A study published by the Journal of the American Veterinary Medical Association compared the health and behavior outcomes for dogs that had hormone-sparing sterilization procedures with sexually intact dogs or dogs that had undergone traditional castration or spay. Dr. Chris Zink and colleagues analyzed owner surveys for over 6,000 dogs, which had been distributed mainly by Good Dog.
They found that dogs that had longer lifelong exposure to natural hormones:
- had reduced odds of health problems and problematic and nuisance behaviors;
- lived longer; and
- exhibited the benefits of normal hormones regardless of reproductive status.
Dogs that have been sterilized by a vasectomy or ovary-sparing spay (hysterectomy) have lifetime exposure to normal hormones, as do dogs that have not been sterilized at all. But dogs that received a spay or neuter late in life may also get some of the health benefits of natural hormones.
The new study generally reflects past research reporting a number of serious health issues related to the loss of hormones resulting from spay and neuter (castration). Orthopedic conditions, cancers, immune diseases like diabetes, overweight, incontinence, and behavior issues (aggression, anxiety, fear) are more common in dogs that had been spayed or neutered when compared to intact dogs. Diseases of the sex organs (such as prostate diseases and mammary tumors) are of course more common in intact dogs since the reproductive organs are removed during spay and neuter surgery.
The research led by Dr. Zink is the first to include dogs that have undergone hormone-sparing sterilization. This study clarifies that it is the lack of normal hormones after spay or neuter that is related to the health and behavior issues. Hormone-sparing sterilization procedures were also highlighted as important options for pet owners.
The authors state: “Given the relatively low risk of these alternative surgeries, particularly in the hands of experienced veterinary practitioners, veterinarians might consider offering these alternative reproductive surgeries to allow dogs to obtain these benefits without experiencing unintentional reproduction.”