Study on spay neuter

[Teegy]

My friend received this from her allopathic vet friend.
I thought it would be great to share the information

PLOS ONE: Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers
Abstract

In contrast to European countries, the overwhelming majority of dogs in the U.S. are neutered (including spaying), usually done before one year of age. Given the importance of gonadal hormones in growth and development, this cultural contrast invites an analysis of the multiple organ systems that may be adversely affected by neutering. Using a single breed-specific dataset, the objective was to examine the variables of gender and age at the time of neutering versus leaving dogs gonadally intact, on all diseases occurring with sufficient frequency for statistical analyses. Given its popularity and vulnerability to various cancers and joint disorders, the Golden Retriever was chosen for this study. Veterinary hospital records of 759 client-owned, intact and neutered female and male dogs, 1–8 years old, were examined for diagnoses of hip dysplasia (HD), cranial cruciate ligament tear (CCL), lymphosarcoma (LSA), hemangiosarcoma (HSA), and mast cell tumor (MCT). Patients were classified as intact, or neutered early (<12 mo) or late (≥12 mo). Statistical analyses involved survival analyses and incidence rate comparisons. Outcomes at the 5 percent level of significance are reported. Of early-neutered males, 10 percent were diagnosed with HD, double the occurrence in intact males. There were no cases of CCL diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with LSA, 3 times more than intact males. The percentage of HSA cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of MCT in intact females, but the occurrence was nearly 6 percent in late-neutered females. The results have health implications for Golden Retriever companion and service dogs, and for oncologists using dogs as models of cancers that occur in humans.

Citation: 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
Editor: Bart O. Williams, Van Andel Institute, United States of America
Received: August 3, 2012; Accepted: January 4, 2013; Published: February 13, 2013
Copyright: © 2013 Torres de la Riva et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: Supported by the Canine Health Foundation (#01488-A) and the Center for Companion 330 Animal Health University of California, Davis (# 2009-54-F/M). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Introduction

The overwhelming majority of companion dogs maintained in the U.S. are spayed or castrated (both referred to herein as neutered) [1]. Increasingly in the U.S. neutering is being performed early, demarcated in the present study as prior to one year of age. The impetus for this widespread practice is presumably pet population control, and is generally considered responsible pet ownership. However, this societal practice in the U.S. contrasts with the general attitudes in many European countries, where neutering is commonly avoided and not generally promoted by animal health authorities. For example, a study of 461 dogs in Sweden reported that 99 percent of the dogs were gonadally intact [2], and an intact rate of 57 percent was reported in a Hungarian study [3]. In the United Kingdom, a 46 percent intact rate was reported [4].

In the last decade, studies have pointed to some of the adverse effects of neutering in dogs on several health parameters by looking at one disease syndrome in one breed or in pooling data from several breeds. With regard to cancers, a study on osteosarcoma (OSA) in several breeds found a 2-fold increase in occurrence in neutered dogs relative to intact dogs [5]. Another study on OSA, to explore the use of Rottweilers as a model for OSA in humans, found that neutering prior to 1 year of age was associated with an increased occurrence of OSA; 3–4 times that of intacts [6].

Hemangiosarcoma is a cancer that is affected by neutering in females. A study of cardiac tumors in dogs found that cardiac HSA for spayed females was greater than 4 times that of intact females [7]. A study on splenic HSA found the spayed females had more than 2 times the risk of developing this tumor as intact females [8]. Neither of these studies separated early- versus late-spayed females with regard to increased risk, and neither focused on just one breed. A study on the epidemiology of LSA (lymphoma) in dogs, for comparison with human lymphoma, found that intact females had a significantly lower risk of developing this cancer than neutered females or neutered males or intact males [9]. Another cancer of concern is prostate cancer, which occurs in neutered males about four times as frequently as in intact males [10]. A study on cutaneous mast cell tumors (MCT) in several dog breeds, including the Golden Retriever, examined risk factors such as breed, size, and neuter status. Although early versus late neutering was not considered, the results showed a significant increase in frequency of MCT in neutered females; four times greater than that of intact females [11].

In contrast to the rather strong evidence for neutering males and/or females as a risk factor for OSA, HSA, LSA, MCT, and prostate cancer, evidence for neutering as protection against a dog acquiring one or more cancers is weak. The most frequently mentioned is mammary cancer (MC) [12]. However, a recent systematic review of published work on neutering and mammary tumors found the evidence that neutering reduces the risk of mammary neoplasia to be weak, at best [13].

With regard to joint disorders affected by neutering, one study documents a 3-fold increase in excessive tibial plateau angle – a known risk factor for development of CCL – in large dogs [14]. A paper on CCL found that, across all breeds, neutered males and females were 2 to 3 times more likely than intact dogs to have this disorder [15]. In this study, with sexes combined, neutering significantly increased the likelihood of HD by 17 percent over that of intact dogs.

Given the widespread practice of neutering in the U.S., especially with public campaigns promoting early neutering, and the contrast with neutering practices in other developed countries, the objective of this project was to retrospectively examine the effects of neutering on the risks of several diseases in the same breed, distinguishing between males and females and early or late neutering versus remaining intact using a single hospital database. Because neutering can be expected to disrupt the normal physiological developmental role of gonadal hormones on multiple organ systems, one can envision the occurrence of disease syndromes, including those listed below, to possibly be affected by neutering as a function of gender and the age at which neutering is performed. The study focused on the Golden Retriever, which is one of the most popular breeds in the U.S. and Europe. In this breed, HD, CCL, LSA, HSA, MCT, OSA, and elbow dysplasia (ED) are listed as being of particular concern [16].

Methods

Ethics Statement

No animal care and use committee approval was required because, in conformity with campus policy, the only data used were from retrospective veterinary hospital records. Upon approval, faculty from the University of California, Davis (UCD), School of Veterinary Medicine, are allowed restricted use of the record system for research purposes. The final dataset used for statistical analyses is available to qualified investigators, upon request, from the corresponding author.

Data Collection

The dataset used in this study was obtained from the computerized hospital record system (Veterinary Medical and Administrative Computer System) of the Veterinary Medical Teaching Hospital (VMTH) at UCD. The subjects included were gonadally intact and neutered female and male Golden Retrievers, 1 to 8 years of age and admitted to the hospital between January 1, 2000 and December 31, 2009. Data from patients less than 12 months of age and 9 years or older were not considered. Additional inclusion criteria were requirements for complete information on date of birth, date of neutering (if neutered) and date of diagnosis (or onset) of the joint disorder or cancer. Patients were classified as intact or neutered; the neutering was sub-classified as “early” if done before 12 months of age and “late” if done at 12 months of age or older. For all neutered patients, the neuter status at the time of each visit was reviewed to ensure that neutering occurred prior to onset of the first clinical signs or diagnosis of any disease of interest.

[Teegy]

It's a very long read, I've only posted the beginning and the link will take you to the rest

[Lovetodream88]

Goldens are known to have issues unique to there breed also all these study's are done on large breed dogs not small breed and there is a huge difference. Not spaying your females could end up being a death sentence for them. Poymentra seems to be on the rise and will kill your dog if emergency surgery is not done within 48 hours but even then your dog still has a pretty good chance of dying after the emergency spay and even in the months following when you think you are in the clear. That and mammary cancer is not something I was willing to risk with my baby girl.

[Teegy]

Do you have some research information or case studies to show the rise and let people see the dangers. It would also be great for the uninformed if you could provide details of exactly what it is, what it does and what people should look out for, when does it usually present itself and what steps should hey take.

The only case study I could find was out of the RSPCA in the UK. 6 Special Considerations for Older Pets

[Teegy]

Please ignore the link attached. Having an issue with my phone this morning. I'll try that again

[Teegy]

Veterinary Record | Mobile

[Teegy]

In addition, the reproductive and hormonal systems in dogs do not vary from breed to breed, Pyometra doesn't just impact in fixed females, spayed ones can contract it too, not all unfixed females contract it and generally infection tends to attack a weakened immune system. So hopefully with a proper diet and a strong immune system such a life threatening illnesses risks could be kept at bay.

[Lovetodream88]

Originally Posted by Teegy

In addition, the reproductive and hormonal systems in dogs do not vary from breed to breed, Pyometra doesn't just impact in fixed females, spayed ones can contract it too, not all unfixed females contract it and generally infection tends to attack a weakened immune system. So hopefully with a proper diet and a strong immune system such a life threatening illnesses risks could be kept at bay.

Your facts are wrong you can not get an infection in a uterus that is not there and healthy dogs do get it. I'm talking about growth and such, small dogs do not take as long to grow and such so spaying to early with a large breed dog if it does mess with growth would effect them more.

[gemy]

Originally Posted by Teegy

Do you have some research information or case studies to show the rise and let people see the dangers. It would also be great for the uninformed if you could provide details of exactly what it is, what it does and what people should look out for, when does it usually present itself and what steps should hey take.

The only case study I could find was out of the RSPCA in the UK. 6 Special Considerations for Older Pets

Teegy I believe that PLOS one study was posted in another thread, but if you go to my thread Spay and Neuter - when or if ever, in the General Forum you will see the link to the Viszla study - which shows surprising low rates of mammary cancer and pyrometra.


There could be some sort of breed genetic protection against this *I suppose* but more studies need to be done to understand this.


Same thread different link this one to the *Irreverant Vet* and his review of the medical literature vs a vs health benefits and risks to the S/N question.


In there he explains that the study most often quoted to show this *marked* increase in mammary tumours is most often mis-quoted and mis understood. Apparently the risk of any mammary tumour is 1-3 in 100 dogs! Further more the study shows that of all mammary tumours diagnosed 50/50 is the ratio to benign to cancerous in dogs, in cats it is almost 100% cancerous but not Dogs. So let us take these two stats together and what you have is a .5- 1.5% chance of having a female dog with a cancerous mammary tumour. Pretty low odds, how-ever yes these odds go up with the number of heats a female has but what-ever % increase per heat would go like this :


If the study said that the risk increases after one heat by 10% then now your female has .55-1.65% of having mammary cancer according to this study. If after second heat the risk of cancer increases by 20% then the odds are now .60-1.8% again we are not talking about a huge risk.


It is my understanding that pyrometra is the more relevant concern, especially in un-bred intact older 4-5+yr old females - pyrometra is very rare in young females although it does occur. It is why many many breeders will spay their females once they are done breeding them.


The decision to s/n your dog, is turning out (as it probably always truly was) one that is more nuanced then many folks believe. There is no Band-Aid one treatment fits all approach at this point in time - in fact there never was. More recent research and just as importantly the apparent public interest in this more recent research is telling us that much more research is necessary, and that there appears to be some definite health risks along with health benefits to the S/N question.


It becomes more complicated when you look at different purebreds as for some there are compelling arguments to at least delay the S/N for some time. pstinard found one with small/toy dogs in it, but it was mainly looking at ACL or CCL tears.


At this point in time, we have not one study I have found that was a comprehensive one in toy breed dogs, that looked at a significant number of the population across a broad diversity of concerns versus benefits.


In terms specific to the Yorkshire Terrier given the zero research on this question specific to our breed, all that can guide us, is what research has been done in the past on multiple different breeds. And that research tells us there is no overt health benefit to neutering a male, and the highest risk to the female is probably pyrometra.

[Nancy1999]

Originally Posted by Teegy

In addition, the reproductive and hormonal systems in dogs do not vary from breed to breed, Pyometra doesn't just impact in fixed females, spayed ones can contract it too, not all unfixed females contract it and generally infection tends to attack a weakened immune system. So hopefully with a proper diet and a strong immune system such a life threatening illnesses risks could be kept at bay.

Not sure where you got this information, but you might want to take a look at this link: Pyometra cannot occur if there is no uterus. Pyometra: More Than a Uterine Infection While it's true, any illness probably occurs when the immune system is weak, so proper diet, exercise, etc., are important, we really never know what will weaken the immune system and simply getting older could do it.

[Teegy]

My dogs were still growing at a year and a half to two, so I'm basing this statement on my experiences.
The chances of an infection developing in a healthy environment are a lot less than those of a dog with a weakened immune system. But like many illnesses often they are tie to the genetic makeup of a dog.
Do you have an good resources other than the one from the RSPCA that we can share with everyone else regarding this nasty infection. So many people an still uninformed about so much and are new dog owners, this is good info for them to know.

[Teegy]

Yes a few people that I know said their older dogs contracted it.

[gemy]

Was it called stump pyrometra?

[ladyjane]

Originally Posted by Teegy

My dogs were still growing at a year and a half to two, so I'm basing this statement on my experiences.
The chances of an infection developing in a healthy environment are a lot less than those of a dog with a weakened immune system. But like many illnesses often they are tie to the genetic makeup of a dog.
Do you have an good resources other than the one from the RSPCA that we can share with everyone else regarding this nasty infection. So many people an still uninformed about so much and are new dog owners, this is good info for them to know.

There is an abundance of information on the web....all one has to do is google : pyometra dog

Pyometra in Small Animals: Reproductive Diseases of the Female Small Animal: Merck Veterinary Manual

Pet Health Resources | Disease | Pyometra in Dogs | University Animal Hospital

Signs & Solutions of Pyometria in Dogs | VCA Animal Hospitals

Pyometra | AKC Canine Health Foundation

[Teegy]

One person I know mentioned stump, yes