Spaying and neutering re-visited

Recently I have been made aware of people being pushed to spay & neuter their animals on the basis that this reduces the risks of cancer. My previous blog should have laid it out quite clearly, but here are some facts:

Positive for male neutering

1. eliminates the small risk (probably < 1%) of dying from testicular cancer
2. reduces the risk of non-cancerous prostate disorders
3. reduces the risk of perianal fistulas
4. may possibly reduce the risk of diabetes (data inconclusive)

Negative for male neutering

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

Positive for spaying females

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

Negative for spaying females

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

This research is further to that in my previous blog To Spay/Neuter or not to Spay/Neuter issued in May http://caninehealth101.blogspot.com/2011/05/to-spayneuter-or-not-to-spayneuter.html


http://www.naiaonline.org/pdfs/longtermhealtheffectsofspayneuterindogs.pdf