Age at gonadectomy and risk of overweight/obesity and orthopedic injury in a cohort of Golden Retrievers

PLoS One. 2019 Jul 17;14(7):e0209131. doi: 10.1371/journal.pone.0209131. eCollection 2019.


Introduction: In the United States, gonadectomy is common and widely promoted as a component of responsible pet ownership. The recent publication of several studies examining the effect of gonadectomy on future health has challenged long-held assumptions and recommendations for gonadectomy in companion animals. The purpose of this study was to characterize the associations between gonadectomy and two outcomes: overweight/obesity and orthopedic injuries, in a large prospective study of Golden Retrievers.

Methods: Age at gonadectomy was divided into four categories: intact (reference), ≤ 6 months, > 6 months ‒ ≤ 12 months, and > 12 months. Dogs with a Purina Body Condition Score of 7 or greater were classified as overweight or obese. Orthopedic injuries considered were the first instance of veterinary-reported cranial cruciate ligament injury and clinically evident osteoarthritis. We performed survival analyses on a cohort of Golden Retrievers to estimate the associations of interest using proportional hazards. We adjusted for age at study enrollment, owner-reported activity level, and dog's sex.

Results: Compared to intact dogs, all gonadectomy age categories showed increased risk for the development of overweight/obesity. (≤ 6 months, HR: 1.81, 95% CI: 1.36-2.40), p-value: <0.0001; 6 months to ≤ 12 months, HR: 2.21, 95% CI: 1.77-2.73, p-value: < 0.0001; > 12 months, HR: 1.56, 95% CI: 1.24-1.96, p-value: 0.0001). Compared to intact dogs, dogs who were ≤ 6 months at gonadectomy had increased risk for orthopedic injury (HR: 4.06, 95% CI: 2.15-7.67, p-value: <0.00001).

Discussion: This study presents prospectively acquired data demonstrating that gonadectomy is a risk factor for both overweight/obesity and chronic non-traumatic orthopedic injuries in a prospective cohort of Golden Retrievers. Our data suggest that gonadectomy at any age is a risk factor for overweight or obesity, but delaying gonadectomy until dogs are at least 6-12 months of age may help to decrease the risk for orthopedic injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Anterior Cruciate Ligament Injuries / etiology
  • Anterior Cruciate Ligament Injuries / veterinary*
  • Castration / adverse effects
  • Castration / veterinary*
  • Dog Diseases / etiology*
  • Dogs
  • Female
  • Male
  • Obesity / etiology
  • Obesity / veterinary*
  • Osteoarthritis / etiology
  • Osteoarthritis / veterinary*
  • Overweight / etiology
  • Overweight / veterinary*
  • Prospective Studies
  • Risk Factors
  • Sex Factors

Grants and funding

The Golden Retriever Lifetime study and this manuscript were made possible through financial support provided by the Morris Family Foundation, Blue Buffalo Cancer Research Foundation, Petco Foundation, Zoetis, Antech Inc., the Golden Retriever Foundation, the Hadley and Marion Stuart Foundation, Mars veterinary, generous private donors, and the Flint Animal Cancer Center, Colorado State University. The study is managed and executed by Morris Animal Foundation and several co-authors are employed by Morris Animal Foundation, however, final scientific content is written and approved independently of the entities that funded the study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.