Talk:Neutering/Archive 1

Facts in new edits
I think we have this article pretty well cited, so I am going to request that any new edit presenting a new fact also be cited. I'll put something on the user's talk page, and leave the "unspayed dogs have a 25% chance of developing mammary tumors" there for the time being. --Joelmills 03:10, 17 April 2006 (UTC)


 * What bothers me the most about that claim is the lack of any reference. Is this 25% chance yearly? Over an average animal's lifetime? Does this figure include tumors which never grow large enough to be noticed? If so, how does this affect the claim that "about 50% [...] are malignant"? I'm also a bit peeved that the fact that testicular/ovarian/uterine cancers are generally neither malignant nor common seems to have been removed at the same time that this figure was added - it is not otherwise obvious that testicular cancer (for example) is much less common, and less severe, in animals than it is in humans. I've reworked the sentence to stick this back in. Zetawoof(&zeta;) 03:25, 17 April 2006 (UTC)

I'm sure 25 percent is over the lifetime of the dog. It sounds about right by my experience, but I put a request for a cite on the user's talk page. 50 percent malignancy is right, and this is from analysis of biopsied tumors, so yes, it only includes tumors large enough to be noticed, but to my knowledge, that's pretty much all of them. Mammary tumors are not shy. As to the rest of it, the contributer is a new user (and vet from their name), so I would just assume good intentions on their part. --Joelmills 03:35, 17 April 2006 (UTC)

More to do
Whew, set up article, fixed a whole lot of links and redirs, need to now add text about spaying/neutering policies and so on, but I'm out of time. Elf | Talk 23:14, 4 January 2006 (UTC)

Okay, I've put some more meat in the article. A vet or somebody could greatly improve it as well. -- RmM 12:58, 6 January 2006 (UTC)

A request/suggestion. Info on reccomended minimal age for spay/neuter(in cats and dogs) also info on early spay/neuter programs. --Dodo bird 10:06, 26 April 2006 (UTC)

What about explaining the term 'rig' for animals, particularly horses, where the castration has no change in behaviour and neutered animals still behave as if they are intact? Is this the place to cover that? --[User:Nick Wallis]] 12:20, 2 June 2006 (UTC)

The description of Bob Barker's Price Is Right spay/neuter endorsements should be clarified, specifying that he only began making these endorsements in 1981, as explained in Bob_Barker. --Cybrbeth 16:59, 25 June 2006 (UTC)

Changing the name of the article
I am moving this article to Neutering (and also its discussion section), because spaying is only neutering in females, thus already included in neutering. --Michael Retriever 15:33, 18 November 2006 (UTC)

A Little More Order
After reading this article, I decided to give some organisation to the part about advantages and disadvantages (I used BE - if someone feels like it, feel free to convert it to AE like the rest of the article). I think that the sources agree that s/n has effects, and IMO, some of them can be classified as positive, some as negative and some as ambiguous, depending on the observer's point of view. This is easier to read and understand than the previous version, where advantages and disadvantages were too often mixed in one sentence.

As a vet, I think that the article in its present state is generally well-researched and respects the NPOV policy. Given that this is a highly controversial topic, we should try and keep our statements backed up with verifyable sources from the peer-reveiwed literature.

As an aside, I also think that it would be interesting to compare the percentual importance of s/n dogs and/or cats in different countries. For example, neutering dogs is a lot more uncommon in Europe than it is in North America (although I unfortunately do not have a numeric source at the moment). Another point that could be added would be a link to a comparison of castration vs. sterilisation as a means of pet birth control. --84.72.116.141 15:56, 7 February 2007 (UTC)


 * I agree about mentioning the differences in castration frequency between the US and Europe. While I do not have exact number, I've done practice in both regions and definitely saw a difference. AFAIK, some of the Scandinavian countries even consider it illegal without a proper medical indication. Added a phrase about that in the intro; citations welcome. --130.92.9.57 14:56, 25 April 2007 (UTC)

POV in the Dog article
The tag on top mentions that a summary of this article is posted in Cat and Dog. This is highly questionable for the cat article, which does not have much information on neutering, which is why I removed the ref. The dog article, however, contains a paragraph on neutering which is strongly POV (pro) and should be adapted to the current version of the article. Since dog is protected, I put a point on it on its discussion page and thought I'd also mention it here. --130.92.9.55 11:49, 15 May 2007 (UTC)

Osteosarcoma Risk
I have edited the statement regarding the association between neutering and osteosarcoma (OSA) because it was far stronger than the citation, or the literature in general, supports. In a single study of a single breed with a known risk for osteosarcoma far higher than most other breeds, the data showed the total lifetime exposure to sex hormones was negatively correlated with the incidence of OSA. The incidence of the disease was not statistically different between neutered and intact animals overall, though it was different between animals neutered at less than 1 year of age and intact animals. And there is no reason to suggest these findings would support a general relationship between neutering and OSA incidence in other breeds or mixed-breed dogs. Given the questionable clinical significance of the finding (intact animals actually died slightly, though not significantly, earlier than neutered animals overall) and the much more thoroughly demonstrated protective benefits of neutering on life expectancy and other kinds of cancer, I do not find this study sufficient to support a general assertion that OSA risk is a meaningful disadvantage of neutering.

Brennen McKenzie, MA, VMD


 * Thanks for clarifying that. I thought it sounded a bit strong.  --Joelmills 00:45, 18 May 2007 (UTC)


 * Not quite. There is actually quite a bit more in the literature to support the notion that a correlation between neutering and osteosarcoma exists. I reverted your edit and added a few more refs to support the statement. I could add more, but drew the line at three refs all in all for the time being. The OS risk increase is irrelevant in small dogs given their low overall OS risk, but should be considered in high-risk breeds (the giant breeds and some of the large ones, such as BMD's and - as demonstrated by Cooley et al. - Rottweilers).


 * If you have articles demonstrating an overall lifespan benefit of neutering, include them under "advantages". Just make sure that they are adjusted for potential confounders, such as the fact that dogs are not neutered at birth and that not all dogs from one birth cohort may have reached the age at which others were neutered, that neutering implies full owner access to veterinary care and the motivation to use it etc.
 * --130.92.9.55 11:22, 21 May 2007 (UTC) BS, MVM

FLUTD in castrated vs. intact toms
Under "Ambiguous", the article contains the following phrase:

''Contrary to popular belief, neutered male cats are not more prone to urethral blockages than intact toms. A male cat's naturally longer, narrower urethra predisposes the animal for blockage whether it is neutered or not. Key factors in prevention include an increased fluid intake and an adapted diet.[7]''

The reference quoted to support this is a lay site (albeit a respectable one), where "studies" are mentioned without giving further references. I've just spent half an hour on Pubmed to research the possibility of such articles existing, but didn't find anything. On the other hand, a predisposition for neutered toms is mentioned in a few textbooks (references to follow). Therefore, I am under the impression that this statement is not sufficiently supported by the literature and would ask to either add better references or to delete it. --130.92.9.56 11:03, 23 May 2007 (UTC)


 * I just did my own pubmed search, and the only thing I could come up with was, "Epidemiologic study of risk factors for lower urinary tract diseases in cats", JAVMA 2001 May 1;218(9):1429-35. I read it, and the study concluded that male neutered cats were at increased risk for all types of FLUTD, including urethroliths, urethral plugs, and urethral blockage, and were in fact the most likely group for those.  It did not, however, suggest why.  Still, whatever the reason, neutered cats are more likely than intact cats to get blocked.  A significant contributing factor, in my own opinion, would be the tendency for neutered cats to be indoor cats on dry food.  So we may want to take that out of the ambiguous section and put it in the disadvantages section.  --Joelmills 02:42, 24 May 2007 (UTC)


 * I just read through this article and find it very interesting. While I have a few reservations regarding the statistical methods used (notably the lack of a Bonferroni correction), this is typical of such large-database studies. A certain number of the findings can thus be expected to be coincidental. The fact that the findings regarding the increased risk for castrated males are nearly consistent throughout the aetiologies studied and that these results reproduce the ones in the earlier study that the authors quote (Willeberg and Priester, 1976) make me think that it is safe to assume an increased FLUTD risk at least in castrated toms though, and that there is also considerable evidence that the same may be the case for some FLUTD aetiologies in females. Which means that I agree with your last phrase, unless someone can produce something from the literature to back up the current content. --130.92.9.55 11:54, 24 May 2007 (UTC)


 * All right, I'll wait a couble of days for further comments and then change it. --Joelmills 22:10, 24 May 2007 (UTC)

Vandalism by User:76.169.127.99
The said IP has vandalised the link section three times since Sept. 24, 2007. I have left two vandalism warnings on the IP talk page. Should this continue, I will request the IP to be blocked. --130.92.9.55 11:06, 8 October 2007 (UTC)

Hypothyroidism risk
Regarding the recent addition, the only assertion I'm questioning is the increased risk of hypothyroidism in neutered dogs. My copies of Compendium don't go back that far, and I could only access the abstract online, which didn't mention risk factors. The only other articles I can find are, which supports the risk, and , which does not. Thoughts, anyone? --Joelmills 03:00, 7 November 2007 (UTC)


 * My apologies, I had copied the wrong hypothyroidism reference. This has been corrected in the article. FYI, here is the abstract http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=8175472 -- Sardog1 07:28, 8 November 2007 (UTC)


 * Some quotes from the Panciera (1994) paper on hypothyroidism "Spayed female dogs have previously been found to have a higher relative risk of hypothyroidism, compared with sexually intact females [Milne KL, Hayes HM Jr. Epidemiologic features of canine hypothyroidism. Cornell Vet 1981; 71:3-14], and the association of neutering and hypothyroidism found in the present study suggests a cause-and-effect relationship." The paper then goes on to discuss the fact that the direct effect of neutering on thyroid function is mild, but that an indirect effect may be key. "More important in the association between neutering and hypothyroidism may be the effect of sex hormones on the immune system.  Castration increases the severity of autoimmune thyroiditis in mice [Okayasu I, Kong YM, Rose NR. Effect of castration and sex hormones on experimental autoimmune thyroiditis. Clin Immunol Immunopath 1981;20:240-245]."  -- Sardog1 07:45, 8 November 2007 (UTC)


 * Thanks for correcting that, it matches the first reference I mentioned above. It was only 66 dogs, however, which isn't that big a sample.  On the other hand, the authors felt it was significant, so I won't argue with it.  --Joelmills 23:41, 8 November 2007 (UTC)


 * Milne involved a larger sample of 3206 dogs, and while it found an elevated hypothyroidism risk for both neutered males and spayed females compared to their intact counterparts, in that study the risk was statistically significant only for spayed females vs. intact females. Sardog1 02:41, 9 November 2007 (UTC)


 * I think that the literature as you quote it would justify including the hypothyroidism risk under "specific to females" rather than under "general". I'll do that now. --84.72.40.134 (talk) 14:42, 22 November 2007 (UTC)

Neutering and Population Control: An Epidemiologic Perspective
While it does make both statistical and biological sense that spaying females will result in a decrease in the number of litters born, I do not see how castrating males could have that effect. Even in an (illusory) population where 99% of males are castrated, leaving a female in heat unsupervised will still result in a litter of pups/kittens. Why don't animal protection entities promoting neutering focus their limited resources on females, where their efforts actually have a chance of reducing the numbers of new dogs/cats born? --128.231.88.4 (talk) 13:44, 29 January 2008 (UTC)


 * Because a male animal cannot be everywhere at once. I honestly don't know if cats/dogs suffer the same problem humans do concerning sperm production (that is, in a couple trying to concieve, it's generally recommended then have sex every OTHER night rather then every night, so that his sperm levels will have time to reach reasonable levels again), but it is a logical assumption.  More so, in the population of pets, living with humans, castration can curb some of the more undesirable effects of owning a male animal (spraying/marking, mounting behavior, aggression, etc), and it's easier to say "Do this to all of your animals"  not just "some" of them.
 * For groups who catch, fix, and release, it's just better to do it to all animals captured. There isn't always time to ID if it's a male or female.  In both cases, the efforts are focused on both because the less viable breeding "couples" there are, the less reproduction that occurs.
 * Further, in dogs, females only come into heat ever few months. They can only breed once or twice a year.  A male dog can breed any time he finds a bitch in season.  In cats, it's a bit different.  Females go into heat and go in and out of heat every few weeks and continue to do so until they copulate.  They ovulate when stimulated to do so, so being mounted and mated biologically 'fools' them into thinking they're pregnant for a few days, then the cycle repeats.  I might be wrong about the specifics, but the base facts are pretty correct:  In both species, females can only reproduce a few times a year.  Males can reproduce year round.  There will always be another fertile male/female around.  The goal is to remove as many of them as possible from the breeding pool.  As much as we'd like, we can't STOP the numbers from rising.  There are more every day.  So every snip and chop does a bit towards slowing the numbers.
 * Also, male animals (esp. cats) have been known to kill litters that don't belong to them. if you have 9 fertile males and one fertile female in an area, that female is going to be quite harrassed by said males, and given the numbers, will probably end up loosing her litter every time she has one.  She'll go into heat again shortly there after, and the cycle begins anew.
 * Again, I am not an expert... ColbyWolf (talk) 19:31, 9 April 2008 (UTC)


 * These statements contain a lot of flawed logic. Spay/Neuter takes more time than determining an animal’s sex. Reproduction rate is controlled by the “bottleneck sex”, which in most mammals is the females – therefore, controlling their reproductive capacity will have more of an effect on the number of litters born. The point that a male dog or cat is able to reproduce all year long is irrelevant, because he can only do it when he finds a female in heat. If there are fewer fertile females around, he will have fewer chances to reproduce. An unsupervised fertile female will in roughly 99.99% of cases receive a “visit” by a fertile male, no matter how low the percentage of intact males in the population is.


 * Given that animal protection entities lack the necessary funds to neuter all fertile animals in a population, they should concentrate their efforts on females. Neutering males is frankly a waste of money if the goal is population control.


 * Consider the following scenario: We have 100 males and 100 females and the monetary resources to either spay 70 females or neuter 90 males. If we neuter 90 males and spay no females, the number of litters born will not be significantly affected. However, if we spay 70 females and neuter no males, the number of litters will decrease by roughly 70%.


 * In the end, it all comes down to the fact that all male fertility is useless for reproduction if there is not enough female fertility available, and that it is much easier to control female fertility than it is to control male fertility in a population. Unless you are able to neuter very close to 100% of males in one population, a single “snip”, even if well-intended, is simply a waste of perfectly good money. With a spay, however, you will see results on population size immediately – even if the operation costs a bit more.


 * --128.231.88.5 (talk) 15:06, 15 April 2008 (UTC)