re neutered before they are a year old.

The debate about when to spay or neuter your dog has equal support for both sides of the earlier/later fence. But new research from researchers at the University of California, Davis believe that it may be best to wait until your larger mixed-breed dog is over a year old.

Related: What Is The Best Age To Neuter Your Dog?

This is because they found that mixed-breed dogs who weighed more than 44 pounds as adults were at higher risk for joint disorders if they were neutered before their first birthday. Dogs 43 pounds and under didn’t appear to have increased risk for joint issues.

It’s common to neuter dogs by the time they are 6-months-old. This study looked at 15 years’ worth of data from the thousands of dogs seen at the UC Davis Veterinary Medical Teaching Hospital. Lead Author Benjamin Hart said that since most dogs are mixed breeds, he hopes the study will allow dog parents to make informed decisions on when to spay or neuter.

Dr. Hart is a distinguished professor emeritus at the UC Davis School of Veterinary Medicine. He says that owners should weigh options carefully when adopting a puppy and deciding when to spay or neuter.

The researchers looked at common joint issues like hip and elbow dysplasia, as well as cranial cruciate ligament tears and knee injuries in five different weight categories. They also looked at the risks mixed-breed dogs had of developing cancers based on their weight categories; they found no increased risk based on weight as compared to dogs who were not spayed or neutered.

The risk of joint disorders for heavier dogs could be up to a few times higher than when compared to dogs who are not spayed or neutered. They found this was true for large mixed-breed dogs. As an example, in female dogs over 43 pounds, the risk jumped from 4 percent for intact dogs to 10-12 percent if spayed before a year of age.

Dr. Lynette Hart is a professor at the UC Davis School of Veterinary Medicine. She is also a co-author of the study and said that it’s important people look at all angles of spaying and neutering as the study brings about unique situations. Too often, Hart says, when adopting a mixed-breed puppy from a shelter, one has no idea how big the dog will actually become. It makes deciding when to spay or neuter tough, particularly when you know little to nothing about the dog’s parents.

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Many times, neutering is a requirement of an adoption process for shelters as well as breeders. The researchers believe that this policy should be looked at, and instead, shelters and breeders should consider requiring neutering a standard when dogs are a year or older if they are breeds that will grow into larger dogs. Dr. Hart believes this is especially important for those who raise service dogs, as joint disorders can significantly impact a dog’s ability to do its ‘job’ as well as impact its role as a family member.

The research team has previously conducted similar research and found health risks based on neuter age tended to vary greatly depending on dog breed, but size and weight may now need to be looked at, despite breed histories.