Studying the Study

Photo by Kevin Lowery | www.kevinlowery.com

Photo by Kevin Lowery | www.kevinlowery.com

The shocking result of a study on the effects of early neutering in Golden Retrievers was recently released in the online journal Plos One.  Goldens neutered early, before one year of age, were judged more likely to develop hip dysplasia, cruciate ligament tears, and some forms of cancer than those dogs left intact or neutered after a year of age.  Golden lovers began calling and emailing me with questions and concerns as soon as the popular press picked up the story.

Most of the dogs we teach at Canine Assistants are Goldens.  Maybe that’s why people wanted to know my take on the study.  Perhaps I was an easy way to access the opinion of my veterinarian husband, Kent Bruner, whose practice at Canine Assistants consists primarily of Goldens.  Regardless of the reason, I was enthusiastic to review the findings of this research…until, that is, I actually studied the study.

The researchers obtained data on nearly 800 Goldens Retrievers, an enormous number for this type of project.  It is extremely rare to see a study on dogs as a species, let alone on a single breed, with such a large sample size.  But, while the amount of data collected is impressive, the source of the data concerns me deeply.  The dogs were all patients at the Veterinary Medical Hospital, University of California, Davis.

UC Davis is a fantastic veterinary teaching hospital, offering cutting edge care for those breeders and pet parents who want the very best for their animals.  It’s the type of place you turn when your beloved dog needs specialized treatment for major problems such as hip dysplasia, cruciate ligament tears, cancer, and infertility.  All the data collected came from a very small population of dogs---those seen at UC Davis.  That one fact makes any conclusions drawn from the data suspect.

Consider the finding that Goldens neutered before one year of age are more likely to develop hip dysplasia or have cruciate ligament tears than those left intact or neutered after a year of age.  At a vet school, most of the intact dogs seen belong to breeders who have retained those specific animals for breeding, at least in part, because they have good hips and conformation that makes cruciate ligament tears less likely.  It makes sense then that few of the intact Goldens seen at a vet school would have hip dysplasia or cruciate ligament tears.  At the same time, those pet guardians who would take their dogs to a vet school for treatment of hip dysplasia or ligament tears most likely neutered their pets early as part of their commitment to responsible care.

Likewise, committed pet guardians, those who usually neuter early, are the individuals most likely to take their dogs to a veterinary school or specialty center for cancer treatment.  Good breeders, especially Golden breeders, are very committed to breeding only dogs whose bloodline shows no evidence of early cancers.  So, much like with orthopedic issues, the dogs most likely to be seen at a veterinary teaching hospital with cancer are those belonging to guardians who probably, responsibly, neutered them early.

So are the findings of this study valid in any way?  I have absolutely no idea.  There isn’t any way to know for certain unless the same large amount of data can be collected from sources less likely to produce skew the results---meaning a cross-section of all Goldens not just those taken to specialty hospitals.  Previous studies with smaller sample sizes have reported inconsistent results.  So, for now at least, my pet dogs will continue to be spayed or neutered before one-year of age.

PS-Below is a link to the article for those of you who want to read it.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0055937


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Positively Expert: Jennifer Arnold

Jennifer is the CEO and founder of Canine Assistants, a non-profit organization that trains and provides service dogs for children and adults with physical disabilities or other special needs. She has written two best-selling books, "In a Dog's Heart" and "Through a Dog's Eyes," and appeared in a PBS special about Canine Assistants.


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9 thoughts on “Studying the Study

  1. Jan

    Thanks for posting this response, Victoria! It is very well thought out and certainly points out the potential problems with the study's findings.

  2. Tegan

    While I agree with your criticisms, the conclusions of this research are in keeping with other research on the effects of desexing (especially early age desexing). That is, the fact that early desexing was associated with increased rates of hip dysplasia and cranial cruciate ligament tears, and cancer, is not new, and can be seen in results from many other research projects.

    What I am saying is: Though there are problems in this research design, the conclusions made aren't different to other studies with different research designs.

  3. Pingback: Golden Retrievers: Cancer If You Do, Cancer If You Don’t | Some Thoughts About Dogs

  4. doodle owner

    The validity of the study lies in the fact that it is a cross-section. The dogs were all seen at UC Davis vet school, but did not originate there. So, they do, in fact represent a cross-section of the population. As a scientist, I recognize that studies like the ones at UC Davis are only a first approximation. The findings are statistically significant and there are many variable to be explored in a larger, more stratified type of study in the future. The UC Davis study provides the necessary background information to justify such a study. Whether or not ESN is related to hip dysplasia is still an open question. However the UC Davis throws down the gauntlet and begs for further investigation into this issue.

  5. Linda Wunschel

    So, I'm confused as to neuter my golden female early, late, or not at all. I especially dread the increased risk of hemangio and mct's in late neutered females. Hemangiosarcoma is a horrible cancer. Would it be best to neuter early to try to avoid this type as well as mast cell (had a female die from MCT)? I don't know what to do. My puppy is from an excellent holistic-type breeder with longevity in the line.

  6. Golden owner

    My vet feels that the best for my female golden is to leave her intact. I do worry about the pyometra and mammary tumors but did read in one source that Mammary rumors aren't common in goldens. Maybe that was why they weren't included in this study?

  7. Jennipher Cunningham

    I am quoted this study almost daily, by owners at a loss over their male dogs behaviors. Most people have no idea how to handle a intact pubescent dog yet they hear about this study and opt to wait to get their dog neutered. I have even had people instructed by their breeders to wait. But really I have to wonder how many people are really equipped and ready to handle canine puberty??!
    My issue with this study, well I have many really, but mostly it is all the external inconsistancies in it. What are all these dogs eating, what is their exersize level, what blood lines are these dogs from??? Is all of this a example of a breed group 'passing the buck' on these health issues? But more importantly, after generations of work to get people altering their pets we are now back sliding and I am seeing more and more intact dogs with overwhelmed owners who are waiting for some magic age to get it done. And in the meantime their dog is going into heat cycles ( which is WELL documented in increasing mammary tumor risks!) or their male dog is now a leg lifting barking machine. My background is animal shelter/ vet tech and dog training and I just have to think of all the unplanned and accidental litters that HAVE to be happening due to this misinformation.
    And shelters is where I point to - I worked at a large on here in Denver for years and we neutered puppies at 5 pounds and up. If these increases were true in hip dysplasia and such wouldn't shelter dogs be rife with it all??????

  8. boxofivehands

    I disagree with early spay/neutering. As with humans, hormones play a vital part of not only growth and development in the body, but also keeping things balanced within the systems. Unless you have an overly aggressive or excitable male or one who is prone to wandering, keep your animals intact as long as possible. It's really not a big deal cleaning up after a female in heat. AND BE A RESPONSIBLE PET OWNER!

  9. C Clarke

    I
    am currently training a golden retriever for diabetic alert service dog and he
    is now one year old and has not been neutered yet. He will be soon. My friend
    has a golden of the same age as a pet and was neutered at 3 months old and he
    has already had torn cruciate and Achilles tear that she saw happen in her back
    yard when he was playing with a tennis ball. He has had surgery (very
    expensive) for this leg injury and mended well. He is a swimmer in their pool
    and gets lots of exercise to strengthen him but at 11 months old this major
    injury to his leg was not due to unusual twist or strain or maneuver in any
    unusual way. So I am inclined to think why risk the chance if waiting till the
    dog is 13 months causes no harm. He will not father any pups as he is under
    strict supervision in my care. He will be neutered soon so when he goes to his
    diabetic owners he will be fixed and more than a year old.

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