Evidence Update: Evaluating the Benefits & Risks of Neutering in Dogs and Cats

In 2010, I published a narrative review of the literature evaluating the risks and benefits of neutering in dogs and cats. Much additional research has been completed and published since then, and I have just complete an update of my review. The new evidence has resulted in a number of changes to my conclusions and recommendations, so while I will leave the link to my previous review active, this update supersedes the older version.

Evaluating the Benefits & Risks of Neutering Dogs and Cats: 2014 Update


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8 Responses to Evidence Update: Evaluating the Benefits & Risks of Neutering in Dogs and Cats

  1. Sarah says:

    That was really interesting and informative. Thank you for such a well researched update.

  2. Elliott says:

    This is really helpful, thank you!

  3. Mason Small says:

    Thank you; as a lay person, I was grateful for the clarity, conciseness and broad scope of this article. For me the question is both the effect of spaying or neutering on disorder/disease, and overall quality of life/wellness/vitality, which is much more difficult to measure. I hope future studies will look more closely at aging issues, for instance the effects of neutering/spaying on arthritis/mobility (not just incidence of torn ligaments or hip dysplasia).
    Also, it seems veterinarians from Europe and Australia are less likely than North American veterinarians to advocate canine spay/neuter – is anything besides tradition/culture responsible for geographically different veterinary practices?

  4. skeptvet says:

    Yes, neutering is less routinely recommended in Europe than in the U.S. (not sure about Australia). I believe this is primarily a cultural and historical difference, with neither position very directly based on science. I agree, there is a lot of work to be done elucidating the complex and varied effects of neutering, and it is good that we are seeing more research and more open-minded discussion on the subject.

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  6. Theresa-Anne Mackintosh says:

    I have a question regarding when to spay in terms of the last heat and build up to the next. I prefer to allow a dog to mature first, perhaps one or two heats. That said, it’s a big responsibility to have an intact dog, even if you intend to spay/neuter later. My question pertains to when exactly is best before the next heat. How much is too close to the following expected heat? I know definitely not during a heat (complications/blood etc). Slap bang in the middle of two is advised, so you’re out of possible false pregnancies overhang if there were any such things. Can one spay too close to the next heat? I’m talking more from a behaviourist angle and hormones and how that correlates to physiology. Vets and behaviourists/trainers don’t always agree ;). Can you tell me, does it affect anything if you’re more in the estrogen build up or progesterone phase, I suppose in the middle tries to have those hormones (and the dog) on more of a plateau. A vet once told me, it doesn’t matter to them. Yes, not to spay too soon after a heat, if there was even slight teat swelling, not during a heat of course, but a month closer or further back does it affect what they do and more importantly will it have a specific outcome on your dog hormonally/behaviorally? What is your opinion? Some people say, probably old wives tales, but the dog could get ‘caught’ in their itchy and scratchy ‘bitchy’ phase as bitches can become touchy before a heat. Does it not matter? Hormones will subside and platea within a few months after a spay regardless.

  7. skeptvet says:

    I am not aware of any specific research looking at when in the heat cycle to spay and what, if any, difference that makes in terms of health or behavior. The general recommendation is to wait 30 days after the heat, to avoid a slightly higher risk of surgical complications when the uterus is larger and has a greater blood supply. Any time between then and the onset of the next heat should be equivalent since there aren’t any hormonal changes during the diestrus between heats. Since the onset of the next heat can be unpredictable, I would normally recommend having the surgery 1-2 months after the last heat you want her to have, though again that is just a pragmatic decision, not something based on specific research evidence.

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