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Make an Educated Decision

Aug 01, 2018 09:50AM ● By Louisa Asseo

Dr. Louisa Asseo, owner of Oasis Veterinary Hospital, 6635 Alhambra Ave, Suite 100, 925.954.8087

Make an Educated Decision

When is the Appropriate Time to Spay and Neuter Your Pet?

Dr. Louisa


In recent years, there has been a lot of debate about the right time to spay or neuter your dog.  In shelters and rescues, spaying and neutering are done as early as possible. Shelters adopt this policy to prevent more unwanted pregnancies and, therefore, more puppies and kittens in the shelters. In private practice, the trend used to be to recommend spaying or neutering dogs after completion of the core vaccines at 16 weeks but before the onset of puberty at six months. This has been a discussion point in recent years.  Now it seems that the “right” answer depends on whom you speak with and which article you read. 

In 2013, an article by de la Riva and Hart concluded that early spaying and neutering resulted in more cancers and joint problems in dogs.  However, the conclusions were very skewed.  Was cancer higher in these dogs BECAUSE we spayed and neutered them, thus keeping them healthier and alive long enough to reach the age where cancers are seen? This article also did not address what is meant by an “early” spay or neuter. Does this mean altering them at eight weeks old or six months old?

There are definite health benefits to spaying and castrating aside from the obvious one of preventing pregnancy.  Allowing a female dog to go through even one heat cycle can put her at risk for uterine infection (pyometra), which is treated through emergency surgery and aggressive support care. In addition, the risk of mammary tumors increases for female dogs after their first heat cycle.  Male dogs can show territorial or aggressive behaviors if not castrated and have a bigger tendency to want to roam, thus putting them in danger of vehicular trauma and getting lost. 

In support of delaying spaying or castrating, a study by Duerr and Duncan in 2007 demonstrated a correlation between early spay and castration and an increased incidence of knee injury.  This study demonstrated that dogs neutered earlier than 6 months had different joint conformations that can be associated with cruciate ligament tears.  It is still important to remember that demonstrating a correlation does not always mean causation.

So, how do you decide what is right for your dog? The answer is not simple for females.  For small breed dogs with a decreased risk of joint problems, perhaps we can still spay at six months and avoid the risks of a first heat cycle.  For larger breed dogs and those predisposed to joint issues, perhaps we can delay the spay until they are a bit more skeletally mature. However, then you assume the risks of pyometra and mammary masses in the future.  For males, the answer can be a bit simpler.  Delaying the castration until they are a bit more skeletally mature may be the safest option.  Have this discussion with your veterinarian to identify the risk factors for your dog.  Together, you can make an educated decision to help your pet live a long, happy, and healthy life.