Spaying or Neutering

Because I know many of you will be contemplating this issue, here is some information regarding spaying and neutering. I do have a lengthy article if you'd like me to send it to you.

On the positive side, neutering male dogs
• eliminates the small risk (probably <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

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 ( 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 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.