“Thus far, our findings have not associated an increase in diseases due to spaying or neutering in small breeds, and in the other breeds, disease risk was dependent on gender and whether spay or neuter surgery was performed before or after
1 year of age,” says Dr. Hart. “There is much misconception related to the impact neutering has on an animal and whether the age of neutering makes a difference. We knew we needed the research to be breed-specific rather than generalizing across breeds.”
In one of their publications, Dr. Hart’s team compared the long-term health effects of neutering in Labrador Retrievers and Golden Retrievers and found that neutering before 6 months of age doubled the incidence of one or more joint disorders in Labradors, and increased the risk in Goldens by four to five times. Spaying female Goldens through 8 years of age increased the rate of at least one cancer by three to four times that of intact females.
Increased Incidence of CCL Rupture
The decision whether to neuter or spay a dog often relates to the dog’s purpose. A German Shepherd Dog being campaigned at dog shows is not eligible for neutering or spaying because conformation involves judging dogs for their breeding potential. Dogs that compete in herding trials, obedience or rally, agility, tracking, and Schutzhund may be neutered or spayed, as these performance events are exempt from the breeding purpose that governs dog shows. However, owners may wish to avoid increasing the risk of a joint disorder such as hip dysplasia or CCL, as this could interfere with performance.
People who buy German Shepherd Dogs for companions may want to neuter or spay their dog to help prevent unwanted litters, to avoid bitches coming into season, and to lessen aggression and roaming tendencies in males, though Dr. Hart says evidence shows that neutering males after 1 year is as effective in controlling aggression as neutering before 6 months of age.
Neutering or spaying German Shepherd Dogs training for police or military work is optional. However, it is important that these dogs be healthy and fit to do their jobs, and neutering or spaying before 6 months of age could increase the risk of a debilitating joint disorder such as hip dysplasia or CCL.
Among all German Shepherd Dogs studied, hip dysplasia, a frequent disease in the breed, is doubled in risk to 7 to 8 percent by early spaying or neutering. However, CCL occurs in less than 1 percent of intact dogs but is increased in risk to 8 to 12 percent with early spay-neuter surgeries, resulting in this disease being the main joint disorder impacted by early neutering in German Shepherd Dogs.
As the most common joint disorder in spayed or neutered dogs, CCL rupture also can shorten a dog’s working career, is expensive to treat and requires weeks of rehabilitation. A critical stabilizer of the stifle (knee) joint, the CCL functions as a rope as it stabilizes the femur (thighbone) to the tibia (shinbone), preventing the stifle bone from shifting during activity. Without the normal CCL stabilization, a dog’s movement is compromised and painful osteoarthritis develops.
In intact male German Shepherd Dogs, 6.6 percent were diagnosed with at least one joint disorder. The main joint disorder reported was hip dysplasia, which results from a loose connection between the pelvis socket, or acetabulum, and the thighbone ball, or femur head, which creates laxity in the hip joint. Degenerative joint disease, or osteoarthritis, commonly accompany this disease, causing pain and disability.
Male German Shepherd Dogs neutered before 6 months of age had an incidence rate of 20.8 percent of developing one joint disorder — three times greater than in intact males. In dogs neutered from 6 to 11 months of age, the incidence was 16.4 percent — two times greater than in intact males. Although CCL rupture occurred in less than 1 percent of intact males, in dogs neutered before 6 months of age and from 6 to 11 months of age, the rate increased significantly to 12.5 percent and 8.3 percent, respectively.
Similarly, intact female German Shepherd Dogs showed an incidence rate of 5.1 percent of having at least one joint disorder. In contrast, those spayed before 6 months of age had an incidence rate of 12.5 percent — more than double that of intact females. In those spayed between 6 to 11 months of age, the rate was almost 17 percent — three times higher than in intact females. CCL, which was diagnosed in less than 1 percent of intact females, occurred in 4.6 percent of females spayed before 6 months of age and in 8.3 percent spayed between 6 and 11 months of age.
Because joint disorders can be related to body weight, the researchers also looked at whether the increased weight of neutered dogs could be responsible for CCL rupture, but they did not find a connection. Using a body condition score (BCS) based on a scale of 1 to 9, with 5 being ideal, they compared the body condition of neutered males with CCL ruptures to neutered males without CCL ruptures and found that the median BCS for both was 5. The median BCS for spayed females with CCL ruptures was 5.75 compared to spayed females without CCL ruptures having a BCS of 5.
“We think that early neutering prevents the gonadal hormone secretion that normally stimulates closure of long-bone growth plates as a dog approaches maturity,” Dr. Hart explains. “The bones grow slightly longer than normal, which, in turn, disrupts joint alignment enough to lead to clinically apparent joint problems in some dogs.”
Elbow dysplasia was virtually nonexistent in intact and neutered German Shepherd Dogs. This condition is caused by growth disturbances in the elbow joint due to a misalignment of growth between the two bones in the foreleg between the radius (elbow) and ulna (wrist).
A noteworthy finding was that “dogs of either sex neutered after 1 year of age did not have significantly more joint disorders compared to intact dogs,” Dr. Hart says.
Risks Related to Urinary Incontinence & Cancer
Urinary incontinence is a disorder mainly affecting elderly female dogs in which they involuntarily pass urine. It is mostly diagnosed in neutered large-breed dogs. As expected, the condition was not reported in intact female German Shepherd Dogs, yet 7 percent of females spayed before 1 year of age were incontinent in their elderly years.
Fortunately, of the cancers followed in German Shepherd Dogs through age 8, there were few reports regardless whether a dog was intact or neutered. The research team cautioned that cancer rates could increase at later ages, though they did not study this.
Mammary cancer was tracked through 11 years of age because this type of cancer characteristically occurs later in life. About 4 to 5 percent of intact females and those spayed from 2 through 8 years were diagnosed with mammary cancer in contrast to no cases diagnosed in females spayed before 6 months of age.
Spaying has been attributed to helping to reduce the risk of mammary cancer, though a 2012 published study found neutering provided no apparent protection against mammary cancer. Dr. Hart notes that the protective factor could be breed specific. Regardless, in German Shepherd Dogs, the incidence of mammary cancer is fairly low.
A Proactive Preventive Approach
Given the results of this study showing the increased incidence of CCL rupture and urinary incontinence in German Shepherd Dogs that had early spay-neuter surgeries, breeders should consider the pros and cons before deciding the best age to recommend that puppy buyers spay or neuter their dogs. The purpose of a dog also should be considered in determining what is best for a companion dog, a working police dog, or a show or sporting competitor could be different.
A German Shepherd Dog that is neutered or spayed before 1 year of age and has a CCL rupture could be out of commission for months for surgery and rehabilitation. Urinary incontinence is an inconvenient disorder for owners to deal with because it requires frequent cleaning of urine from floors and bedding. It also is attributed to dogs being relinquished to shelters.
