Last week, I wrote about some recent studies on possible behavioral changes that result from spaying neutering including a higher incidence of timidity, excitability, submissive urination, aggression, hyperactivity, fear biting, separation anxiety, and fear of noises in Vizslas that were spayed or neutered before six months of age. If the dogs were spayed or neutered after six months, there was no increased risk of these behaviors, however, thunder storm phobias were higher in neutered dogs than in non-neutered dogs regardless of the age of neutering.
There have been several other recent research projects focusing on the impact of spaying and neutering that have challenged some long-held beliefs and assumptions. One study, led by Dr. Benjamin L. Hart at the University of California, Davis, was financed by the AKC Canine Health Foundation. Entitled, "Health Implications in Early Spay and Neuter in Dogs," the study reports that the results "have the potential to significantly impact recommendations for spaying and neutering dogs in the United States. Most dogs in the United States are spayed or neutered, and for years the procedures have been completed prior to maturity. The study, published in the prominent, open access journal PLOS One, suggests that veterinarians should be more cautious about the age at which they spay and neuter in order to protect the overall health of dogs."
As with the research I wrote about last week, this one focused on one breed of dogs, Golden Retrievers, to evaluate the incidence of cancer and joint problems. The study focused on possible relationships to neutering status (spayed/neutered versus intact), and/or the dog's age at the time of spaying or neutering - either early (before 12 months of age) or later (12 months and older). The findings in this study are consistent with previous research, demonstrating that there is an increased likelihood of several cancers (hemangiosarcoma, lymphoma and mast cell tumors), as well as an increase in cruciate ligament (CCL) ruptures in neutered dogs.
Interestingly, there was no occurrence of CCL disease in intact males, intact females, or late-neutered females. In early-neutered females, the incidence of CCL is 7.7 percent and in early-neutered males, it occurs at 5.1 percent. Further, this study demonstrated a higher incidence of hip dysplasia-actually doubling the risk of hip dysplasia, and the disease occurring at an earlier age in the early-neutered dogs as compared with late-neutered and intact (non-neutered) dogs. This would suggest that sexual maturity benefits the dogs' structural health, significantly lowering the risk of a dog developing hip dysplasia and CCL disease (a debilitating, painful and costly condition to treat).
To quote from the study, "'Dr. Hart's landmark study is the first to provide evidence for when to spay or neuter dogs. For years the veterinary community has been aware that early-spay and neuter may impact orthopedic health in dogs. Through a very detailed analysis and inclusion of body condition score as a risk factor, Dr. Hart was able to show that timing of spay and neuter does indeed have health implications,' said Dr. Shila Nordone, Chief Scientific Officer for the AKC Canine Health Foundation."
As I wrote last week, I'm not recommending that we stop spaying and neutering dogs.
But I do believe that dog owners should have information to weigh the long term risks versus the benefits of neutering, and determine whether to put off the surgery until after the dog has reached sexual maturity. There is much more to be learned. Stay tuned for more in the future.
Gail Fisher, author of "The Thinking Dog," runs All Dogs Gym & Inn® near Manchester-Boston Regional Airport. To suggest a topic for this column, email firstname.lastname@example.org or write c/o All Dogs Gym, 505 Sheffield Rd., Manchester, NH 03103.