Pet sterilization is controversial, almost as much as the debate on nutrition. There is the debate on trap-neuter-release (TNR) in cats. There is the no-kill controversy and the need for low-cost sterilization. All are minefields for stating your opinion. However, the newest one is the wisdom and methodology of the emerging canine neuter conundrum.

First, I’ll give you a bit of history. When I began practicing (yes, over 30 years ago), I was told to believe in the age-old recommendation of sterilization at six months of age. The reasons seemed obvious.

First, it was anesthetic safety. The anesthetics of old were hard on young animals. The best example was methoxyflourane. It took a long time for pets to purge this anesthetic out of their systems. They were stumbling for days. Thankfully, new drugs have replaced these old medications and we can do surgery on tiny, young tykes and they can wake up very fast.

Though this put a minimum age on the puppies and kittens for safety reasons, there was also an upper limit. We wanted them spayed before they reached time to come into heat. The six-month rule worked well and only the rare one (usually cats) would get into breeding mode before this time.

The concept of getting them before the heat cycle had a medical advantage. The mammary glands of female dogs that went through a heat swelled and developed, putting them at risk of mammary cancer later in life.

With all this, we thought we had it right. But, then the concept of early sterilization crept in. Shelters want to adopt out animals that cannot contribute to the population. This meant sterilizing them when they were 8 weeks old, sometimes less. This pediatric sterilization has been practiced for the last decade or so. Breeders also do it when they want to send their puppies to new homes with no possibility that they can be bred by the purchaser.

So, we seemed to be settled into this mode as veterinarians, but a new wrinkle crept in. One study showed that bone cancer was more common in Rottweilers that were spayed versus those that were left intact (or spayed later in life). What? Sterilization could have a negative effect? This had to be examined.

We already knew that spaying females tended, in a small percentage, to trigger urine incontinence issues later in life. Sterilization also boosts rates of obesity because the metabolism slows and the dog’s focus moves from “Where is my mate?” to “Where’s dinner?”

But, a recent study shows that we can see higher rates of cruciate ligament disease, hip dysplasia, and certain cancers in early-sterilized dogs.

Interestingly, the European status quo is to NOT have your dog sterilized. Could it be they are ahead of the game and have it right?

On our side of the pond, veterinarians and welfare groups have been vehemently telling people that sterilization is the way to go. In fact, jurisdictions reward sterilization with lower licensing fees. Some places don’t allow unsterilized dogs unless they are part of a breeding program.

However, new evidence is making veterinarians open their minds to a new paradigm. We’ve also seen client requests for later sterilization. It will take a while before we can determine what is best for pets, and the debate continues. And, old habits die hard.

Following is the first paper on the “dangers” of early sterilization, followed by a rebuttal on this paper.  And you may also check out the newest research on the pitfalls of sterilization.

Dr. Louise Janes D.V.M. & Dr. Jeff Grognet D.V.M

Mid-Isle
Veterinary Hospital
5-161 Fern Road
West Qualicum Beach, BC
Tel (250) 752-8969

See all articles by Dr. Louise Janes D.V.M. & Dr. Jeff Grognet D.V.M.