“Spay and neuter”, they said. It’s good for their health, they said.

More troubling, despite the unambiguous statements made by proponents of the salutary effects of spay-neuter on dogs, a series of long-term research programs has begun to show that the effects are far more subtle — and sometimes outright damaging. Benjamin Hart, a researcher and veterinarian at the University of California, Davis, has led the biggest effort to date to see exactly what the repercussions of desexing might be, in the long term, using the database from his university’s veterinary hospital. By removing dogs’ reproductive organs, gonadectomies also remove their main source of hormones — estrogen, testosterone and progesterone — each of which has a role not just in reproduction, but systemically through the body.
 

The first publication by Dr. Hart and his team, in 2013, reported that desexing golden retrievers, especially before six months of age, increased their risk of serious joint diseases, four to five times over the risk intact dogs face. They have since found higher rate of joint diseases among desexed Labrador retrievers, German shepherds, Doberman pinschers, Bernese mountain dogs and St. Bernards. Risks of cancer increase multifold in spayed goldens, neutered boxers and all Bernese. Desexed dogs of all types suffer higher rates of obesity. One of the most touted claims of spay-neuter — that it increases an animal’s life span — may be tempered by the finding that with an increased life span comes an increase rate of life-taking cancers.
 
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Similarly, the oft-cited behavioral improvements of desexed dogs are questionable. Dr. Hart has reported that only one in four male dogs neutered for reasons of “aggression” shows less of the behavior after the surgery; the same holds for rates of mounting and excessive urine-marking. In females, there is even some evidence of an increase in aggressive behaviors if they are spayed before the age of 1.

The argument against routine spay-neuter is framed in animal rights blather, which is crocodile delicious. The same activist veterinarians who’ve enacted bans on “elective” animal husbandry procedures (like cat declawing and tail docking) apparently did so without considering that these surgeries keeping their clinic lights on are also “elective”.