Monday, February 18, 2013

Negatives to Early Neutering?

Should we rethink this important issue?

The last thing that an ethical animal group wants to see is an adopted animal being accidentally bred before it has been spayed or neutered. We all know that there are already more animals in shelters than there are available homes to adopt them. Thus more and more animal groups have opted for early spaying and neutering....even as young as 7 or 8 weeks for puppies and kittens. This practice has become more common in the last decade, so only recently are studies coming out that show what the effects have been on the health of dogs that have been altered at a young age. Before the practice became popular, animal groups had to follow up with every adopter, to make sure that the dog was altered at the age their veterinarian recommended (usually somewhere between 7 and 12 months of age). Unfortunately, female dogs often come into season around 6 months of age, so the adopter had to be very responsible to make sure they kept her confined during her first heat cycle.  In a perfect world, no dog would ever be adopted to an irresponsible owner, so no accidents would ever happen. Unfortunately, we don't live in a perfect world. So, for various reasons, once early spay/neuter became available, many groups decided no animal would leave for their new home until it was altered and many adoptable animals were altered when they were infants.  I am continuing to research this issue, as I recently have heard that some studies have shown increased aggression in female dogs who were spayed at an early age, as well as higher incidents of incontinence issues. I will share this information with you once I can find the studies involved. In the meantime, special thanks to Benjamin Hart at the School of Veterinary Medicine at the University of California, Davis for permission to reprint this article that goes over a recent study about early neutering.

Golden Retriever Study Suggests Early Neutering Affects Health

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 were published 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.
(photo courtesy of Patti Repko-Lucas, this is Baron, a beautiful rescue dog)

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.
(c) UC Davis School of Veterinary Medicine, reprinted with permission.

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  • IMPORTANT NOTE:  In correspondence with Dr. Hart, he stated the following:  "For shelters and adoption groups, if they want the dog sterilized before adoption, vasectomy of males and tubal ligation of females is a less invasive and less expensive approach."

(c) Melanie Schlaginhaufen, 2013, all rights reserved. For reprint permission, contact Melanie through her Knowing Dogs website,  OF SPECIAL NOTE:  Melanie supports several rescue organizations that are advocates of early spay-neuter, such as Angels of Assisi in Roanoke, Virginia.  The benefits often outweigh the risks when adopting dogs to the public at a young age. Please consult your own veterinarian when making decisions about the age at which to alter your own dog.

1 comment:

  1. I have received a handful of emails about this article. Seems those who believe it is important information are afraid to say so, for fear that animal rescue volunteers will be offended. And animal welfare & rescue people who are offended, would rather write me nasty personal email than post here for the world to see! It is okay! The important thing is to keep an eye on this research. We do NOT want to jeopardize the health of animals who are in responsible homes by altering them too early, but on the other hand, we cannot risk making the overpopulation problem worse by allowing kittens to be sent out without being altered when they recover so quickly and seem to do well in their new homes very soon after altering. Please keep an open mind...there must be a balance here. And if you come across other information on the subject, please share it with our readers, thank you!