Researchers at the University of California, Davis, have issued new guidelines on the optimal age to neuter 40 popular dog breeds, with recommendations tailored by breed and sex. The latest study, published in Frontiers in Veterinary Science, builds on initial findings from 2013 which indicated that early neutering of golden retrievers increases the risk of joint diseases and certain cancers.
The original study sparked significant debate over the ideal age for neutering other dog breeds. Professors Lynette and Benjamin Hart, leading the research at UC Davis School of Veterinary Medicine, expanded their investigation by analyzing over a decade’s worth of data from thousands of dogs treated at the UC Davis veterinary hospital. Their objective is to equip pet owners with more comprehensive information to make informed decisions for their dogs.
The researchers examined the link between neutering or spaying dogs before one year of age and the risk of developing cancers, including those of the lymph nodes, bones, blood vessels, and mast cell tumors, as well as joint disorders like hip or elbow dysplasia, and cranial cruciate ligament tears. These health issues are particularly relevant because neutering removes sex hormones critical for processes such as bone growth plate closure.
The most recent study focused on five breeds: German shorthaired/wirehaired pointer, mastiff, Newfoundland, Rhodesian ridgeback, and Siberian husky. The data encompassed over 200 cases for each breed, weighing more than 20 kg (44 pounds), from January 2000 to December 2020, based on records from the UC Davis veterinary hospital.
The Harts emphasized that their updated guidelines highlight the necessity of personalized decisions regarding dog neutering, taking into account breed, sex, and individual circumstances. A comprehensive table detailing guidelines for all 40 studied breeds, including the newly added ones, is available.
Health Risks Vary Among Breeds
“It’s always complicated to consider an alternate paradigm,” said Professor Lynette Hart. “This represents a shift from the long-standing practice of early spay/neuter at six months of age, common in the U.S. and much of Europe, to considering the health implications of early gonadal hormone withdrawal.”
The study revealed significant differences in health risks among breeds when neutered early. Male and female pointers exhibited elevated joint disorders and cancer risks; male mastiffs had increased rates of cranial cruciate ligament tears and lymphoma; female Newfoundlands faced higher risks of joint disorders; female Ridgebacks had a heightened risk of mast cell tumors with very early neutering; and Siberian huskies showed no significant effects on joint disorders or cancers.
“We’re dedicated to enhancing the human-animal bond,” said Benjamin Hart, distinguished professor emeritus. “This guidance offers veterinarians information and options to present to pet owners, who should ultimately make the final decision for their animal’s health and well-being.”
