When to sterilize

[No Imagination]

---

Members don't see this ad.

Recently I got into an augment with my cousin about his refusal to neuter his dog, despite him (the dog, and probably my cousin as well) being the cause of at least two unwanted litters. Now, my cousin is an idiot, and his arguments for not neutering reflect that.

However, after my conversation, I got to thinking, playing devil’s advocate with myself – and I think I did too good a job.

First off, I am not suggesting that we shouldn’t neuter. On the contrary, but I am beginning to doubt the value to spay/neuter before complete sexual maturity

No doubt, it would be wrong to compare human and animal sexual maturity, but what are your thoughts about waiting till maturity before you sterilize your animal (if you choose too?). (No MD would ever steralize a person prior to sexual maturity, unless medical emergency, ect.)

I cannot believe that there would be no repercussions on development with sterilizing at 8 weeks, 2 months, even 6-8 months.

Just curious if anyone choose to wait for this reason?

P.S. I’ve read 2-3 articles on the subject from each side, they each make a point, but I don’t think there is an answer yet – curious what your opinion is.

TL;DR version: Would you recommend to a responsible owner they wait until their animal has reached sexual maturity before you sterilize.

 

[VeganSoprano]

I personally think there may be something to the theory of early sterilization correlating with an increased risk of osteosarcoma in large/giant breed dogs. However, spaying a female before the first estrus cycle drops the risk of mammary cancer to near zero, so for females it may be a wash as far as individual health goes. Toy breed dogs frequently retain their deciduous teeth so I think waiting until 6 months is very reasonable so you can neuter and éxtract retained teeth in the same procedure.

As for cats, I haven't seen anything that makes me think there is a downside to sterilizing before puberty. For females, I believe there are advantages to spaying early. It only takes a second for a female in heat to slip out the door and end up pregnant. Keeping a seasonally polyestrus animal from getting pregnant for any length of time is going to be a tall order unless your living situation provides the cat with absolutely no possibility of access to the outdoors. Beyond that, my experience is that the recovery from surgery for female kittens younger than 5 months is much easier than for older animals - they barely seem to notice anything happened! There are noticeable physical differences in cats who were neutered earlier (longer bodies and extremities), but I have never seen or heard evidence that they are problematic. So for cats, given that they are such prolific breeders given the opportunity and the lack of downsides I have seen with early sterilization, I definitely can't justify waiting.

I also strongly believe that no animal should ever leave a shelter or rescue without being sterilized beforehand. A shelter's obligation is the health of the population as a first priority. Given that shelter euthanasia is the number one killer of dogs and cats, it is clear that ensuring that animals are sterilized needs to be a shelter's priority, even if it means sterilizing some individual animals at a time that may not be ideal for them. Following up with adopters to make sure they have the animals sterilized themselves is a poor use of shelter staff time and legally tricky. And when the adopter of a shelter kitten turns up 8 months later to drop off that kitten's litter of 4 kittens, the shelter has gone backward in solving the overpopulation issue!

So basically, I can see how someone could responsibly decide to delay neutering a large breed male dog until 18 months-2 years. For female and smaller male dogs, I think 6-7 months is probably the best decision on balance. And when it comes to cats, the sooner the better!

 

[sumstorm]

I chose not to alter either of my SAR dogs. One male (am cocker), one female (GSD). I opted to delay because there are several studies indicating that early alteration can put additional stress on tendons/ligaments (essentially making them less elastic) which is an issue for a working dog who is pounding the daylights out of their joints. All my other dogs were altered young or soon after obtaining them.

As for whether a shelter should alter all before departure...that can be incredibly problematic for shelters that provide 0 veterinary care; the cost of covering S/N > cost to follow up on S/N. Also, I am not comortable with extremly early spays, so shelters that have puppies to adopt out will still often need to follow up on these adoptions.

I am also hesitant to have a S/N done on a few recently adopted dogs; some dogs are anxious at a level that I think bonding may be more critical (as long as the owner is responsible) so a month or 6wk delay doesn't trouble me overly much if it improves the human-animal bond and doesn't result in extra litters.

Alot of this will depend on the purpose of the animal (working vs pet), the region you are in (do you get 100+ animals in several times a week when you only have 70 kennels....and 0 in vet care or are you a no-kill specialty rescue that adopts out at high fees or has lots of contributions.)

I do know there was some concern that early neuter of male cats might affect the UG tract.

I admit, I have regrets about altering two of my animals; the am cocker who is just amazing and breed ideal in temperment, working ability, and field structure, and a chihuahua female that just has a remarkably happy, loving, confident without brashness personality, great patella's and no other health issues. I believe in rescue (over half our animals are rescues) but there is something to be said for using excellent animals for improving a breed. Sometimes, I think some of the behavior issues that come up over time are a result of dogs with excellent temperments often belonging to responsible, altering owners!

 

[WhtsThFrequency]

so you can neuter and éxtract retained teeth in the same procedure.

I would not feel comfortable combining a sterile procedure with a decidedly unsterile one - regardless of the fact they are in different places. Maybe it is just how I was taught, but every surgeon I know would not consider doing this.

I do agree on waiting longer for giant breeds (like Danes, etc). I personally would not recommend sterilizing a Dane or Newfie until at least 1-2 years of age.

There is also the body of literature (most notable Ware et al from 1999) that links an increase in certain cancers to sterilization. So if we had, say, a Golden (at risk) with a family history of hemangio, I would feel very obligated to tell the owners about this.

An informative page by Dr.Chris Zink with good references: http://www.caninesports.com/SpayNeuter.html Whether the correlations found are causal or not, I think it is still worth mentioning.

Overall though, with a few minor exceptions due to breed,, size, and health history, I would recommend 6-7 mo sterilization. It also very much depends on the owner - personally (and this is *me*, only because I know me) I don't know if I would choose to sterilize my next dog, simply because I think it is a wash in terms of health benefits and think putting an animal through surgery and removing organs for my own convenience is...well...I have a problem with it. I am fully aware of the issues of owning an intact animal and would be responsible to that end. However, we cannot assume all owners are willing to take the necessary steps to responsibly own an intact animal....so eh.

 

[DVMDream]

so you can neuter and éxtract retained teeth in the same procedure.

I would not feel comfortable combining a sterile procedure with a decidedly unsterile one - regardless of the fact they are in different places. Maybe it is just how I was taught, but every surgeon I know would not consider doing this.

We do this quite often at the clinic I work at. We first do the sterile procedure and then the non-sterile tooth extraction and have never had a problem with it. It also prevents having to put the animal under anesthesia twice and cuts down costs to the owner since they will only be being for anesthesia and surgery time once. Just out of curiosity, why would you not feel comfortable extracting teeth at the same time as sterilizing?

 

[VeganSoprano]

We do them both at the same time all the time. We also routinely do dentals and lumpectomies in the same anesthetic event in older patients. Of course, they're not happening simultaneously! And we wouldn't do a dental cleaning with an abdominal procedure like an OHE, but puppy teeth are relatively non-gross which does make some difference.

 

[Bill59]

Just out of curiosity, why would you not feel comfortable extracting teeth at the same time as sterilizing?

The concern is the bacteremia induced by the dental work could seed the surgery site causing infection. There's not actual data on this one way or another but that's the theoretical concern.

 

[WhtsThFrequency]

^^ yes. Maybe it is just a stickler thing, and I not saying a surgeon who chooses to neuter or spay and do dental work at the same time is irresponsible...but esp. if you are doing the sterile procedure w/o intra or preop antibiotics (becoming more common, as literature indicates that such things aren't really needed for those procedures and we as vets have GOT to cut down on antibiotic usage), bacteremia from dental work may be a concern.

Like Bill59 says, it is more of a theoretical concern - but even theoretical concerns can be real ones if an infection occurs and the owners says hey, look, you did this at the same time and that is what caused it (whether they are right or wrong), and sues you. Remember that even if a suit is theoretical or even baseless, you still get stuck with the legal fees. Better safe than sorry.

 

[CanadianGolden]

I strongly believe that there are many systemic effects of sterilization procedures and that the risks may outweigh the benefits. There is certainly no significant medical reason to neuter a male dog before the age of 2-3. I don't consider BPH and prostatitis to be serious enough medical problems that I would neuter a dog to prevent them--if they became an issue I would neuter then.

As for females it is a bit more complicated but in an average dog with no significant familial history of mammary cancer I would not spay before 14 months.

http://acc-d.org/2006%20Symposium%20Docs/Duffy2.pdf

http://www2.dcn.org/orgs/ddtc/sfiles/LongTermHealthEffectsOfSpayNeuterInDogs.pdf


This paper (sorry, pubmed isn't working from home so I can't see the abstracts but it's one of these 2)

Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior.
Neilson JC, Eckstein RA, Hart BL.
J Am Vet Med Assoc. 1997 Jul 15;211(2):180-2. http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=link&linkname=pubmed_pubmed&uid=9227747



Castration of adult male dogs: effects on roaming, aggression, urine marking, and mounting.
Hopkins SG, Schubert TA, Hart BL.
J Am Vet Med Assoc. 1976 Jun 15;168(12):1108-10.



is the one usually cited regarding improvements in behavior in neutered male dogs; those of you who are familiar with primary literature will recognize the flaws in this study AND notice that the authors did not even draw significant conclusions about behavior improvements. The studies above show something very different and use more sophisticated evaluation methods.

 

[DVMDream]

As for females it is a bit more complicated but in an average dog with no significant familial history of mammary cancer I would not spay before 14 months.

For the majority of dogs you see though will you really know family history? The majority of the dogs we spay/neuter are ones that were picked up off the street and have no family history, came from a shelter that did not have spay/neuter, or came from a pet store that does not give any family history. Unless you have a dog from a reputable breeder who knows family history then it is impossible to say whether it is good to wait or not. Not only that, but it is possible that a puppy could eventually have a family history of mammary tumors but the mother dog may only be three years old (at the time you see the puppy) and may not get mammary cancer until 5,6,7, or 8. So, is it really worth the risk of waiting until 14 months or is it better to just do it at 4-6 months before the first heat cycle to give that dog the significantly reduced risk of developing mammary cancer?

As for male dogs I have not heard of any significant reasons or neutering at a young age so I do not see a problem with waiting for males. The only real problems I could see is that once that male dog becomes sexually mature he will start to look for a mate and many male dogs get hit by cars when they sense that in heat female dog that lives a few blocks away. The only real positives in male dogs being neutered at a younger age, that I have heard of, are to solve behavioral problems associated with male maturity including escaping, roaming, and aggressiveness.

Whtsthfrequency- I see what you and Bill59 are saying about the bacterima from the dental procedure possibly causing infection for the spay site. It would be interesting to see if there is any increase in infection if deciduous teeth are removed with spays/neuters vs. if they are done at separate times. Like I said earlier, the clinic I work at does this somewhat often and we have yet to have a dog come in with an infection afterwards. Although, I would assume it depends on how the surgeries are done/what order they are done in. At the clinic I work at we do the spay/neuter first and once that is completely finished we then do the teeth extractions. Again, no problems yet but I guess theoretically it could be a problem. I would think the biggest risk would be if the surgeries are being done at the same time or if the surgeon did the tooth extraction first and then the spay/neuter without changing gloves...which both ideas would just be . It would be interesting to see a study done on this to see if there is any correlation between tooth extraction causing an increase in infection at a different surgery site.

 

[CanadianGolden]

For the majority of dogs you see though will you really know family history? The majority of the dogs we spay/neuter are ones that were picked up off the street and have no family history, came from a shelter that did not have spay/neuter, or came from a pet store that does not give any family history. Unless you have a dog from a reputable breeder who knows family history then it is impossible to say whether it is good to wait or not. Not only that, but it is possible that a puppy could eventually have a family history of mammary tumors but the mother dog may only be three years old (at the time you see the puppy) and may not get mammary cancer until 5,6,7, or 8. So, is it really worth the risk of waiting until 14 months or is it better to just do it at 4-6 months before the first heat cycle to give that dog the significantly reduced risk of developing mammary cancer?

How many dogs do you know that died of mammary cancer? The studies showing that it mets frequently were done in the 60s and now mammary cancer is recognized and treated much earlier, decreasing the likelihood of metastasis. Most breeding dogs are intact until minimum 6-8 years old so there is plenty of opportunity to observe trends of mammary cancer in the lines, especially compared to hemangiosarcoma, lymphosarcoma, and osteosarcoma. Also mammary cancer risk jumps from I believe around .5% to 8% in those 2 heat cycles between 6 months and 14 months--8% is not exactly a high risk!

The only real positives in male dogs being neutered at a younger age, that I have heard of, are to solve behavioral problems associated with male maturity including escaping, roaming, and aggressiveness.

See the last paper I posted for why this is not true.

 

[No Imagination]

Also mammary cancer risk jumps from I believe around .5% to 8% in those 2 heat cycles between 6 months and 14 months--8% is not exactly a high risk!

I assume its the percent to 'develop' mammary cancer at some point in its life time?

Also, 8% is kinda high IMO

Also, and please correct me if I am wrong, but I always thought mammary gland cancer (not tumors per say) were one of the worst ones you could get. (Havn't taken small animal yet, so this is complete conjecture).

 

[CanadianGolden]

I assume its the percent to 'develop' mammary cancer at some point in its life time?

Also, 8% is kinda high IMO

Also, and please correct me if I am wrong, but I always thought mammary gland cancer (not tumors per say) were one of the worst ones you could get. (Havn't taken small animal yet, so this is complete conjecture).

Yes, that is the risk ie the percentage of dogs that develop mammary cancer. I guess we just don't agree on the risk; I do not think 8% is a high risk at all. Your dog is at greater risk of getting hemangiosarcoma or having a cranial cruciate rupture than getting mammary cancer.

Again, as I said before, the studies showing that mammary cancer is bad (ie mets quickly) were done in the 60s...monitoring and detection have improved greatly since then, as has owner observation IMO and so those numbers may not be valid. Time to detection has a major impact on metastasis rates.

 

[DVMDream]

How many dogs do you know that died of mammary cancer? The studies showing that it mets frequently were done in the 60s and now mammary cancer is recognized and treated much earlier, decreasing the likelihood of metastasis. Most breeding dogs are intact until minimum 6-8 years old so there is plenty of opportunity to observe trends of mammary cancer in the lines, especially compared to hemangiosarcoma, lymphosarcoma, and osteosarcoma. Also mammary cancer risk jumps from I believe around .5% to 8% in those 2 heat cycles between 6 months and 14 months--8% is not exactly a high risk!

But again, how many times do you actually see those breeding lines? And I am not sure if I just live in an area that sees lots of dogs with mammary cancer, but I would have to say that about 15% of the older intact female dogs we see have mammary gland cancer, including two dogs where the tumors were so large the animals could barely move. Early detection only works if the owners are willing to bring the dog in at the first sign something is not quite right. Since the economy has gone bad we have had more owners waiting months before they bring their dogs in to be seen. In those cases, the cancer has spread and spread alot. So, it is all a matter of who is the owner? Do you have family history (usually you do not, unless you only see clients who are reputable breeders)? And is it worth that increase? I mean if someone told you: Hey right now you have a 0.5% chance of getting breast cancer, but in 6 months you will have an 8% chance of getting breast cancer, wouldn't that concern you? I know that I would be concerned. That is a rather large jump in percentage, one that would have to be addressed if running a statistical analysis.

For how many dogs do I know that have died from mammary cancer: Probably around 10 give or take 1 or 2.

 

[CanadianGolden]

But again, how many times do you actually see those breeding lines? And I am not sure if I just live in an area that sees lots of dogs with mammary cancer, but I would have to say that about 15% of the older intact female dogs we see have mammary gland cancer, including two dogs where the tumors were so large the animals could barely move. Early detection only works if the owners are willing to bring the dog in at the first sign something is not quite right. Since the economy has gone bad we have had more owners waiting months before they bring their dogs in to be seen. In those cases, the cancer has spread and spread alot. So, it is all a matter of who is the owner? Do you have family history (usually you do not, unless you only see clients who are reputable breeders)? And is it worth that increase? I mean if someone told you: Hey right now you have a 0.5% chance of getting breast cancer, but in 6 months you will have an 8% chance of getting breast cancer, wouldn't that concern you? I know that I would be concerned. That is a rather large jump in percentage, one that would have to be addressed if running a statistical analysis.

For how many dogs do I know that have died from mammary cancer: Probably around 10 give or take 1 or 2.

Well, maybe mammary cancer is overrepresented in your area, or maybe you live in an area where owners are not financially able to treat small tumors preemptively. However, you're ignoring the correlation between spaying and all of these other conditions, including very invasive and almost universally fatal cancers. Now, we don't have causative studies, but the correlation between spay/neuter and OSA, HSA, and LSA in multiple studies is certainly not something to be dismissed because of a 7.5% increase in the risk of mammary cancer (something that is not nearly as poor a prognosis as hemangiosarcoma). Yes, animals can die of untreated mammary cancer. They also die of untreated HSA, but they die faster, so maybe it's easier to forget about their cases because they aren't medically managed for as long? I guarantee you have seen dogs with HSA or LSA in practice if you have also seen dogs with mammary carcinoma. Maybe HSA is less frequently definitively diagnosed because it's inside and people just euthanize rather than investigate a biopsy?

And no, if someone told me I'd have a 7.5% increase in my risk of breast cancer, I wouldn't be concerned. I increase my risk of dying by getting in a car every day, and the risk of dying in a car accident increases a lot if I never drive vs drive...but I do it anyway. etc. Driving, like leaving a female intact, has potentially significant benefits.

 

[DVMDream]

Well, maybe mammary cancer is overrepresented in your area, or maybe you live in an area where owners are not financially able to treat small tumors preemptively. However, you're ignoring the correlation between spaying and all of these other conditions, including very invasive and almost universally fatal cancers. Now, we don't have causative studies, but the correlation between spay/neuter and OSA, HSA, and LSA in multiple studies is certainly not something to be dismissed because of a 7.5% increase in the risk of mammary cancer (something that is not nearly as poor a prognosis as hemangiosarcoma). Yes, animals can die of untreated mammary cancer. They also die of untreated HSA, but they die faster, so maybe it's easier to forget about their cases because they aren't medically managed for as long? I guarantee you have seen dogs with HSA or LSA in practice if you have also seen dogs with mammary carcinoma. Maybe HSA is less frequently definitively diagnosed because it's inside and people just euthanize rather than investigate a biopsy?

And no, if someone told me I'd have a 7.5% increase in my risk of breast cancer, I wouldn't be concerned. I increase my risk of dying by getting in a car every day, and the risk of dying in a car accident increases a lot if I never drive vs drive...but I do it anyway. etc. Driving, like leaving a female intact, has potentially significant benefits.

Ok, I do not have much time now, but like you said earlier most of the studies done on spaying vs. mammary tumor development are from the late 60's. I could not find anything showing that early spaying or spaying at any time causes an increase in HSA, LSA or OSA. The only negatives I have found to spaying were slight increases in hip displasia and slight increases in urinary incontinence. I have found some recent studies that compared survival rates from dogs with mammary tumors compared to spaying time. The times included being spayed >2yrs from mammary cancer diagnosis, <2 years within mammary cancer diagnosis, and being spayed at the time of diagnosis. The main reason most dogs were living longer who were spayed later is becuase the tumors had ER-positive receptors on the tumor cells and therefore responded to hormone therapy where as those spayed earlier (>2yrs from diagnosis) tended to have ER-negative tumors and therefore hormone therapy was not an option. Also, the one study (from the 60's again, seems to be the only study) showed the increase in mammary tumor development going from 0.5% to 8% (before second estrus cycle), and at 26% (if spayed after second estrus cycle). Mammary tumors are also some of the most common cancers found in small animals. Really, there needs to be another study done on this since the earliest is from the late 60's, but I still have not found anything showing spaying and an increase in any other type of cancer. Again, I do not really have time to cite these studies at this moment, but as soon as I get back from class this afternoon I will cite the sources.

If you have any more information I would love to read it. It has been quite interesting to see all of the studies done on the benefits/risks of spaying early vs. late.

 

[CanadianGolden]

See the articles I referenced above by Sanborn and Zink. They have references to the studies showing increased incidence of OSA, LSA, HSA. Also, see the Vizsla Club of America Welfare Foundation 2008 Health Survey, which found similar statistics in Vizslas (nice because it controls for breed).

http://vcaweb.org/health.htm

The link is under Vizsla Breed Health Survey.

 

[ambulocetus]

I think that the Vizsla study was interesting - however i couldn't find where they controlled for age in the spay/neuter group. I would have thought that if there is a benefit of not having certain cancers after being spayed, then one might expect to live longer...and as we all know living longer seems to come with an increased risk of developing different cancers.

I did read a goo article in JAVMA one time:

Determining the optimal age for gonadectomy of dogs and cats
Margaret V. Root Kustritz
Journal of the American Veterinary Medical Association Dec 2007, Vol. 231, No. 11, Pages 1665-1675: 1665-1675.

In there it acknowledges that there are risks associated with spaying (such as an increase in HSA or increase in CCL tears) however the benefit of being spayed before the first heat had a much greater protective ability against mammary cancer, compared to the slight increase in HSA. The CCL tears could most likely be off set by weight control (given that spayed animals do have a propensity for weight gain.)

So for my dog, a large protective benefit for one cancer, versus a small increase in another, made it worth the anesthesia risk.

 

[DVMDream]

The viszla study is quite interesting, but there are always reservations I have when any scientific study is based off a survey. The top reservation being that: People lie. People get confused doing survies and mistakes happen (either accidently marking "yes" when actually meant to mark "no" (vice versa as well) or in people reading the survies acidentally making mistakes.)

The other thing that would have been interesting in this study would have been if they had compared age of being sterilized vs. developing HSA, LSA or OSA. Also, how are we supposed to know if the incidence of HSA, LSA and OSA were higher in neutered males or spayed females? Did neutered males have greater increase in developing HSA, OSA and LSA than non-neutered males? You can not answer that question because the study just lumps non-sterilized vs. sterilized. Also, 60% of the people who completed the study had sterilized their viszla. Where these viszlas that were developing HSA, LSA and OSA much, much older? Were they relatively young? Was early sterilization causing the increase in cancer development or was it sterilization at an older age? Also, I have read somewhere that viszlas have a particularly high chance of developing certain sarcomas than other breeds of dogs. This study also does not take into account the breakdown of mammary cancers in spayed vs. non-spayed female dogs, which would have been interesting to see if that difference is more or less significant than the difference in the development of HSA.

I could do a similar study with springer spaniels and mammary tumors, but they have an increased risk of developing mammary tumors so it would really be irrelevant.

I read the one study by Sanborn and Zink but it only has reference to that article and I do not have access to the article they referenced. So, the only study that I have now seen showing increased risk of HSA, LSA and OSA is the viszla one.

Here is a study I found showing the survival rates of dogs with mammary gland tumors compared to when they were spayed. (>2yrs of diagnosis, <2years from diagnosis, and at the time of diagnosis). This was interesting in showing that dogs who were spayed closer to or at the time of mammary cancer diagnosis had a greater survival rate than those spayed earlier. Related to ER + or - receptors on the cancer cells. The only bad thing about this study is it does not disclose the age of when the dogs were spayed or the age at when they were diagnosed. It does show though that for intact female dogs who develop mammary cancer, spaying can be an effective treatment because of the significant decrease in estrogen (only works if the cancer cells are ER +).

http://www3.interscience.wiley.com/cgi-bin/fulltext/119826839/PDFSTART

Here is another interesting report showing no significance between spaying and increased urinary incontinence. I think I may have also seen one that did show an increase in urinary incontinence and it is addressed in this article. This article does show an increase between tail docking and urinary incontinence:

http://www.sciencedirect.com/scienc...d=109269&md5=c921be8cd790c29108f98f9dc685961e


Earlier I had found a study that showed early spaying causes later closure of the epiphyseal plate of the long bones in certain breeds of dogs. This causes the spayed dogs to be taller than intact females of the same breed. Now, I have heard in kids (humans) that there is increased risk of osteosarcoma in individuals who are taller in height when compared to shorter individuals. Whether or not this is true in dogs. 😕 But, that could account for the increase incidence in OSA in spayed females. Just something to throw out there. I really wish I could find that journal article, but I can't. If I find it I will be sure to post it here.

This has been an interesting discussion. I would personally base the age of when to spay a specific dog on the breed of that dog and any family history that may be present to you. Otherwise I would say spaying either before the first heat cycle or between the first and second heat cycle is the best (much lower chances of mammary cancer development). Waiting until after the second heat cycle seems like too much of a risk to me (jumping up from 8% to 26% is huge).

 

[sumstorm]

Just quoting the data we were given last semester:

spay before first heat cycle close to 0% incidence of tumor development
spay after 1 heat cycle, incidence rises to 7%
more than one heat cycle, risk is 1 in 4

if develo tumor, approx 50% benign, 50% estrogen/progestrone receptor positive. 50% of malignant have spread by time of surgery.

Not saying anyone is wrong...but it is the oncologist's specialty that presented (his research is using dogs as models, so don't think he would have reason to use outdated info)

 

[sumstorm]

I must say, part of it will depend on where I am at. If the shelter in a small city is euthing 10k animals a year, I am more likely to encourage S/N. If the shelter gets half a dozen dogs...not quite so worried about it. maybe that is wrong, but I feel some obligation to preventing excess animals, which are a real problem in some places (often surrounding the mentality about animal management)

 

[DVMDream]

50% estrogen/progestrone receptor positive.

Just out of curiosity. Is this 50% of all tumors or 50% of the malignant tumors?

 

[sumstorm]

Just out of curiosity. Is this 50% of all tumors or 50% of the malignant tumors?

good question. I dont' have that in my notes...but I am going to assume that it is of malignant.

 

[alliecat44]

We also learned that dogs who have a benign mammary mass (50% of mammary masses) are three times more likely to develop a malignant mammary mass in the future. At the time of diagnosis, the majority of malignant tumors have already metastasized.

In other words, it's a bad, bad cancer to get.

 

[CanadianGolden]

I don't have time to go into the details...3 exams in the next 9 days...but I will say that my epidemiology course has taught me a lot about interpreting primary literature and that it's really important to know how various studies work before evaluating whether they're good or bad quality.

DVMDream, this study controls for breed differences as I said above, so in fact a study done only in ESS *is* relevant and good. We use within-breed studies to control for other factors.

Sumstorm, those numbers are approximately what I quoted. .5%, 8%, then more later. Spaying at 14 months is between the first and second heat cycles for a lot of females.


More later if I have time.

 

[sumstorm]

I don't have time to go into the details...3 exams in the next 9 days...but I will say that my epidemiology course has taught me a lot about interpreting primary literature and that it's really important to know how various studies work before evaluating whether they're good or bad quality.

Sumstorm, those numbers are approximately what I quoted. .5%, 8%, then more later. Spaying at 14 months is between the first and second heat cycles for a lot of females.

More later if I have time.

Took statistics for research scientists and engineers. have a pretty solid foundation. Of course, I can't do plug and chug stats....I have to rederive everything to be certain I am not straying, but coming from research focused college (currently a congressional model for developing research scientists), I don't doubt my skill in interpreting primary literature. With 13 years of extensive practice….pretty comfortable (sorry, but you seem to want to show competence, so just returning the favor.) I also have 9 finals over the next 10 days and a research proposal due, so not going to even get into a hot debate on which primary resources are accurate and which aren’t; I have yet to find a study that doesn’t have some flaw. That is why every study leads to the need for more studies!

I will disagree with you that 25% isn’t that high of a number (or that ‘more later’ is an accurate representation in an 18% jump). I doubt I would want to tell 50% of my clients that their dogs have tumors that were close to 100% preventable. I don’t know how many intact dogs you work with…but working with breeders, quite a few will go through the first by 7 months and the second by 13 months…. I would estimate, of the breeders I work with, we are talking 50% at minimum. I guess half is a lot, since I think 24% is a lot. And unfortunately in many places I have lived, at least half will already be bred.

I do believe we need to discuss pros and cons with our clients…but I am not going to tell your clients ‘if we wait to 14 months, your dog might have more of a chance to have a mammary tumor.’ The conversation will be ‘the risk goes from essentially 0 to 7% with the first heat cycle, then jumps to 25% at the second heat cycle.’ And I say that knowing that my shepherd went through several heat cycles because I believed her chances were low enough to justify taking the risk in exchange for her performance in SAR and we were deciding if she would be good enough for a particular breeding program (she is gorgeous, but there are better.)

Not saying we don't see the same things...but that I really believe my perspective and intent in practice will be deeply colored by the needs of the community I am in (10k dogs destroyed) and the real risk to the dog. If the risk of a S/N is very low, and the risk of increasing the unwanted pet population is high....probably going to recommend early S/N....since I doubt either of us will argue that pregnancy in a young dog isn't ideal.

 

[DVMDream]

I don't have time to go into the details...3 exams in the next 9 days...but I will say that my epidemiology course has taught me a lot about interpreting primary literature and that it's really important to know how various studies work before evaluating whether they're good or bad quality.

DVMDream, this study controls for breed differences as I said above, so in fact a study done only in ESS *is* relevant and good. We use within-breed studies to control for other factors.

.

I never said the study was bad. I just posted the questions that I had when reading the study. Yes, it is beneficial to do research within one breed to control for breed differences but that study then can not be generalized to the entire population. So, if I did a study on springer spaniels and their mammary tumor cancer rates for being spayed 1. before first heat cycle. 2. Between 1st and 2nd heat cycle 3. After 2nd heat cycle. and found out that spaying before first heat cycle only results in 0.1% of females developing mammary tumors and spaying after the 2nd heat cycle results in 50% of the females developing mammary tumors. I can not use that study as a generilization for all dogs. It is completely irrelevant except in springer spaniel populations. Now if I did numerous studies on many different breeds and saw the same general patterns amongst all of the breeds then it would be more acceptable to generalize that study amongst all dogs. But, 1 study in a breed that is susceptible to sarcomas showing that sterilized dogs have a slight increase (nowhere near the increases seen in mammary tumor development amongst the various times of heat cycles. What the study showed 4x increase for HSA vs. 7x increase for mammary tumors and that is ONLY if spaying is done between 1st and 2nd heat cycle afterwards a 24% increase?) in HSA can not then be constituted to "your dog has a greater risk of developing HSA." Especially since the viszla study only showed 4% of viszlas getting HSA (those sterilized) vs. 8% chance of mammary cancer if wait until 14 months of age (or between heat cylces whichever comes first). Also at what time/heat cycle were those viszlas spayed? There is no proof in that study that early spaying (i.e. before the first heat cycle) was the reason for the development of HSA. And again, how can you be sure that was for spayed dogs, it could have been the neutered dogs that created the difference in numbers. These are just questions I came up with/noticed. I am not saying that the study is bad, it is a good study and is very interesting. But, it does leave a lot of unanswered question. Especially, what were the differences for spayed vs. non-spayed female viszlas in mammary cancer development? Not to mention sarcomas are very, very rare much more rare than mammary tumors.

Ok...stepping off soapbox..

Good Luck on your exams!

 

[david594]

And no, if someone told me I'd have a 7.5% increase in my risk of breast cancer, I wouldn't be concerned. I increase my risk of dying by getting in a car every day, and the risk of dying in a car accident increases a lot if I never drive vs drive...but I do it anyway. etc. Driving, like leaving a female intact, has potentially significant benefits.

I could be wrong on this, but isn't going from a 0.5% risk of a cancer to an 8% risk of a cancer actually a 1500% increase in the relative risk of developing that cancer?

 

[CanadianGolden]

The relative risk is 16, or you are at 16 times greater risk. Percentage-wise, that's a 7.5% increase in incidence. Relative risks are not usually assessed in percent. Yes, 8% is 1600% of .5%, but I don't know of anyone that uses that method to compare risk in 2 groups.


Sumstorm, the comment about statistical knowledge wasn't directed at your post. I think clients should be well informed. And I'm not saying we should play down the risk of mammary cancer. But we also can't base our whole recommendation to spay on "your dog will have a higher risk of mammary cancer if left intact" and ignore the potentially deleterious effects. The behavior papers are really an eye-opener for me, especially since behavior problems are the number one reason animals are surrendered to shelters. The issue really is that Americans need to change their view of pet animals as disposable, not that animals need to be spayed and neutered. Some townships have done studies on mandatory spay neuter and no decrease in shelter intakes was observed--fwiw. In Sweden it is illegal to spay a female without a medical reason (eg a pyometra) and they do not have nearly the shelter intake levels that we have in the US.

Also, your comment on shelters is surprising to me because the responsible clients who come in for regular care are unlikely to be those relinquishing animals--why would you make a recommendation to an individual patient based on the attitude problem of the American people? Risks and benefits to your patients need to be assessed based on their individual situation (including whether the owner says they are committed and able to properly manage an intact dog) not whether the shelter has a high intake rate.

DVMDream, the results can be generalized because you've used the single breed to control for things that would vary breed-to-breed. Here, Vizsla group 1 (sterilized) controls for group 2 (intact) so any differences due to breed cancel out because both groups are Vizsla. I see what you're saying, and perhaps ideally we'd take a large group of thousands of dogs and
randomly assign them to be spayed or neutered vs left intact, but prospective trials like that rarely happen on this scale because of cost.

We definitely are not implying causation with these studies. They show association/correlation only.

Okay, back to studying. This is something I spend a LOT of time thinking about so I have a lot to say...

 

[PsyDGrrrl]

There are noticeable physical differences in cats who were neutered earlier (longer bodies and extremities), but I have never seen or heard evidence that they are problematic.

Do you have any references for this? I'm curious about why that might be. I have a feral kitten who was spayed very, very young and she is one of the longest, skinniest, long-legged-est cats I've ever seen that wasn't bred for that body type. The vet also commented on how long she is. I wonder if that has anything to do it?

 

[CanadianGolden]

Do you have any references for this? I'm curious about why that might be. I have a feral kitten who was spayed very, very young and she is one of the longest, skinniest, long-legged-est cats I've ever seen that wasn't bred for that body type. The vet also commented on how long she is. I wonder if that has anything to do it?

Yes, sex hormones close the growth plates so if you spay/neuter early it is possible for the bones to grow longer than their otherwise genetically determined length.

 

[sunshinevet]

Ok... I only browsed through most of that, but i reckon...

How many dogs/cats are affected by potentially linked health effects of speying and neutering each year?

How many dogs/cats give unwanted/cause unwanted litters each year AT AN EARLY AGE???

I would put a lot, lot, LOT of money on the latter being the bigger number!!!

Not to say there arent cases where I would recommend later sterilization. After working for a specialist surgeon for 5 years, I strongly believe there is a link between neutering large/giant breed dogs and further ligament/joint problems. But proportional to the amount of unwanted animals we see produced by young animals, I think we have an obligation to push early neutering and sterilisation - because accidents happen!

 

[Bill59]

How many dogs/cats give unwanted/cause unwanted litters each year AT AN EARLY AGE???

None, if you don't allow them unrestricted access to other breeding capable males/females.

So the risk:benefit ratio depends on the population you are dealing with. For shelter animals, early spay/neuter probably makes a lot of sense.

For a pet with a competent and committed client it may not. So like everything, you have to make specific recommendations depending on the particular situation.

 

[WhtsThFrequency]

^^ *thumbsup*

 

[CanadianGolden]

None, if you don't allow them unrestricted access to other breeding capable males/females.

So the risk:benefit ratio depends on the population you are dealing with. For shelter animals, early spay/neuter probably makes a lot of sense.

For a pet with a competent and committed client it may not. So like everything, you have to make specific recommendations depending on the particular situation.

Great answer!!! I agree totally!!

 

[NStarz]

I'd like to chime into this debate, though I have no knowledge of the pros/cons itself of the procedure in terms of medical benefits (so take what I say with a grain of salt 😉.

I work at a shelter that sterilizes every animal that leaves our building (unless there is a specific medical reason not to sterilize). If we adopt out an animal younger than 6 mos, the adopter makes an appointment with our spay/neuter clinic and the clinic then follows up if the adopter fails to show up for their appointment. We are very thorough in following up with adopters for any reason (including spay/neuter).

While many of the people on this forum may be responsible pet owners, I'd have to say that there is a great number of people that aren't as such. Because of the overpopulation problem in shelters (euthanization of healthy, adoptable animals there simply isn't room for), I am definitely on the advocation side of spay/neuter.

I am all for bettering the breed, but I would like to leave it up to the (responsible!) breeders who know their breed standards, etc (not to say that some of us don't).

In an ideal world, we wouldn't have to worry about the killing of healthy animals because of lack of space, but sadly this is the situation and if I can prevent more deaths in the long run (and potentially less health problems), then I am all for pushing spay/neuter (barring medical issues).

 

[VeganSoprano]

It's really too bad your shelter doesn't sterilize everyone before adoption. The administrative time spent on follow-up could be much better spent on spay/neuter outreach to the general public. From a shelter's standpoint, there is simply no reason to wait until 6 months - and for cats in particular, there is good reason to sterilize earlier!

 

[Highlsnds3]

I just have to add that I wish EVERY shelter would alter every animal that it adopts out BEFORE the animal goes to it's new home. I know where I live (it's very rural) none of the shelters do, they have arrangements with local vets who will do the surgery at no cost to the owner (also 1st distemper, rabies and heartworm test as NONE of this is done at the shelter!!!--Whole 'nother rant there). Too many times while I was working at one of the vet clinics did we have people make appointments YEARS and LITTERS after their adoption because they were tired of all the puppies or kittens they had to find homes for or take to the shelter. I can not even put into words how this makes me feel.

I don't think is is effective use of funds to follow up on the ones that are non-compliant. For myself, even though I am responsible (and can't imagine I'll ever feel the need to breed any of my dogs or cats), I am willing to adopt an animal that has been altered early and risk those potential problems, because that means that not even one irresponsible adopter will neglect to follow through on their contractual obligation before their animal adds to the overpopulation problem. JMO

 

[Mistoffeles]

just to toss in another factor, what about the research that proposes relationships between sterilization (at any age, but young is certainly in the picture) and age-related cognitive dysfunction later in life? considering that one of the major reasons for euthanasia in otherwise healthy geriatric animals is inappropriate behavior of the subset linked to alzheimers-type disease, would this color arguments in favor or against sterilization surgery?

sorry, no citations with me right now - i'm on a very fincky internet connection in the middle of yorkshire, and pubmed just isn't loading.

 

[VeganSoprano]

Do you have a link for that? I haven't heard of it. I think it would be hard to make a case against sterilization on this basis, though. We'd be (theoretically) talking about an increased risk for cognitive decline leading to earlier euthanasia in geriatric neutered animals vs. the huge number of young, healthy intact animals killed in shelters. I would also factor in the number of animals euthanized for highly treatable conditions (feline urinary obstructions, GI obstructions, GDV, toxicoses, injuries from accidents, etc) because the owners can't afford treatment. If cats and dogs weren't so abundant, a far greater percentage of animals would have homes where there were enough resources to properly care for them. And then a far greater percentage of animals might survive to *become* geriatric in the first place!

 

[david594]

I feel like the inherent issue here is that the people from the shelter point of view will take the herd medicine approach to whats best for the animals. While the people on the other side of the argument take the approach of what may be best for the individual animal.

 

[VeganSoprano]

I agree completely, and I think it's very important to understand the points made by both sides. In the end, every one of us, human or animal, exists both as an individual and as part of a community and the correct decision in any case must take both into account.

It's similar to the situation with human health and vaccines. I personally am vaccinated against tetanus and rabies because my job puts me at legitimate risk for these diseases. I'm vaccinated against rubella not because I'm at risk from it but so that a "herd immunity" exists in the community for the protection of potentially vulnerable individuals in the community. And I'm not vaccinated against HPV because I couldn't see how it would benefit either me or the community as a whole. But all three situations are individual decisions made by weighing the interests of the individual and the interests of the group (of which the individual is a part).

 

[CanadianGolden]

I think the real underlying issue, again, is the view of Americans that animals are disposable. I'm very very anti-animal rights but the real thing here is that if people considered the responsibility and monetary commitment made when obtaining an animal, and actually determined whether they could provide a stable home with activities, training, and appropriate vet care and other management for an animal for 10-20 years, we would not have an overpopulation issue. The problem isn't intact animals, it's lack of responsibility. I lived with an intact female and intact male for a year, and with an intact female alone for 5 years. No pregnancies. No accidental breedings at all, even when she was in estrus. I currently live with an intact male (and for a few months had an estrus female living here too) and nothing got bred then either. My intact dogs are not contributing to overpopulation and neither are those from responsible breeders.

Europe's animals are primarily intact and there's no problem there. We should be focusing on education and promoting responsible ownership and management, not spay/neuter.

 

[david594]

Europe's animals are primarily intact and there's no problem there. We should be focusing on education and promoting responsible ownership and management, not spay/neuter.

You know I had basically this same argument with another student recently. About how owners only get their animals spayed/neutered because of the behavioral convenience to them. And was this really an appropriate reason to put an animal through a surgery?

But then i proposed the idea if in his own professional opinion would he want to have it done to his own animals for just the medical benefits? And he agreed with me that he would want it done for them.

Spaying a dog is cheaper and safer than a future pyo surgery. Neutering a dog is cheaper than the supportive care when it gets hit by a car, or when it develops benign prostatic hyperplasia.... and are then neutering a geriatric patient. Extra cost of a gastropexy during a spay is peanuts compared to treating a bloat later on in life. Rabbits love their uterine adenocarcinoma.

Just because the owners elect to spay/neuter for the "wrong" reasons doesn't minimize the benefits to the animal.

 

[CanadianGolden]

You know I had basically this same argument with another student recently. About how owners only get their animals spayed/neutered because of the behavioral convenience to them. And was this really an appropriate reason to put an animal through a surgery?

But then i proposed the idea if in his own professional opinion would he want to have it done to his own animals for just the medical benefits? And he agreed with me that he would want it done for them.

Spaying a dog is cheaper and safer than a future pyo surgery. Neutering a dog is cheaper than the supportive care when it gets hit by a car, or when it develops benign prostatic hyperplasia.... and are then neutering a geriatric patient. Extra cost of a gastropexy during a spay is peanuts compared to treating a bloat later on in life. Rabbits love their uterine adenocarcinoma.

Just because the owners elect to spay/neuter for the "wrong" reasons doesn't minimize the benefits to the animal.

...except there aren't really any health OR behavioral benefits to neutering. Spaying we can argue about. Neutering...well, there's BPH/prostatitis. I don't think any human would choose neutering for themselves to prevent this, and it's not life threatening if treated appropriately, just like many other diseases, so I don't think recommending neutering for health or behavioral reasons is even remotely appropriate.

 

[nyanko]

...except there aren't really any health OR behavioral benefits to neutering. Spaying we can argue about. Neutering...well, there's BPH/prostatitis. I don't think any human would choose neutering for themselves to prevent this, and it's not life threatening if treated appropriately, just like many other diseases, so I don't think recommending neutering for health or behavioral reasons is even remotely appropriate.

In dogs you may be correct, but what about cats? There are definitely behavioral differences in intact vs. castrated cats.

And I must say, for someone who is hammering at the need for critically reading studies to provide support for arguments, it seems quite counterintuitive to use the "no human would choose it for themselves..." line of reasoning to arrive at your conclusions. Just an observation...

 

[CanadianGolden]

Well, we can't say whether an animal would rather be neutered than have BPH. I'm making a hypothesis based on humans. (I said "I think"...can't I inject my opinion into my posts?) I also don't think a doctor would recommend neutering to a human to avoid BPH--but I'm not a doctor. There's certainly no research supporting neutering as a socially or medically acceptable preventative procedure for BPH. And it's nearly impossible to even get a doctor to perform a vasectomy on a young male human, so I doubt most would agree to perform a castration. I also don't think ANY doctor would say that all humans should have an appendectomy because they MIGHT get appendicitis and the appendix doesn't do anything. It's really the same argument, if you're saying that testicles aren't needed.

Personally, having had an intact cat, I did not see behavioral issues with him at all. Just an anecdote. But some cats do mark. We don't seem to see the same health issues with spay/neuter in cats that we see in dogs--but dogs are much more heavily researched. Perhaps neutering and spaying are also detrimental for cats. People usually find intact cats to be unsuitable as pets, which is why we choose to accept the possible risks of spay/neuter for cats in exchange for the benefit of not having an induced ovulator living in our homes. Again, all about risk benefit. More research is needed in cats but it's unlikely to happen because cats are monetarily less valuable than dogs (mostly) and are apparently considered second class citizens as pets (not my opinion, just what I've been told--that people want to spend less money on care for their cats, so there's less money in researching things about cat health unless they relate to human medicine).

 

[david594]

And it's nearly impossible to even get a doctor to perform a vasectomy on a young male human, so I doubt most would agree to perform a castration.

I've yet to meet a dog who has tried to sue the vet when he was unable to reverse his castration.

Apple, say hello to Orange.

 

[nyanko]

CanadianGolden:

As a feline genetics researcher, I'd say your assessment is pretty spot on regarding the state of research funding in cats. But yes, people generally find intact male and female cats undesirable as pets for reasons directly linked to their sexual behavior. It's a totally different situation than in dogs, where the hypothesized behavioral changes are more complicated and vary more by individual temperament.

And regarding appendectomies in humans, anecdotally a friend of mine just had one a week ago that even the doctor said could have gone either way - it likely wasn't going to rupture or anything but was "slightly inflamed" and they went ahead with surgery anyway. It sucked because he was supposed to come and visit me this week (from NY) but couldn't fly because of it.

 

[CanadianGolden]

And regarding appendectomies in humans, anecdotally a friend of mine just had one a week ago that even the doctor said could have gone either way - it likely wasn't going to rupture or anything but was "slightly inflamed" and they went ahead with surgery anyway. It sucked because he was supposed to come and visit me this week (from NY) but couldn't fly because of it.

Sure--like a pyo that maybe you could treat medically or maybe you should spay. But we're not advocating prophylactic appendectomies, so prophylactic castration also doesn't make sense. 🙂 Sorry your visit was canceled. 🙁