New Study Just Released By University Of California, Davis

[labadore]

Very Interesting study released yesterday

UC Davis study regarding early spay/neuter suggest neutering affects dog health

also link to the actual study is available for viewing too

Actual Study - Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers

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

Golden retriever study suggests neutering affects dog health

February 13, 2013

Neutering, and the age at which a dog is neutered, may affect the animal’s risk for developing certain cancers and joint diseases, according to a new study of golden retrievers by a team of researchers at the University of California, Davis.

The study, which examined the health records of 759 golden retrievers, found a surprising doubling of hip dysplasia among male dogs neutered before one year of age. This and other results will be published today (Feb. 13) in the online scientific journal PLOS ONE.

“The study results indicate that dog owners and service-dog trainers should carefully consider when to have their male or female dogs neutered,” said lead investigator Benjamin Hart, a distinguished professor emeritus in the UC Davis School of Veterinary Medicine.

“It is important to remember, however, that because different dog breeds have different vulnerabilities to various diseases, the effects of early and late neutering also may vary from breed to breed,” he said.

While results of the new study are revealing, Hart said the relationship between neutering and disease-risk remains a complex issue. For example, the increased incidence of joint diseases among early-neutered dogs is likely a combination of the effect of neutering on the young dog’s growth plates as well as the increase in weight on the joints that is commonly seen in neutered dogs.

Dog owners in the United States are overwhelmingly choosing to neuter their dogs, in large part to prevent pet overpopulation or avoid unwanted behaviors. In the U.S., surgical neutering — known as spaying in females — is usually done when the dog is less than one year old.

In Europe, however, neutering is generally avoided by owners and trainers and not promoted by animal health authorities, Hart said.

During the past decade, some studies have indicated that neutering can have several adverse health effects for certain dog breeds. Those studies examined individual diseases using data drawn from one breed or pooled from several breeds.

Against that backdrop, Hart and colleagues launched their study, using a single hospital database. The study was designed to examine the effects of neutering on the risks of several diseases in the same breed, distinguishing between males and females and between early or late neutering and non-neutering.

The researchers chose to focus on the golden retriever because it is one of the most popular breeds in the U.S. and Europe and is vulnerable to various cancers and joint disorders. The breed also is favored for work as a service dog.

The research team reviewed the records of female and male golden retrievers, ranging in age from 1 to 8 years, that had been examined at UC Davis’ William R. Pritchard Veterinary Medical Teaching Hospital for two joint disorders and three cancers: hip dysplasia, cranial cruciate ligament tear, lymphosarcoma, hemangiosarcoma and mast cell tumor. The dogs were classified as intact (not neutered), neutered early (before 12 months age), or neutered late (at or after 12 months age).

Joint disorders and cancers are of particular interest because neutering removes the male dog’s testes and the female’s ovaries, interrupting production of certain hormones that play key roles in important body processes such as closure of bone growth plates, and regulation of the estrous cycle in female dogs.

The study revealed that, for all five diseases analyzed, the disease rates were significantly higher in both males and females that were neutered either early or late compared with intact (non-neutered) dogs.

Specifically, early neutering was associated with an increase in the occurrence of hip dysplasia, cranial cruciate ligament tear and lymphosarcoma in males and of cranial cruciate ligament tear in females. Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females.

In most areas, the findings of this study were consistent with earlier studies, suggesting similar increases in disease risks. The new study, however, was the first to specifically report an increased risk of late neutering for mast cell tumors and hemangiosarcoma.

Furthermore, the new study showed a surprising 100 percent increase, or doubling, of the incidence of hip dysplasia among early-neutered males. Earlier studies had reported a 17 percent increase among all neutered dogs compared to all non-neutered dogs, indicating the importance of the new study in making gender and age-of-neutering comparisons.

Other researchers on this UC Davis study were: Gretel Torres de la Riva, Thomas Farver and Lynette Hart, School of Veterinary Medicine; Anita Oberbauer, Department of Animal Science; Locksley Messam, Department of Public Health Sciences; and Neil Willits, Department of Statistics.

About UC Davis

For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has more than 33,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.

Media contact(s):

Benjamin Hart, School of Veterinary Medicine, (530) 752-1555, [email protected]

Pat Bailey, UC Davis News Service, (530) 752-9843, [email protected]

Edited February 14, 2013 by labadore

[Jed]

Thanks for posting that, labradore

[WreckitWhippet]

also very interesting that early neutering doesn't just impact on HD but also cruciate ligaments.

[tdierikx]

Specifically, early neutering was associated with an increase in the occurrence of hip dysplasia, cranial cruciate ligament tear and lymphosarcoma in males and of cranial cruciate ligament tear in females. Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females.

Damned if you do, and damned if you don't... errr!

It's nice to see a study that looked at both extremes and what issues could possibly arise from each.

T.

[labadore]

Specifically, early neutering was associated with an increase in the occurrence of hip dysplasia, cranial cruciate ligament tear and lymphosarcoma in males and of cranial cruciate ligament tear in females. Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females.

Damned if you do, and damned if you don't... errr!

It's nice to see a study that looked at both extremes and what issues could possibly arise from each.

T.

That is what I found very interesting. Whilst I wasn't surprised about the increase in HD and CCL, the rate of the increase was pretty surprising, 100 percent increase, or doubling, of the incidence of hip dysplasia among early-neutered males. I was surprised by the "Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females". I have a personal interest in Hemangiosarcoma having lost one of my Lab boys to this awful cancer and apart from the orthopaedic issues, is one of the reasons why I have not had my 3 year old Lab boy neutered. When I was doing lots of research when my boy was diagnosed with Hemangiosarcoma, I found quite a few articles on the pros/cons of neutering/speying and they specifically mentioned higher risks of Hemangiosarcoma for neutred/speyed dogs, with females having a higher risk than males, which seems to be borne out in this study as well. Also the Golden Retriever is one of the breeds with the the highest rates of this awful cancer, so I suppose the results of a study conducted on one specific breed should not be that surprising with regards to Hemangiosarcoma findings.

I am glad I have a preference for the males :) as I personally believe it is easier to manage an intact male than an intact female as I would probably be a bit paranoid with an intact female, worrying about the possibilities when she was in heat and the responsibility that goes with that. Whilst I could probably manage an intact female for a couple seasons to ensure the best orthopaedic outcome, I would not like to have to manage this for a bitch's lifetime. I take my responsibility of managing my intact male lab youngster very seriously and he is the first of my males that I have decided to keep intact due to both the orthopaedic and health benefits and his breeder is fully aware of this and very supportive. Obviously it is a personal decision and I am not advocating everybody needs to keep their dogs intact. We all know how many irresponsible dog owners are out there

[WreckitWhippet]

Specifically, early neutering was associated with an increase in the occurrence of hip dysplasia, cranial cruciate ligament tear and lymphosarcoma in males and of cranial cruciate ligament tear in females. Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females.

Damned if you do, and damned if you don't... errr!

It's nice to see a study that looked at both extremes and what issues could possibly arise from each.

T.

I don't see how, if you neuter once growth and development has finished and the dog is physically mature. Do it before they have matured and you have an substantial increase in the risk of HD and cruciate tears, do it too late in life and there's the increased risk of tumours.

Perhaps "rescue" should be looking at vasectomy and tubal ligation, as being a solution to allow for growth, development and adequate maturity. Dogs and bitches require the hormones for growth and development, so it should comes as no suprise that taking them away results in health issues.

[Brookestar]

Specifically, early neutering was associated with an increase in the occurrence of hip dysplasia, cranial cruciate ligament tear and lymphosarcoma in males and of cranial cruciate ligament tear in females. Late neutering was associated with the subsequent occurrence of mast cell tumors and hemangiosarcoma in females.

Damned if you do, and damned if you don't... errr!

It's nice to see a study that looked at both extremes and what issues could possibly arise from each.

T.

That I agree with. But it is still a poorly designed study. They did for instance only use patients. They did not go and source golden retrivers generally. And see what percentage of them had problems. They simply said, of all the Golden Retrievers that have hip displasia or CL damage, were they desexed or not. Dogs that are left intact are generally planned for breeding and one can hope that they would have superior health and conformation.

That does not mean there is no truth in what has been said, but it was an incredibly poorly designed study. They did not for instance go and look at dogs from registered breeders and see which had problems even though they had been sold as pets and desexed and which ones had been kept intact.

I am yet to see any decent study that really examines these issues from a population perspective. We know there are risks of early desexing, there are however also benefits, both health and behavioural. People come up with studies showing what they want to show which does not say that is really happening generally.

Having said that one needs to carefully consider the pro's and con's of desexing and what is planned for that dog. If one plans on doing agility with the dog for instance, then one would think that keeping them intact for longer would be a good idea. One also has to consider the behavioural affects on neuturing.

And while good owners can manage intact dogs, the amount of irresponsible ones out there, cannot. That is why shelters started compulsory desexing for all animals before sale, there was too many problems, too many dogs allowed to randomly mate, etc and no amount of educating of such people has worked. What might work for some people will not work for others.

i usually desex my dogs between 12-14 months of age, but that is me. I know how to look after them, I know how to manage the issues of them, and I know the risks of what I am doing. This is the age I have come up with for me and my dogs, in consultation with the breeders that I respect and choose to use, and which my vet has agreed with in this situation. I would not however recommend it to Joe Average with some mutt of a dog that they have absolutely no control of, and who cannot see the point of obedience training and who thinks that dogs should be allowed to have sex just like hamans do!!!

[Brookestar]

Perhaps "rescue" should be looking at vasectomy and tubal ligation, as being a solution to allow for growth, development and adequate maturity. Dogs and bitches require the hormones for growth and development, so it should comes as no suprise that taking them away results in health issues.

If desexing was done purely to stop breeding that would be fine. The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her. Hormones do that. It would be fine if we could guarantee that everyone had good fences and looked after the dogs, fact is they don't. People take dogs to parks let them off lead, and they have no control of them and no ability to get them back. If the siad dog smells a bitch on heat and all dogs with hormones will have heat cycles, the dog is gone and they wont be able to get it back. Too many dog fights start by dogs fighting about who is going to get the bitch first. Desexed dogs are significantly less likely to roam, they don't feel the need to mate, which intact dogs have, and nor are they enticed by the smell of a bitch on heat, or are they a bitch who has a need to mate during the heat cycle.

Sure if dogs have responsible owners, that train and socialise them, keep them securely confined and only let them off lead when they can control them, it would be fine. Problem is it doesn't happen. Desexing in the rescue world is only partialy done for breeding control, it is largely done for behavioural issues. And females that have tubal ligation still have heat cycles and still have all the other things that go with it. Most people cannot handle them, as simple as that.

Vesectomny and Tubal ligation may stop breeding it does not stop cancers, which desexing can do. What do we do instead just trade some joint issues with massive amounts of cancer?? Or are you saying that we then desex them all at a later age - who is going to pay for that, and who is going to even bring the dogs back in for it. Shelters used to only desex dogs over 6 months of age and give out free vouchers for those under that age to bring them back when they turned 6 months. Less than 25% of dogs were ever bought back. Over 90% of them had had at least one litter and most had been found at large a number of times as well. That does not even consider the health issues of not desexing.

It would be nice if we lived in a world in which most dog owners were responsible, sadely that is not the case. In fact I would say that the opposite is the case, that responsible dog owners are rarer than irresponsible ones.

[Dame Aussie]

I prefer not to desex my dogs. I see it as an unnecessary surgery when I'm responsible enough to keep them contained and safe.

[WreckitWhippet]

Perhaps "rescue" should be looking at vasectomy and tubal ligation, as being a solution to allow for growth, development and adequate maturity. Dogs and bitches require the hormones for growth and development, so it should comes as no suprise that taking them away results in health issues.

If desexing was done purely to stop breeding that would be fine. The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her. Hormones do that. It would be fine if we could guarantee that everyone had good fences and looked after the dogs, fact is they don't. People take dogs to parks let them off lead, and they have no control of them and no ability to get them back. If the siad dog smells a bitch on heat and all dogs with hormones will have heat cycles, the dog is gone and they wont be able to get it back. Too many dog fights start by dogs fighting about who is going to get the bitch first. Desexed dogs are significantly less likely to roam, they don't feel the need to mate, which intact dogs have, and nor are they enticed by the smell of a bitch on heat, or are they a bitch who has a need to mate during the heat cycle.

Sure if dogs have responsible owners, that train and socialise them, keep them securely confined and only let them off lead when they can control them, it would be fine. Problem is it doesn't happen. Desexing in the rescue world is only partialy done for breeding control, it is largely done for behavioural issues. And females that have tubal ligation still have heat cycles and still have all the other things that go with it. Most people cannot handle them, as simple as that.

Vesectomny and Tubal ligation may stop breeding it does not stop cancers, which desexing can do. What do we do instead just trade some joint issues with massive amounts of cancer?? Or are you saying that we then desex them all at a later age - who is going to pay for that, and who is going to even bring the dogs back in for it. Shelters used to only desex dogs over 6 months of age and give out free vouchers for those under that age to bring them back when they turned 6 months. Less than 25% of dogs were ever bought back. Over 90% of them had had at least one litter and most had been found at large a number of times as well. That does not even consider the health issues of not desexing.

It would be nice if we lived in a world in which most dog owners were responsible, sadely that is not the case. In fact I would say that the opposite is the case, that responsible dog owners are rarer than irresponsible ones.

Drop the hysterics. Leaving a dog or bitch until 18 or so months of age and allowing it to mature, will not see is suddenly develop massive amounts of cancer.

[Diva]

I prefer not to desex my dogs. I see it as an unnecessary surgery when I'm responsible enough to keep them contained and safe.

Me too.

And none of my undesexed males have been hard to handle, not even with bitches in season on the other side of a chain link fence.

Nor have I seen 'massive amounts of cancer'. Some cancers are more common in desexed dogs, the slightly increased risk of osteosarcoma in desexed animals is a factor in my decision to leave mine entire.

[Steve]

Other studies show that there is a increase not a decrease in cancers in desexed dogs.The only two cancers it prevents are in the bits that are removed .Any male mammal can get cancer in the testicles if they have testicles which is why more entire dogs get it than those which dont have testicles but having testicles still gives you only a limited risk of cancer of the testicles. These are things which have been circulated by animal activists which are biased and not all accurate.

[OSoSwift]

Tubal ligations and vasectomies are not designed to take the place of desexing, they are designed to ensure that those puppies cannot be bred from and so they also have to ability to grow to their full potential without the possibilities of pregnancy before being desexed at a more appropriate age, for example 12 to 18 months.

Yes the puppy would still need to be desexed and yes the owner would need to foot the bill. Which really if they can't afford it shouldn't be getting the pup in the first place.

[Weasels]

Do rescues ever let a dog out with a just a vasectomy?

We've been pondering our next pup, and it seems like we have to choose between rescue and early desexing or a WKC dog that we can desex at 18 months. I would prefer to get a rescue but I'm worried about the physical strain on a working + sports dog, and that early desexing might exacerbate joint risks. If we could get a vasectomied rescue pup which we can desex later that would be a nice compromise.

[Guest donatella]

I'd like to see the studies for and against desexing incorporating large and small breeds. It is interesting seeing it all unfold. I will desex my girls as I believe it is in their best interest, Pyometra being one of the nasties we want to avoid.

[OSoSwift]

This is not saying don't desex it is saying it is best left until they are mature ie after 12 months of age...............

[Leema]

The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her.

How many entire dogs have you housed/managed? With all the entire dogs I have had through care, I have never once had a dog do 'anything at all' to get to a bitch in heat. But, I admit, that's only about 10 dogs or so. Maybe you've had more entire male dogs in your care and have witnessed more of this desperate behaviour than I?

[Blackdogs]

The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her.

How many entire dogs have you housed/managed? With all the entire dogs I have had through care, I have never once had a dog do 'anything at all' to get to a bitch in heat. But, I admit, that's only about 10 dogs or so. Maybe you've had more entire male dogs in your care and have witnessed more of this desperate behaviour than I?

I agree with this. I've never had a problem with my entire male. There was a bitch on heat at the park the other day and he was certainly interested until I called him off and distracted him. You can still have control over entire dogs.

[Guest donatella]

The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her.

How many entire dogs have you housed/managed? With all the entire dogs I have had through care, I have never once had a dog do 'anything at all' to get to a bitch in heat. But, I admit, that's only about 10 dogs or so. Maybe you've had more entire male dogs in your care and have witnessed more of this desperate behaviour than I?

I agree with this. I've never had a problem with my entire male. There was a bitch on heat at the park the other day and he was certainly interested until I called him off and distracted him. You can still have control over entire dogs.

People take their dogs on heat to dog parks?

[WreckitWhippet]

The fact is males that are intact can smell a bitch on heat for miles and will do anything at all to get to her.

How many entire dogs have you housed/managed? With all the entire dogs I have had through care, I have never once had a dog do 'anything at all' to get to a bitch in heat. But, I admit, that's only about 10 dogs or so. Maybe you've had more entire male dogs in your care and have witnessed more of this desperate behaviour than I?

I agree with this. I've never had a problem with my entire male. There was a bitch on heat at the park the other day and he was certainly interested until I called him off and distracted him. You can still have control over entire dogs.

People take their dogs on heat to dog parks?

No they take bitches :laugh: