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

Abstract

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.

Desexing Dogs: A Review of the Current Literature

“…A large body of literature exists covering various long-term health aspects of desexing, with most papers focusing on individual disease and/or cause of death risks; however, many of the existing studies on individual disease risks are limited to one breed or to a relatively low number of breeds [104,112,[114][115][116][117][118][119][120].…”

“…Disorders that have been reported as being more common in desexed dogs include craniate cruciate ligament (CCL) injury, hip dysplasia (HD), elbow dysplasia (ED), and osteoarthritis in general. The most consistently reported joint disorder with an increased risk in gonadectomized dogs of both sexes is CCL injury, which has been reported both in the general population and in individual breeds such as German Shepherds as well as Golden and Labrador Retrievers [114,116,117,120,162,169,170], and with some of the available studies reporting an increased risk in dogs that were desexed before puberty.…”

“…Other joint disorders that have been found to occur more commonly in desexed dogs are HD in gonadectomized male Golden Retrievers [117]; overall joint disorder risk (HD, ED, CCL rupture) in gonadectomized German Shepherds of both sexes [120], Golden Retrievers of both sexes [114], and female Labrador Retrievers [114]; ED and CCL rupture in male Labrador Retrievers that were gonadectomized before six months of age [114]; and CCL injury and osteoarthritis in Golden Retrievers of both sexes that were gonadectomized before six months of age [116].…”

“…There are multiple studies from a wide variety of geographic areas linking desexing to an increased risk of obesity in dogs. These studies include dog populations from the US, the UK, Continental Europe, Australia, China, and Japan [116,[183][184][185][186][187][188][189][190][191]. While one recent study performed in Danish dogs found an increased obesity risk associated with desexing that was limited to male dogs [189], most other available studies find that the effect is present in both sexes.…”

SNP‐based heritability and genetic architecture of cranial cruciate ligament rupture in Labrador Retrievers

“…2008; Simpson et al . 2019). Dog breeds that are considered high risk for experiencing CCLR mostly include large‐ and giant‐breed dogs, such as the Labrador Retriever (LR), Rottweiler and Newfoundland (Wilke et al .…”