A 2024 study from the UC Davis School of Veterinary Medicine published in Frontiers in Veterinary Science updated breed‑specific guidance on when to spay or neuter dogs, analyzing data from 41 breeds and adding six that were not part of a 2013 study. Spay‑neuter recommendations now vary by breed and size, as large and giant breeds such as Golden Retrievers and German Shepherds show higher risks of joint disorders and certain cancers when neutered before reaching full physical maturity.

The paper recalibrates timing recommendations to reduce the risk of joint disorders and certain cancers that can follow early removal of reproductive organs. Researchers concluded that interruption of normal hormone production can shift bone growth and affect joint development, with implications for when surgery should be scheduled. While spaying and neutering have long-term health benefits, including increased lifespan, with some studies finding that spayed and neutered dogs tend to live longer than intact dogs, although exact percentage differences vary by study and population and are not specified in the UC Davis 2024 breed‑specific timing study, the timing of these procedures can significantly influence the risk of developing health issues later in life.

“The hormones are involved in setting the time when the growth plate of the leg bones close,” said Dr. Lynette Hart, Professor at the UC Davis School of Veterinary Medicine. Her comment ties the study’s central biological mechanism to the higher rates of hip and elbow problems and ligament tears seen in some breeds after early neutering.

Authors examined breeds across size categories, and the report lists several common breeds by name: Golden Retriever, Siberian Husky, German Shorthaired Pointer, German Wirehaired Pointer, Rhodesian Ridgeback, Newfoundland and Mastiff. The findings build on earlier work and offer updated, breed‑specific timelines intended to minimize adverse outcomes while balancing other health considerations. Approximately 80-90% of dog owners in the United States choose to spay or neuter their pets, reflecting a widespread commitment to improving pet health and managing population control.

Dr. Lynette Hart said the Golden Retriever results were unexpectedly stark. “One surprise was that the first breed that we started with just by accident, the Golden, in a way is the most troubling. The results are the most troubling,” she said, underscoring why breed‑level detail matters in clinical decisions about timing.

Dr. Benjamin Hart, Professor at UC Davis School of Veterinary Medicine, pointed to cancer risk among males as one of the tradeoffs the research weighs. “It’s 11% [of males] that come up with the cancers. So males right off the bat are a bit more — quite bit more susceptible to some of the cancers,” he said, highlighting that cancer outcomes are part of the calculus alongside joint disease.

The study’s authors traced how early neutering alters sex‑hormone exposure during the period when growth plates close. That altered timing can lengthen leg bones slightly and change how joints articulate, contributing to conditions such as hip dysplasia, elbow dysplasia, and cranial cruciate ligament tears, the report notes. This work is critical for informing veterinary practices, giving both veterinarians and owners vital information in a landscape where spay-neuter practices are evolving.

Researchers at UC Davis compared their 2024 findings to the 2013 study that first identified associations between early spay‑neuter and joint disorders in many large breeds. The new paper extends that work by incorporating six additional breeds and refining recommendations so veterinarians and owners can consider breed‑specific risk profiles when planning surgery.

Authors and clinicians speaking about the research emphasized owner engagement. “The big lesson that we’ve learned, kind of the overriding one, is that people really care about their dogs, and they will do anything to find out how to take better care of them and avoid making them at greater risk for these problems,” Dr. Lynette Hart said.

The study was published in Frontiers in Veterinary Science and summarized in an article by the American Kennel Club, which provided accessible coverage of the updated guidance and the breeds included.

The research does not replace individualized veterinary advice; rather, it supplies an expanded evidence base to help veterinarians and owners weigh the relative risks of joint disorders and certain cancers when selecting a timing strategy for sterilization.

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Original reporting: view the original article.