Why We Recommend Waiting to Spay or Neuter Your Dog
Recent research studies have significantly impacted recommendations for when to spay or neuter your dog. Historically, spaying and neutering was promoted as an effective method of managing the over-population from accidental breeding resulting in unwanted dogs and cats, and was encouraged to be done between the age of 6-9 months, before sexual and physical maturity. Spaying of females reduces the risk of pyometrea and mammary tumors. Neutering of males reduces the risk of testicular cancer and may reduce the urge to roam. However, long-term overall health and behavioral benefits and risks have since been studied and evaluated.
Research sponsored by the AKC indicates there may be long-term health benefits to spaying or neutering dogs afterthey have passed through physical and sexual maturity. Benefits have been shown to include a reduction in orthopedic health problems (hip and elbow), a possible reduction in certain cancers in specific breeds, as well as possible improved behavior.
Gonadal hormones significantly contribute to the control of the closure of bone growth plates, and with the elimination of testosterone in males, or estrogen in females through neutering, may result in a significant increase hip and elbow dysplasia and cranial cruciate ligament tear (CCL).
A landmark study led by Dr. Benjamin L Hart on Golden Retrievers, on early neuter (before 12 months), late neuter (after 12 months), and intact, shows the following:
- An increased likelihood of hemangiosarcoma, lymphoma, mast cell tumors, and canine cruciate ligament (CCL) rupture in neutered dogs.
- The risk of development of hip dysplasia doubles, and disease occurs at a younger age in the early-neuter group compared to both the intact and late-neuter group.
- No occurrence of CCL disease was observed in intact male or intact female dogs, or in late-neutered females. In early-neutered dogs, the incidence of CCL was 5.1 percent in males and 7.7 percent in females, suggesting that neutering prior to sexual maturity significantly increases a dog’s risk of developing CCL disease.
- With respect to cancer, cases of lymphoma were 3-fold greater in the early-neutered males. Interestingly, incidence of mast cell tumors (male and female dogs) and hemangiosarcoma (female dogs only) were highest in the late-neuter group.
- Recent data also shows early neuter may lead to increased tendency towards shyness and insecurity.
Research conducted by the vet school at the University of California, Davis also arrived at the same conclusion for large breed dogs: wait until after 12 months of age to spay or neuter your dog. Their study of 3000 deceased dogs with full health records showed an increase in hip joint disorders in early spay/neuter of 4x the rate in late spay/neuter or intact dogs.
Based upon information from these studies, we here at TPL strongly believe that the timing of spay and neuter does, in fact, have a significant impact on the quality and longevity of the life of your dog. We recommend waiting until females are between 12-18 months of age, and males are between 18-24 months of age.
01488-A: Health Implications of Spay and Neuter: Golden Retriever and Labrador Retriever, Research Grant July 1, 2010-June 1, 2011, Dr. Benjamin L. Hart, DVM, PhD