08/28/2025
In the last ten years spaying and castration (neuter refers to either s*x) have gotten more attention than in the previous 31 years of my career. Recent studies done in California have suggested that early neutering has a negative influence in musculoskeletal development and even cancer. Although I have not accumulated data to prove any particular claims, I do make the following observations.
Spaying and castration in my first decade of practice (the eighties) was done later than now, typically at 1 1/2 years of age. The factor determining the age back then had more to do with the safe use of anesthetics. The anesthetics we have now are so good, anesthetizing patients down to three months of age is unremarkable. Also in the eighties the number of people choosing not to neuter was much higher. The result: I would see five cases of breast cancer (benign and malignant) every month. Now, with younger neutering, I see less than ten cases of breast cancer in a year, and those cases 90% of the time are in unspayed dogs. I do not believe I am seeing more developmental problems compared to back then. I am sensitive to the concerns, and I have moved back my recommendation for the age to neuter from 6 months of age to 8 months. Another source of information comes from Banfield Veterinary Hospitals. They are the largest corporate group of practices in the country. Although, I have not been a big fan of corporate practices, they are uniquely able to gather information from all their practices nationwide and have published statistics you may find interesting. The following quote about statistics Banfield has published I got from an AVMA article:
" Pets are living longer, according to the report. The mean life span of a cat in 2012 was 12 years, an increase of 10 percent since 2002. The mean life span of a dog in 2012 was 11 years, a 4 percent increase since 2002.
Neutered male cats live a mean of 62 percent longer than unneutered male cats, and spayed female cats live a mean of 39 percent longer than unspayed female cats, the report said. Neutered male dogs live a mean of 18 percent longer than unneutered male dogs, and spayed female dogs live a mean of 23 percent longer than unspayed female dogs.
Two of the five states with the shortest life span for dogs have the highest percentages of unneutered and unspayed dogs, Mississippi at 44 percent and Louisiana at 38 percent.
Here is a link to reports Banfield has published:
https://www.banfield.com/State-of-pet-health