Paw Prints the Magazine

When is the right time to have Fido fixed?

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By Stacy E. Smith

At some point, most of us are faced with the decision of whether or not to spay or neuter our pets. We’ve had lots of pets in our home and have had ALL of them spayed and neutered, and I believe the vast majority of our readers spay and neuter their pets as well.

To be clear at the outset, this is not an article about whether or not to have your pets spayed or neutered. While that is clearly a personal decision, we STRONGLY believe in spaying and neutering and would never suggest otherwise.

Traditionally, it has been common for pets to be “fixed” at around 6 months old, with the exception of those under the care of shelters and rescues which commonly have the procedure done much earlier.

“Common knowledge” suggests that the benefits of doing so at an early age outweigh the risks. As is often the case, tradition takes precedence in the decision-making process even after evidence to the contrary has been discovered.

An objective reading of the veterinary medical literature reveals a complex situation with respect to the long-term health risks and benefits associated with spay/neuter in dogs. Specifically, a Rutgers University study that shows spay/neuter correlates with both positive AND negative health effects in dogs. It also suggests how much we really do not yet understand about this subject.

I am providing the basic details here, but will also provide a link to the full study at the end of the article for anyone that would like to read it.

Male Dogs:

On balance, it appears that no compelling case can be made for neutering most male dogs, especially immature male dogs, 6-12 months, in order to prevent future health problems.

On the positive side, neutering male dogs

• eliminates the small risk (probably less than 1%) of dying from testicular cancer,
• reduces the risk of non-cancerous prostate disorders,
• reduces the risk of perianal fistulas,
• may possibly reduce the risk of diabetes (data inconclusive).

On the negative side, neutering male dogs

• if done before 1 year of age, significantly increases the risk of osteosarcoma (bone cancer); this is a common cancer in medium/large and larger breeds with a poor prognosis.increases the risk of cardiac hemangiosarcoma by a factor of 1.6;
• triples the risk of hypothyroidism;
• increases the risk of progressive geriatric cognitive impairment;
• triples the risk of obesity, a common health problem in dogs with many associated health problems;
• quadruples the small risk (<0.6%) of prostate cancer;
• doubles the small risk (<1%) of urinary tract cancers;
• increases the risk of orthopedic disorders;
• increases the risk of adverse reactions to vaccinations.

Female Dogs:

For female dogs, the situation is more complex. The number of health benefits associated with spaying may exceed the associated health problems in some (not all) cases. On balance, whether spaying improves the odds of overall good health or degrades them probably depends on the age of the female dog and the relative risk of various diseases in the different breeds.

On the positive side, spaying female dogs

• if done before 2.5 years of age, greatly reduces the risk of mammary tumors, the most common malignant tumors in female dogs;
• nearly eliminates the risk of pyometra, which otherwise would affect about 23% of intact female dogs; pyometra kills about 1% of intact female dogs;
• reduces the risk of perianal fistulas;
• removes the very small risk (less than 0.5%) from uterine, cervical, and ovarian tumors.

On the negative side, spaying female dogs

• if done before 1 year of age, significantly increases the risk of osteosarcoma (bone cancer); this is a common cancer in larger breeds with a poor prognosis;
• increases the risk of splenic hemangiosarcoma by a factor of 2.2 and cardiac hemangiosarcoma by a factor of >5; this is a common cancer and major cause of death in some breeds;
• triples the risk of hypothyroidism;
• increases the risk of obesity by a factor of 1.6-2, a common health problem in dogs with many associated health problems;
• causes urinary “spay incontinence” in 4-20% of female dogs;
• increases the risk of persistent or recurring urinary tract infections by a factor of 3-4;
• increases the risk of recessed vulva, vaginal dermatitis, and vaginitis, especially for female dogs spayed before puberty;
• doubles the small risk (<1%) of urinary tract tumors;
• increases the risk of orthopedic disorders;
• increases the risk of adverse reactions to vaccinations.

One cannot ignore the findings of increased risk in spayed and neutered dogs from osteosarcoma, hemangiosarcoma, hypothyroidism, and other less frequently occurring diseases.

The traditional spay/neuter age of six months as well as the modern practice of pediatric spay/neuter appear to predispose dogs to health risks that could otherwise be avoided by waiting until the dog is physically mature (12-24 months), or perhaps in the case of many male dogs, foregoing it altogether unless medically necessary.

Across-the-board recommendations for all pet dogs do not appear to be supportable from findings in the veterinary medical literature.

One thing is clear – much of the spay/neuter information that is available to the public is unbalanced and contains claims that are exaggerated or unsupported by evidence. Rather than helping to educate pet owners, much of it has contributed to common misunderstandings about the health risks and benefits associated of spay/neuter in dogs.

After reading this study, we made the personal choice not to spay or neuter our pets before they are one year old unless it is medically necessary or there are behavior (aggression) issues that warrant the procedure earlier.

What I hope this article provides is the information most pet owners do not receive. It is important that pet owners, along with their veterinary medical team, make informed decisions instead of relying on “common knowledge” or old wives tales. Who could ask for more?

Click here to read the full study.

Tags: female dogs, male dogs, neuter, osteosarcoma, pet health, spay