The Health Implications of Early Spay and Neuter
In the United States spaying and neutering is generally recommended as the standard of care by veterinarians, and for years the procedures have been completed prior to maturity. These recommendations are influenced in part by concerns about pet-overpopulation. However, research is indicating that the timing of spay and neuter in dogs has implications for the long-term health.
In a research study supported by the AKC Canine Health Foundation, Dr. Ben Hart and colleagues from the University of California at Davis used a large veterinary database to determine what exactly the implications of neutering might be for a breed of dogs that is one of the most popular in the U.S. – the Golden Retriever. They compared health outcomes for dogs who were neutered early (before 1 year of age), neutered late (after 1 year of age), or left intact. The results were fascinating: timing of spay and neuter significantly affected the risk of a dog developing serious health problems. This information has implications for both the practice of veterinary medicine in the US and our understanding of the role of gonadal hormones in human health.
Published in the February 2013 issue of PLOS One, this study showed that early neutering more than doubled the risk of hip dysplasia in male, but not female golden retrievers. Early neutering also significantly increased the risk of both cranial cruciate ligament tear (CCL) and lymphosarcoma (LSA) in dogs of both sexes. In female dogs, late neutering also increased the risk of hemangiosarcoma (HSA) and mast cell tumor (MCT). There were no mast cell tumors in intact female dogs.
For decades, spaying and neutering prior to sexual maturity became the default recommendation of the veterinary profession to address pet overpopulation in the United States. Consensus opinion is still that spay and neuter remain the most effective means to control the pet population. What is at stake here is balancing population control with optimal health in pet dogs, and this research suggests timing of spay and neuter may be a means of accomplishing this goal.
Because questions remain, the AKC Canine Health Foundation recently funded a second phase of this research topic. The additional work will evaluate Labrador Retrievers, German Shepherd Dogs and Dachshunds. Rottweilers, Chihuahuas, Standard Poodles and Miniature Poodles will be included if resources and patient data are available. The expectation is that by including multiple breeds in phase two, researchers will be able to develop a generalized understanding of the impact of early spay and neuter on disease risk in dogs. This in turn will enable veterinarians and breeders to make data-driven recommendations regarding timing of spay/neuter procedures to reduce the risk of development of multiple devastating diseases.
This work was funded by AKC Canine Health Foundation grant 1488-A. The continuing work is funded by grant 1840.
Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers (full-text version available through open access journal Plos One.)
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