Spay and Neuter: When and If ever?

[megansmomma]

Dr. Becker. More Misleading and Unethical Advertising for Alternative Veterinary Medicine | The SkeptVet
I’ve written before about the unethical and misleading negative advertising that so often characterizes the promotion of alternative veterinary medicine. But I ran across another example that set my teeth on edge and illustrated a particular problem I have with this kind of thing.

Dr. Karen Becker, a prominent CAVM vet who writes for one of the most notorious sites promoting quackery through denigrating conventional medicine, Mercola.com, recently blogged about the much-reported decline in veterinary office visits. In this article, she makes a number of assumptions for which there is little or no evidence, and several accusations about the inadequacy of conventional veterinary care.

The accusations essentially amount to saying that conventional medicine ignores preventative care apart from given vaccinations and selling pest-control products, both of which Dr. Becker frequently cites as significant health hazards for our pets.

Perhaps a reason for fewer vet visits is the new canine vaccination guidelines which will hopefully put an end to the dangerous and unnecessary practice of yearly re-vaccinations.

I suspect another reason (aside from today’s tough economic climate), is because many traditionally trained DVMs practice ‘reactive’ veterinary medicine.

This means they don’t have much to offer pets unless and until they’re good and sick…

…preventive medical care in the mainstream veterinary community has evolved to mean not much more than yearly vaccines and chemicals to discourage pests and parasites like fleas, ticks and heartworm.

There is rarely discussion between vets and pet owners about nutrition (because vet students receive almost no education in the subject), exercise and other physical therapies, or the importance of a strong, resilient and balanced immune system.

This also raises the cliché about conventional veterinarians being ignorant in the area of nutrition, which is nonsense. The definition of ignorance most likely meant here, is simply a failure to agree with specific theories about what constitutes a healthy diet, including the unsubstantiated beliefs often promoted about the benefits of raw diets, the dangers of grains, and so on.

This then leads to the suggestion that alternative veterinarians do a better job of preventative care, because they promote “wellness” therapies.

For some reason the methods used to maintain a pet’s vibrant good health – everything from species-appropriate nutrition to maintenance chiropractic care to homeopathic remedies and herbal supplements – fall into the category of ‘alternative medicine.’

Isn’t it strange that natural modalities used not to cure illness (although they do that, too), but to maintain health are thought of as ‘alternative,’ yet chemical drugs and invasive surgery are considered mainstream health care?

Actually, it isn’t strange at all. There is no reliable scientific evidence for the preventative health benefits of maintenance chiropractic care, homeopathic remedies or herbal supplements. These products are touted as “wellness” care based solely on the personal beliefs of the vets who use them and the beliefs of previous generations of vets and animal owners. This is the same level of evidence that has supported such winning strategies as bloodletting, purging, and animal sacrifice as preventative health measures.

What is strange is that someone with medical training can so blithely denigrate preventative and therapeutic methods proven to work and wonder at the failure of mainstream medicine to accept without proof her belief that these alternative therapies are better.

I recommend twice yearly wellness examinations to my Natural Pet clients.

A thorough nose-to-tail professional checkup every six months is the best way for you and your vet to detect and stay on top of any changes in your pet’s health. This is especially true for older pets.

This is undoubtedly great for the bottom line, but again there is no evidence that biannual or annual wellness examinations recommended for all pets is an effective or efficient strategy for preventing disease or extending length and quality of life. In humans, the evidence in fact is building against the value of annual exams for well people. There is no evidence either way in veterinary medicine, so while I myself think it likely that regular examinations could have some benefit, there is no objective reason for a strong recommendation of this kind. And certainly such visits are not a substitute for the “chemical drugs” and vaccinations that have been far more effective than any other measure and reducing disease and preserving health in our companion animals.

…Proactive vets are typically obsessive about clinical pathology…most proactive vets recommend annual vector borne disease testing instead of waiting until lyme disease has set in, causing incurable auto-immune polyarthritis.
This is a completely irrational and baseless recommendation. Screening tests without an appropriate reason for doing them waste money and cause far more harm than they prevent. There is a strong movement in human medicine now to reduce exactly this kind of misguided thinking. So to imply that the care such alternative vets provide is superior to that of conventional veterinarians because the former recommend unproven preventative measures and unnecessary testing is misleading and unethical. Given the complaints so often made by CAM vets about the purported financial motivation behind many mainstream practices, it is quite ironic that this sort of advertising promotes far more aggressive, and likely expensive, use of approaches with no proven value.

[pstinard]

Originally Posted by megansmomma

This We Don't Have a Cure for Cancer Yet - or Do We?

Yikes!!! Mercola is definitely a piece of work. The viszlas study that he posted on his website isn't necessarily a bad study, since it WAS peer-reviewed and published in a prestigious journal. But he is putting it on his website to make a point, and I also have to wonder how he obtained the copyright to post the entire PDF file.

[pstinard]

Here is a table from the article "Pros, Cons, and Techniques of Pediatric Neutering," by Margaret V. Root Kustritz. (Vet Clin Small Anim 44 (2014) 221–233). It assigns a numerical score to the pros and cons of neutering, based on ratings by veterinarians. Here is the description of the table from the article:

"One study asked veterinarians to rate morbidity and mortality of various disorders and multiplied this value by incidence to create an impact score, to help guide veterinarians as they educate clients or make decisions for stray animals in shelters (Table 2)."

[pstinard]

Originally Posted by pstinard

Here is a table from the article "Pros, Cons, and Techniques of Pediatric Neutering," by Margaret V. Root Kustritz. (Vet Clin Small Anim 44 (2014) 221–233). It assigns a numerical score to the pros and cons of neutering, based on ratings by veterinarians. Here is the description of the table from the article:

"One study asked veterinarians to rate morbidity and mortality of various disorders and multiplied this value by incidence to create an impact score, to help guide veterinarians as they educate clients or make decisions for stray animals in shelters (Table 2)."

From this table, the biggest pro's are reduction of pyometra (score of +100) and mammary neoplasias (breast cancer; +24). The biggest cons are urinary incontinence (-66), surgical complications (-20), obesity (-14), and CCL rupture (-11). Surprisingly, the biggest negative effect was the chance of urinary incontinence. Based on the numerical scores, overall, the pro's outweigh the cons. Note that this table is for female dogs overall, and is not broken down by size or breed.

[gemy]

Originally Posted by pstinard

AHA!!!! The systematic review mentioned in the Viszlas study stating that risk of mammary cancer shouldn't be a concern in making decisions about spaying is the same review mentioned in the study that I just quoted in my last post:

"A recent attempt to determine the significance of these data by systematic review of the veterinary literature was unable to identify strong evidence suggesting that spaying decreases the risk of mammary cancer; however, this systematic review is based on work in human medicine and requires a massive body of literature, which does not exist in veterinary medicine.35"

So there is a difference of opinion on the validity of that systematic review...

AHA indeed. You really need to look very closely at the wordage, and how it was swung in the Vizslas report and the above quote. I am not sure why your authors quote above was even looking at human research. Other than perhaps a review of the literature required IDK 10,000 studies which quite simply don't exist in vet medicine, which I would think is probably true But still in one way your quote is saying, there is not enough evidence because there is Not enough evidence to say one way or another if there was strong evidence to support mammary tumours.

That is different to the Vizslas report stating that another author said the evidence was "weak and not a sound basis...et" There is a strong indication that report is referencing the author above. And if so, they have mis-represented their statement in my mind. The fact that they were unable to develop strong evidence because there was simply not enough body of evidence available, is not the same thing as saying there is weak evidence. The might we can't take a position either way for strong or weak evidence, as sic there is not enough evidence to make a decision on this.

So to my mind the question is, given that dog population is a whole lot less than human population, with I would think a narrower gene pool, how much is massive for dog research? I mean how many studies, etc etc.

[pstinard]

Originally Posted by pstinard

From this table, the biggest pro's are reduction of pyometra (score of +100) and mammary neoplasias (breast cancer; +24). The biggest cons are urinary incontinence (-66), surgical complications (-20), obesity (-14), and CCL rupture (-11). Surprisingly, the biggest negative effect was the chance of urinary incontinence. Based on the numerical scores, overall, the pro's outweigh the cons. Note that this table is for female dogs overall, and is not broken down by size or breed.

I forgot to mention that the pro's for neutering male dogs greatly outweigh the cons, the biggest pro being the reduction of benign prostatic hypertrophy (+368).

[pstinard]

Originally Posted by gemy

AHA indeed. You really need to look very closely at the wordage, and how it was swung in the Vizslas report and the above quote. I am not sure why your authors quote above was even looking at human research. Other than perhaps a review of the literature required IDK 10,000 studies which quite simply don't exist in vet medicine, which I would think is probably true But still in one way your quote is saying, there is not enough evidence because there is Not enough evidence to say one way or another if there was strong evidence to support mammary tumours.

That is different to the Vizslas report stating that another author said the evidence was "weak and not a sound basis...et" There is a strong indication that report is referencing the author above. And if so, they have mis-represented their statement in my mind. The fact that they were unable to develop strong evidence because there was simply not enough body of evidence available, is not the same thing as saying there is weak evidence. The might we can't take a position either way for strong or weak evidence, as sic there is not enough evidence to make a decision on this.

So to my mind the question is, given that dog population is a whole lot less than human population, with I would think a narrower gene pool, how much is massive for dog research? I mean how many studies, etc etc.

Systematic review articles are notoriously biased, since they rely upon the authors to pick and choose which articles they think are relevant. The best thing to do is to read as many primary research articles as possible, look at their materials and methods, and decide which ones are the best quality. The scientific consensus is that spaying reduces the rate of mammary cancer, so I'm surprised at the viszlas conclusions, but again, it may be a breed-specific effect.

[megansmomma]

Benefits & Risks of Neutering, an Evidence Update–Cancer and Behavioral Problems in Vizslas
Posted on February 11, 2014 by skeptvet
As part of my ongoing coverage of the risks and benefits associated with neutering, I wanted to review a recent article on the subject, this one looking specifically at cancer risk and behavioral problems in Vizslas.
Zink, MC. Farhoodly, P. Elser, SE. Ruffini, LD. Gibbons, TA. Riegr, RH. Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas. J. Amer Vet Med Assoc. 2014;244(3):309-319.
The Study

This study involved *an analysis of data collected in 2008 through an online survey of owners of Vizslas in the U.S. and other countries (U.S. owners made up about 87% of the responses, with almost all the others coming from the UK, Australia, and Canada). Information was collected on about 2,500 dogs, and both cancer and behavioral problems were reported in about 25% of these.
The authors looked at the cancers and behavioral problems reported by owners as well as the age when individuals were neutered, if they were, the sex, and the age at which the medical problems examined were reported (though this last figure often had to be guessed at). The authors specifically excluded many conditions from the analysis, including some previously reported to be associated with neuter status. They did not, for example, consider orthopedic diseases because these were uncommon (~9% of the dogs). Oddly, they did not consider skin conditions either, though these were reported in about 20% of the dogs.
The reported results cover several cancers that are especially common in Vizslas, including Mast Cell Tumors (MCT), Hemangiosarcoma (HAS), and Lymphoma (LSA), as well as behavioral problems (noise phobias, separation anxiety, and various forms of aggression). The general results, broken down by age of neutering, are reported in the tables below.
The odds of MCT and LSA were higher for neutered than intact animals. The odds of HSA was higher for neutered females than for intact females, but there was no relationship between neutering and HSA risk for males. The odds of cancers other than these three were also higher for neutered than for intact animals. For all of these cancers, the odds were higher in those neutered after 12 months of age than in those neutered earlier.
For behavioral problems evaluated, the odds of having such a problem were higher in dogs neutered before 6 months of age than in intact dogs. There were no differences in the odds of behavior problems between intact dogs and those neutered after 6 months of age with the exception of storm phobia which was more common in neutered animals overall than in intact animals.
There was no difference in the age at death or the longevity of neutered dogs compared with intact dogs.
Limitations of the Study

The first potential limitation of this study is that the population of dogs included are potentially not representative of the general pet dog population. Only one breed was included, and only 60% were reportedly kept as “primarily a family pet,” with most of the others being used for show or hunting activities. About 23% were reported to have had offspring and almost half (43%) of the dogs were intact, whereas surveys suggest over 80% of the overall owned dog population is neutered. The average age at death was also reported to be 9 years, which seems quite young compared to many other breeds and mixed-breed dogs of similar size. Since there are genetic factors involved in many health conditions, and potentially developmental and environmental factors associated with how dogs are kept, caution must be used in extrapolating results from one population to another.
Another significant limitation of this study is the method of data collection. All data was collected by anonymous online questionnaire, with no attempt to verify the accuracy or validity of these data. Diagnoses of cancer and behavioral problems and assessment of age at neutering were based entirely on reports of owners, sometimes many years after the fact.
This raises a host of concerns. Owners may have reported diagnoses incorrectly, such as misidentifying cancers or reporting benign tumors as “cancer.” Owners may have been more likely to report cancer and/or neutering information if they believed there to be a relationship between the two or if they knew one purpose of the study was to examine such a relationship. Owners also identified cancer and skin conditions as top health concerns, suggesting a population of respondents particularly interested in these conditions, which might have affected their rate of reporting them.
There is also no way to identify what if any differences there were between people who participated in the survey and people who did not, or between the dogs owned by these different groups. It is likely that people who were aware of the survey and motivated to complete it differed in numerous ways from other Vizsla owners and owners of other kinds of dogs, and this again could affect the health conditions reported and the risk factors affecting them.
Another issue is that this study looked at potential risks posed by neutering, but it did not include assessment of most of the potential benefits of this procedure in this population. For females, for ecample, neutering is believed to be protective against mammary cancer (though the evidence is not as strong as commonly supposed), which in some populations is a very common and frequently malignant type of cancer. In this population, mammary cancer was reported in less than 1% of the females in the study, a rate dramatically less than in other populations studied. This suggests either that this population is a much lower risk of mammary cancer than others, in which case the protective effect of neutering might not be meaningful, or that the incidence of this disease was underreported.
Similarly, uterine infections (pyometra) are a common and serious disease in intact females, and these can be completely prevented by neutering. Yet the rate reported in this study was quite low. 22 cases were reported, which would be a rate of about 4% of the ~535 intact females included. Other studies have reported rates of 10-50% depending on age, so either this population has an unusually low rate of this disease, or the incidence was not accurately reported.
Health problems and cost or disruption for owners associated with estrus, reproductive behaviors, or actual reproduction were also not evaluated in this study.
Overall, the study found no difference in the longevity or overall mortality of neutered versus intact dogs. This is in contrast to other studies which suggest neutered animals may live longer on average than intact animals. More importantly, it calls into question the significance of the reported increase in cancer risk in neutered dogs. If neutered dogs are truly at significantly higher risk of often fatal diseases like HAS and LSA, one might expect intact animals to live longer as a results of being less likely to experience these diseases. And if the two groups have roughly the same life expectancy, perhaps there are benefits to neutering not reported here that counterbalance the risks discussed?
Bottom Line
This study contributes useful new information to the ongoing process of evaluating the risks and benefits of neutering. It supports information from other studies, in Rottweilers and Golden Retrievers, that suggest neutering may increase the risk of some cancers, such as hemangiosarcoma and lymphosarcoma, in breeds predisposed to develop these diseases.
The study also has a number of significant limitations. The dogs in the study were all of one breed, and they differed in a number of ways from the general pet dog population, so findings in this group may not be applicable to other populations. *The data was collected though anonymous questionnaires completed by owners, often years after the events being asked about, and there was no way to confirm the accuracy or validity of these reports. There is also a high risk that the people who chose to participate in the survey, and the dogs they own, are quite different from the general pet owning population and their pets, in their concerns, knowledge, and pet care practices.
The study did not examine many of the risks posed by being intact, which have to be considered in weighing the overall risks and benefits of neutering. Rates of pyometra and mammary cancer, common and serious medical problems prevented by neutering females, were far lower in this study than generally reported elsewhere, suggesting either that the study population was quite different from other dog populations or that the rates of these diseases were not accurately reported.
And it is unclear how significant the reported increase in the risk of cancers in neutered animals really is since there was no overall difference in the longevity of neutered and intact animals. If neutered animals are much more likely to get cancer, it is surprising that they tended on average to live just as long as intact dogs.
Overall, this study supports the current trend towards questioning the dogma of routine neutering for all dogs. The risks and benefits are likely to vary according to breed, age, and many other variables, and a one-size-fits-all approach is not ideal. Unfortunately, a great deal of additional research will need to be done for dog owners and veterinarians to have confidence in specific recommendations for individual dogs.

Benefits & Risks of Neutering, an Evidence Update–Cancer and Behavioral Problems in Vizslas | The SkeptVet

[megansmomma]

Benefits and Risks of Neutering, an Evidence Update: Study Investigates Effects of Neutering in Golden Retreivers
Posted on February 17, 2013 by skeptvet
Given that I recently presented a couple of evidence-updates on the subject the health effects of neutering, the timing was excellent for the release last week of a new research study looking at the same issue.

Torres de la Riva G, Hart BL, Farver TB, Oberbauer AM, Messam LLM, et al. (2013) Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers. PLoS ONE 8(2): e55937. doi:10.1371/journal.pone.0055937

This was a retrospective cohort study in which records were searched to identify Golden Retrievers who had been patients at the UC Davis veterinary school, were between 12 months and 8 years of age, and who could be classified as having been neutered “early” (before 12 months of age), “late” (after 12 months of age), or not at all. The occurrence of a number of diseases common in Golden Retrievers was then evaluated to see if it differed between dogs in these three categories. There are several reasons to be cautious in how we interpret the results of this study, but let’s start by looking at what those results were.

The authors looked at the occurrence of hip dysplasia (HD), elbow dysplasia (ED), cranial cruciate ligament rupture (CCL), and a number of cancers com including lymphosarcoma (LSA), hemangiosarcoma (HSA), mast cell tumor (MCT), osteosarcoma (OSA) and mammary cancer (MC). The figures below illustrate the relative occurrence of some of these diseases in males and females by neuter status (the diseases not shown did not occur often enough to be included in the analyses).

For CCL the difference between intact and early-neutered was statistically significant (K-M). For HSA, the differences between early and late-neutered and intact and late-neutered groups were statistically significant (RR), as were differences for MCT between early and late-neutered groups. A similar statistical comparison for late neutering and intact groups was not possible for MCT because there were 0 cases in the intact group.

These results suggest that there is a complex and inconsistent pattern of associations between neuter status and these diseases. In general, there was a tendency for neutered animals to have higher rates of these diseases than intact animals and for early neutered animals to have higher rates than late neutered animals. However, there are many cases in which differences were not statistically significant or the difference was significant in one sex but not the other, and a few in which the direction of the difference was opposite that expected (for example with HAS occurring more often in late-neutered females than either intact or early neutered females).

The difficulty lies in knowing what these results mean in terms of predicting the risks for individual pets and making decisions about neutering in general. The natural tendency will be to look at these data and conclude that not neutering, or neutering after 12 months of age, is safer than the common current practice of neutering most animals before 12 months. However, this is not a conclusion we can reliably draw from these data.

To begin with, this is a group of dogs that are, in many ways, very different from most dogs neutered by veterinarians. Apart from only representing one breed, and a breed known to have higher rates of the diseases studied than most other breeds, the subjects were patients at a university veterinary hospital. In general, only the sickest animals with the most unusual or serious diseases are seen at universities. Most healthy animals or those with typical illness are seen at general veterinary practices. So it is uncertain if neutering will have the same effects as in this study on dogs of other breeds or those healthy enough to have never seen the inside of a university hospital.

The population also contained small numbers of intact and “late” neutered dogs. This makes it more likely that small, random differences in the health of individual dogs in the study group could alter the apparent effects of neutering on health. And the authors chose to limit the study population to dogs between 12 months and 8 years of age. Quite a few Golden Retrievers live past 8 years, and the rates of cancer generally go up dramatically with age. If the proportion of these diseases among intact and neutered animals over 8 years old are at all different from those in dogs under 8, then the direction and statistical significance of the differences between groups seen in this study could easily be altered.

And it’s important to consider the absolute risk and benefit numbers when making decisions about whether to neuter. If, in fact, neutering is strongly protective against a common cancer (as it is thought to be for mammary cancer) but also slightly increases the risk of a rare cancer, it may still make sense to neuter early depending on the unique situation of an individual patient.

Finally, two of the major diseases against which neutering is thought to be protective in females, uterine infection and mammary cancer, did not occur often enough to be included in the analysis. This may be because relatively few of the dogs were intact or because of the age cutoff. Obviously, if there really is a protective effect of neutering on these diseases that didn’t show up in this study, that might influence the interpretation of the results.

Overall, this is a useful piece of research adding to the information we have about the pros and cons of neutering and the possible role of age in the effect of neutering on disease. It should be over-interpreted as the final word by itself, but it should be incorporated into a broad analysis of all the available evidence.

As it stands, there is reason to believe early neutering has significant benefits in females, though as the recent systematic reviews pointed out the evidence behind this belief is not strong. There is also reason to be concerned about possible risks, though the evidence for this is also not robust yet. On balance, one can make a reasonable case on both sides, and the risk profile for individual dogs, as well as larger issues such as the problems associated with unwanted reproduction. Anyone who says there is an absolute and universal right answer concerning if and when to neuter female dogs is exaggerating by quite a bit.

For males, I believe the evidence of benefits from neutering, especially before 12 months of age, is not compelling, and I don’t see a strong reason to neuter earlier in the case of owned dogs with owners willing to commit to preventing roaming and unwanted reproduction and in the absence of intolerable interdog aggression. For large breeds in particular, delaying neutering of males seems reasonable, though we very much need better evidence to have confidence in such a recommendation. It is encouraging that more attention is now being paid to the complexities of neutering and the risks and benefits associated with it, and I am optimistic that this will lead us to more reliable guidelines in the future.


Benefits and Risks of Neutering, an Evidence Update: Study Investigates Effects of Neutering in Golden Retreivers | The SkeptVet

[megansmomma]

Originally Posted by pstinard

Systematic review articles are notoriously biased, since they rely upon the authors to pick and choose which articles they think are relevant. The best thing to do is to read as many primary research articles as possible, look at their materials and methods, and decide which ones are the best quality. The scientific consensus is that spaying reduces the rate of mammary cancer, so I'm surprised at the viszlas conclusions, but again, it may be a breed-specific effect.

The 2 posts about are pretty much what I have said in the past, as laypeople we cannot run with information from these studies for the simple reason that we are not vets. If you take the time to read each of my posts you can see there are issues with the data, the statistics and even who was used for their research. It's very obvious to me that you cannot just take these studies and use a broad sweeping brush to include every animal into the conclusions of these studies.

[pstinard]

Originally Posted by megansmomma

Benefits & Risks of Neutering, an Evidence Update–Cancer and Behavioral Problems in Vizslas
Posted on February 11, 2014 by skeptvet
The reported results cover several cancers that are especially common in Vizslas, including Mast Cell Tumors (MCT), Hemangiosarcoma (HAS), and Lymphoma (LSA), as well as behavioral problems (noise phobias, separation anxiety, and various forms of aggression). The general results, broken down by age of neutering, are reported in the tables below.
The odds of MCT and LSA were higher for neutered than intact animals. The odds of HSA was higher for neutered females than for intact females, but there was no relationship between neutering and HSA risk for males. The odds of cancers other than these three were also higher for neutered than for intact animals. For all of these cancers, the odds were higher in those neutered after 12 months of age than in those neutered earlier.
For behavioral problems evaluated, the odds of having such a problem were higher in dogs neutered before 6 months of age than in intact dogs. There were no differences in the odds of behavior problems between intact dogs and those neutered after 6 months of age with the exception of storm phobia which was more common in neutered animals overall than in intact animals.
There was no difference in the age at death or the longevity of neutered dogs compared with intact dogs.
Limitations of the Study

The first potential limitation of this study is that the population of dogs included are potentially not representative of the general pet dog population. Only one breed was included, and only 60% were reportedly kept as “primarily a family pet,” with most of the others being used for show or hunting activities. About 23% were reported to have had offspring and almost half (43%) of the dogs were intact, whereas surveys suggest over 80% of the overall owned dog population is neutered. The average age at death was also reported to be 9 years, which seems quite young compared to many other breeds and mixed-breed dogs of similar size. Since there are genetic factors involved in many health conditions, and potentially developmental and environmental factors associated with how dogs are kept, caution must be used in extrapolating results from one population to another.
Another significant limitation of this study is the method of data collection. All data was collected by anonymous online questionnaire, with no attempt to verify the accuracy or validity of these data. Diagnoses of cancer and behavioral problems and assessment of age at neutering were based entirely on reports of owners, sometimes many years after the fact.
This raises a host of concerns. Owners may have reported diagnoses incorrectly, such as misidentifying cancers or reporting benign tumors as “cancer.” Owners may have been more likely to report cancer and/or neutering information if they believed there to be a relationship between the two or if they knew one purpose of the study was to examine such a relationship. Owners also identified cancer and skin conditions as top health concerns, suggesting a population of respondents particularly interested in these conditions, which might have affected their rate of reporting them.
There is also no way to identify what if any differences there were between people who participated in the survey and people who did not, or between the dogs owned by these different groups. It is likely that people who were aware of the survey and motivated to complete it differed in numerous ways from other Vizsla owners and owners of other kinds of dogs, and this again could affect the health conditions reported and the risk factors affecting them.
Another issue is that this study looked at potential risks posed by neutering, but it did not include assessment of most of the potential benefits of this procedure in this population. For females, for ecample, neutering is believed to be protective against mammary cancer (though the evidence is not as strong as commonly supposed), which in some populations is a very common and frequently malignant type of cancer. In this population, mammary cancer was reported in less than 1% of the females in the study, a rate dramatically less than in other populations studied. This suggests either that this population is a much lower risk of mammary cancer than others, in which case the protective effect of neutering might not be meaningful, or that the incidence of this disease was underreported.
Similarly, uterine infections (pyometra) are a common and serious disease in intact females, and these can be completely prevented by neutering. Yet the rate reported in this study was quite low. 22 cases were reported, which would be a rate of about 4% of the ~535 intact females included. Other studies have reported rates of 10-50% depending on age, so either this population has an unusually low rate of this disease, or the incidence was not accurately reported.
Health problems and cost or disruption for owners associated with estrus, reproductive behaviors, or actual reproduction were also not evaluated in this study.
Overall, the study found no difference in the longevity or overall mortality of neutered versus intact dogs. This is in contrast to other studies which suggest neutered animals may live longer on average than intact animals. More importantly, it calls into question the significance of the reported increase in cancer risk in neutered dogs. If neutered dogs are truly at significantly higher risk of often fatal diseases like HAS and LSA, one might expect intact animals to live longer as a results of being less likely to experience these diseases. And if the two groups have roughly the same life expectancy, perhaps there are benefits to neutering not reported here that counterbalance the risks discussed?
Bottom Line
This study contributes useful new information to the ongoing process of evaluating the risks and benefits of neutering. It supports information from other studies, in Rottweilers and Golden Retrievers, that suggest neutering may increase the risk of some cancers, such as hemangiosarcoma and lymphosarcoma, in breeds predisposed to develop these diseases.
The study also has a number of significant limitations. The dogs in the study were all of one breed, and they differed in a number of ways from the general pet dog population, so findings in this group may not be applicable to other populations. *The data was collected though anonymous questionnaires completed by owners, often years after the events being asked about, and there was no way to confirm the accuracy or validity of these reports. There is also a high risk that the people who chose to participate in the survey, and the dogs they own, are quite different from the general pet owning population and their pets, in their concerns, knowledge, and pet care practices.
The study did not examine many of the risks posed by being intact, which have to be considered in weighing the overall risks and benefits of neutering. Rates of pyometra and mammary cancer, common and serious medical problems prevented by neutering females, were far lower in this study than generally reported elsewhere, suggesting either that the study population was quite different from other dog populations or that the rates of these diseases were not accurately reported.
And it is unclear how significant the reported increase in the risk of cancers in neutered animals really is since there was no overall difference in the longevity of neutered and intact animals. If neutered animals are much more likely to get cancer, it is surprising that they tended on average to live just as long as intact dogs.
Overall, this study supports the current trend towards questioning the dogma of routine neutering for all dogs. The risks and benefits are likely to vary according to breed, age, and many other variables, and a one-size-fits-all approach is not ideal. Unfortunately, a great deal of additional research will need to be done for dog owners and veterinarians to have confidence in specific recommendations for individual dogs.

Benefits & Risks of Neutering, an Evidence Update–Cancer and Behavioral Problems in Vizslas | The SkeptVet

For me, this is the worst aspect of the vizsla study:

The data was collected though anonymous questionnaires completed by owners, often years after the events being asked about, and there was no way to confirm the accuracy or validity of these reports.

Accurate data collection is the most critical part of any study. If you have questionable data, then the results and conclusions are questionable. I almost can't believe this, but here is a quote directly from the vizsla study itself:

Procedures—Data on demographics, gonadectomy status, and age at diagnosis of disease or disorder were obtained with an anonymous online survey and analyzed.

Anonymous online surveys can be completed repeatedly in order to purposefully skew results. A good chunk of the discussion section is devoted to discussing the inherent flaws of this study, and their overall conclusion is that more research is needed on the effects of neutering in dogs. I agree that more research is needed, but I'm afraid that a lot of people will come away thinking that the results (Dogs gonadectomized at ≤ 6 months, between 7 and 12 months, or at > 12 months of age had significantly increased odds of developing mast cell cancer, lymphoma, all other cancers, all cancers combined, and fear of storms, compared with the odds for sexually intact dogs) are scientifically valid, when they are not.

[pstinard]

Originally Posted by megansmomma

The 2 posts about are pretty much what I have said in the past, as laypeople we cannot run with information from these studies for the simple reason that we are not vets. If you take the time to read each of my posts you can see there are issues with the data, the statistics and even who was used for their research. It's very obvious to me that you cannot just take these studies and use a broad sweeping brush to include every animal into the conclusions of these studies.

All it really takes is critical thinking, knowledge of the terminology, and reading the fine print that is often buried in the Materials and Methods section or in the Discussion. The entire study has to be placed in context, and the posts you quoted from Skeptvet do a good job of that. Plus, the Skeptvet is a veterinarian :

About | The SkeptVet

[107barney]

Originally Posted by pstinard

All it really takes is critical thinking, knowledge of the terminology, and reading the fine print that is often buried in the Materials and Methods section or in the Discussion. The entire study has to be placed in context, and the posts you quoted from Skeptvet do a good job of that. Plus, the Skeptvet is a veterinarian :

About | The SkeptVet

He sure is and he is really into dispelling myths and advancing real science and evidence based practices.

[megansmomma]

Originally Posted by pstinard

All it really takes is critical thinking, knowledge of the terminology, and reading the fine print that is often buried in the Materials and Methods section or in the Discussion. The entire study has to be placed in context, and the posts you quoted from Skeptvet do a good job of that. Plus, the Skeptvet is a veterinarian :

About | The SkeptVet

I find him very informative and science based in his blog regarding all types of veterinary science. IMO, he did an excellent job of breaking down how these studied wouldn't necessarily apply to the general pet population. In the future I think that I'll be referring to his blog more often, his clear writing style while addressing different issues with out pet should help the layperson understand much of what is posted on the internet regarding their health. :thumb up:

Additionally, you can ask him questions on the blog and he will respond! Love this! As a matter of fact I asked one last night and am awaiting his reply. Very excited! So instead of arguing and fighting on YT as laypeople it's very exciting to have a Vet blog and weigh in to the validity of heated topics

[107barney]

Originally Posted by megansmomma

I find him very informative and science based in his blog regarding all types of veterinary science. IMO, he did an excellent job of breaking down how these studied wouldn't necessarily apply to the general pet population. In the future I think that I'll be referring to his blog more often, his clear writing style while addressing different issues with out pet should help the layperson understand much of what is posted on the internet regarding their health. :thumb up:

Additionally, you can ask him questions on the blog and he will respond! Love this! As a matter of fact I asked one last night and am awaiting his reply. Very excited! So instead of arguing and fighting on YT as laypeople it's very exciting to have a Vet blog and weigh in to the validity of heated topics

I have liked him for a while. He is into science and evidence based practices instead of conjecture and ill-grounded opinion. I look forward to his input on the many issues that we have here. Perhaps he can be our unpaid YT veterinary consultant as you suggested