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An Alternative to Surgery to Sterilize Male Dogs

Story at-a-glance

sterilized-dog

  • An injectable chemical sterilization drug will be available for use in the U.S. by the end of this year. It is currently FDA-approved only for dogs from 3 to 10 months, but the manufacturer believes it will be approved as safe for all dogs 3 months and older by the time it is released.
  • The drug, brand name Zeuterin, contains zinc gluconate neutralized by arginine. It acts as a spermicide and causes irreversible fibrosis of the testicles, which eventually atrophy and shrink in size, but remain visible.
  • Upon its initial release, Zeuterin will be made available primarily to shelters and spay-neuter clinics. The drug can only be sold to licensed veterinarians who have been trained in the injection procedure by the manufacturer.
  • The drug is highly effective at sterilizing male dogs with a single injection in each testicle. There are some side effects which seem primarily related to the injection technique.
  • It’s important to understand no sterilization procedure is completely risk-free, short or long-term. Once Zeuterin is widely available to private veterinary practitioners, we encourage dog owners to discuss with their vet the pros and cons of the procedure vs. traditional spaying or neutering.

By Dr. Becker

An injectable sterilization product for male dogs containing zinc gluconate neutralized with arginine is scheduled for release in the U.S. by the end of this year under the brand name Zeuterin ("zinc neutering"). The product is already in use in Bolivia, Columbia, Mexico and Panama under another name.

The drug is effective for permanent sterilization of male dogs at least three months of age. Zeuterin has been approved by the FDA for use in dogs three to ten months of age and can be obtained only by licensed veterinarians who have received training from the drug’s manufacturer, Ark Sciences, in how to perform the injections. The manufacturer believes the drug will be approved for use in dogs of any age over three months before the U.S. release date.

The drug functions as a spermicide and causes irreversible fibrosis of the testicles, which eventually atrophy and shrink in size, but remain visible. Dogs receiving the injection are tattooed in the groin area as proof they are sterile.

Product Launch Aimed at Shelters and Spay-Neuter Clinics Across the U.S.

Many shelters and spay-neuter facilities don’t have the recovery space for animals after sterilization surgery. For those organizations, Zeuterin should save time, money and space.

The injections are done on an outpatient basis, no anesthesia is involved, and dogs can be released relatively quickly after the procedure. Shelters and spay-neuter programs can then transfer some of the resources formerly committed to neutering male dogs toward spaying females and other outreach programs.

Proponents of Zeuterin believe it is unlikely individual veterinary practitioners will immediately embrace the sterilization drug, simply because they are already equipped and trained to do surgical spays and neuters. In addition, at this time Ark Sciences is training only a limited number of private veterinarians to inject Zeuterin.

Pet owners who want to have their male puppy chemically sterilized can add their names to a waiting list, which will at some point trigger Ark Sciences to send an offer to their vet to get certified to inject Zeuterin. According to Ark Sciences, the waiting list will be worked on a first-come first-served basis when the product becomes available.

It’s impossible to predict when Zeuterin might be widely available as an option for private vet practices and individual pet owners. Whenever that time comes, I think it’s important to understand the potential risks and benefits of this method of sterilizing male dogs.

Technology Approved by FDA in 2003

The formulation of zinc gluconate neutralized by arginine was actually approved by the FDA in 20031. That same year the drug was produced by Pet Healthcare International and distributed in the U.S. by Addison Laboratories under the name Neutersol.

According to Ark Sciences, Addison Labs overestimated the demand for the drug and created too much inventory. Excess inventory expired in two years, Pet Healthcare International went unpaid, and production shut down. Addison Labs and Pet Healthcare ended their relationship in 2005.

Ark Sciences subsequently acquired all rights to the Neutersol technology and has been distributing the product in Mexico and three other countries under the name Esterilsol for the last four years. They have used the drug extensively in Mexico in dogs three months and older to further evaluate its effectiveness as a sterilization agent, as well as to refine and improve the injection technique.

How the Drug Works as a Sterilization Agent

According to the Alliance for Contraception in Cats and Dogs (ACC&D) in their April 2012 Product Profile and Position Paper2 on Zeuterin:

As with any medical intervention, safety and effectiveness depend upon proper administration. The exact mechanism of action is not known. The following is based on a description provided by Ark Sciences. The product should be administered as an intratesticular injection into the center of the testicle via the dorsal cranial portion of testicle, parallel to the longitudinal axis. After injection the compound diffuses in all directions from the center of the testis. In the concentration used, zinc gluconate acts as a spermicide and destroys spermatozoa in all stages of development and maturation. It results in permanent and irreversible fibrosis in the seminiferous tubules, rete testis and epididymis. This produces a reduction in the size and texture of the testicles and permanent sterilization. Testosterone production is reduced by 41-52%, and the endocrine feedback system remains intact. Zinc gluconate is absorbed and metabolized by the body within 72 hours after the injection.

Also, from the Ark Sciences FAQ web page3:

How is testosterone lowered by Zinc Gluconate neutralized with Arginine?

The dosage and concentration is designed to ensure Leydig Cells in the interstitial space of the testes survive the procedure. Stimulated by Luteinizing Hormone (LH) produced in the pituitary gland, the Leydig Cells continue to support testosterone-related metabolic activity and growth. In the absence of spermatogenesis, Sertoli cells stop communicating the need for testosterone to mature sperm cells. The pituitary gland detects this lowered demand and lowers the LH levels. Since LH levels determine how much testosterone is produced by the Leydig cells, overall testosterone levels are reduced by 41-52% for all dogs permanently.

Zeuterin Adverse Reactions

The 2003 FDA drug approval document includes a study of 270 male puppies injected with the chemical sterilant. The puppies were a combination of shelter animals and family pets.

The following reactions were noted:

Reactions Upon Injection
Local Reactions

Reaction
Dogs Affected
Reaction
Dogs Affected

Vocalization
6
Scrotal Pain
17

Kicking
1
Scrotal Irritation
3

Biting and Licking
2

General Reactions
Scrotal Swelling
2

Reaction
Dogs Affected
Scrotal Dermatitis
2

Leukocytosis
2
Scrotal Ulceration
1

Neutrophilia
17
Scrotal Infection
1

Vomiting
12
Dry Scrotal Skin
1

Anorexia
11
Scrotal Bruising
1

Lethargy
6
Preputial Swelling
1

Diarrhea
5
Scrotal Sore
1

Another zinc gluconate sterilization study was done in the Galápagos Islands and published in 2008. It was conducted in a cooperative effort by the University of Florida, the ASPCA, and Animal Balance of San Francisco, and titled "Comparison of intratesticular injection of zinc gluconate versus surgical castration to sterilize male dogs."4 The following observation was made by the researchers:

Although the complication rate was similar for surgical and zinc-gluconate castration, the zinc-gluconate reactions were more severe. Surgical wound complications were treated by superficial wound debridement and resuturing. In contrast, zinc-gluconate reactions required antimicrobial treatment, orchiectomy, and extensive surgical debridement and reconstruction, including scrotal ablation in 2 dogs. These reactions occurred following administration by both experienced and novice individuals. All dogs made a full recovery following treatment of zinc-gluconate reactions and incisional dehiscences.

The authors of this study determined that proper injection technique is critical because injection or leakage into surrounding tissues can result in severe tissue damage. And while scrotal swelling and tenderness are common in the first days after injection, a more serious reaction is the development of scrotal ulcers or draining tracts in the scrotal or preputial area. The self-trauma that follows can be severe.

The researchers also observed that lesions aren’t always restricted to the injection site, which could indicate the solution may spread beyond the target area.

Long-Term Side Effects

According to Ark Sciences, since 1999 when the initial clinical studies were performed, there have been no reports of long-term side effects.

I would just add here that whenever we manipulate nature sufficiently to stop procreation, there WILL be long-term side effects. This is true for spay/neuter, and any other method. We are just beginning to understand the lifelong implications of surgical removal of ovaries and testicles, yet spaying and neutering of cats and dogs has been a common practice for decades.

I’m certainly not against the sterilization of pets. I’m a proponent of assessing the risks and benefits of everything we do as guardians of the animals in our care.

You can read more about Zeuterin on the Ark Sciences FAQ page as well as the other documents linked in the references, below.

Once the product is widely available to private veterinary practitioners, if you’re considering it, I recommend talking with your vet about the pros and cons of the procedure for your own dog.

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Pet Sterilization Laws Raise Health Concerns

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August 17, 2012 Posted by | Adopt Just One More Pet, Animal or Pet Related Stories, Animal Related Education, Dogs, Dogs, If Animlas Could Talk..., Just One More Pet, Man's Best Friend, Pet Friendship and Love, Pet Health, Pets, responsible pet ownership | , , , , , , , , , , , , | 4 Comments

March start of kitten, puppy season…

By LARISSA GRAHAM/The Lufkin Daily News

 This year, Lufkin Animal Control will take in approximately 7,000 dogs and cats for a variety of reasons, whether they are surrendered by their owners, dropped off as strays, or caught by animal control.

Of those, only 10 percent of the dogs and 2 percent of the cats will make it to new homes. The rest will be euthanized to make room for a constant flow of incoming animals.

According to Rhonda McLendon, director of Lufkin Animal Control, March marks the beginning of puppy and kitten season, when the shelter will see a huge increase in the numbers of puppies and kittens left with them.

“Unfortunately, a lot of folks out there bring us puppies and kittens. Almost every day this time of year we’ll get a litter,” McLendon said.

During the summer, the shelter will take in anywhere from 600 to 1,000 animals a month.

“We’re taking in vast numbers and we’re adopting a few and getting a few back to their owners and a few to rescues,” McLendon said. “The numbers are pretty ridiculous.”

The reason for their staggering intake numbers, McLendon said, is because people are allowing their pets, whether by choice or by accident, to reproduce.

“Way too many animals are being born, and there just aren’t enough homes out there for them,” McLendon said.

McLendon hopes that education will encourage more people to choose to spay or neuter their pets.

Currently, the city of Lufkin works with Southwood Drive Animal Clinic, allowing all animals adopted from animal control to be spayed or neutered for a much lower fee than a veterinarian would normally charge. The Humane Society has a low-cost spay and neuter program, as does O’Malley Alley Cat, which also offers trap-and-release programs.

“There’s folks out there that you can go to and get help for spay and neuter, but a lot of folks don’t because they don’t realize how bad the overpopulation problem is. They’re used to seeing their dog and their neighbor’s dog and maybe a few puppies. But if you come in here every day for a week you would be astounded at the number of animals that come through here,” McLendon said.

According to McLendon, the shelter’s capacity varies depending on the time of year. By the end of March, McLendon expects to house between 150 and 175 animals, with around 200 a day during the summer months. Because the shelter acts as an evacuation center, anywhere from 450 to 500 animals may stay there during a hurricane evacuation.

“Numbers are fairly high because the incoming animals fluctuate all the time,” McLendon said.

Dogs usually remain up for adoption for 30 days, depending on their health, temperament, adoptability and the time of year. During the summer months, dogs are euthanized at a faster rate because of a higher intake.

Cats do not stay as long, due to higher intake and lower adoption rates. On average, cats are euthanized after three weeks, but that drops down to two weeks during kitten season.

“Unfortunately there’s not a whole lot of folks that come to the shelter to adopt a cat,” McLendon said.

More smaller dogs are coming into the shelter than they did in previous years, McLendon said. There has been a problem with people trying to sell dogs at Walmart without a breeder permit, she said.

In order to sell dogs in Lufkin, one must have a permit, pay the applicable fees and, if the breeder lives inside city limits, go through an inspection. Out-of-town sellers still need the proper paperwork in order to sell dogs, McLendon said.

“Even if you’re selling them from your own home, as long as you’re in city limits, you need a permit,” McLendon said.

In addition to education about spaying and neutering, McLendon hopes to dispel some rumors surrounding dogs adopted from animal shelters.

Approximately 25 percent of all dogs that end up in shelters are pure bred, McLendon said.

“We see pit bulls and labs all the time,” McLendon said. “An enormous number of those come into the shelter.”

However, Animal Control will also see popular breeds like dachshunds, schnauzers, chihuahuas and poodles.

“Unless you’re wanting something that’s unusual, then the shelter has either got one or will be getting one. We’ll get the Yorkies in and we’ll get Akitas and some of the breeds that are not seen very often, too,” McLendon said. “We get a little of everything.”

According to McLendon, people will often bring in entire litters of lab puppies, believing that because they’re cute they’ll be adopted.

“There’s a good chance they won’t even go up for adoption because that same day I may get three or four more litters, and there’s so many,” McLendon said. “We’ll have 30 or 40 puppies come in and only two or three of them will get selected for adoption.”

Black dogs and cats have even less of a chance of adoption, McLendon added.

“The black labs are adopted less than any other dogs, and the black lab is the number one dog we see,” McLendon said.

When it comes to pure-bred cats, Animal Control sees mostly Siamese, though they will get other breeds on occasion.

“If you’re not wanting to spend a ton of money on a pet that is show quality, this is a good place to come,” McLendon said. “What we put up for adoption are high-quality pets.”

Another myth McLendon wants to put to rest is the idea that a dog goes into a shelter because it has temperament issues, or is sick or injured.

“We do get the ones that are sick, injured or with temperament problems, but we don’t put them on the adoption rows,” McLendon said. “The reason they’re here is because someone turns them in, they’re caught, or their owner surrenders them.”

McLendon stressed the importance of pet ID tags. According to McLendon, 95 percent of lost animals that are not wearing ID tags will not be reunited with their families.

In East Texas, many people believe their children need to see a pet have a litter of babies, McLendon said. However, she added, that is not the case.

“(Children) go through the birthing process in their science classes,” McLendon said. “What your kids need to learn is pet responsibility, and when you’re allowing your pet to have puppies or kittens that are not guaranteed homes from now on, chances are that one of them or their babies will come to the shelter are very high.”

There are just not enough homes for the massive intake of animals, McLendon said. If parents want their children to interact with puppies or kittens, or see pregnant pets, they are welcome to visit the shelter. There, children will be allowed to play with the puppies and kittens as long as they like.

“Teach (your kids) responsibility as far as pet overpopulation. It’s only going to get better when people are spaying or neutering,” McLendon said.

Other common misconceptions, McLendon added, include the belief that it is unhealthy to spay a female pet before she has had a litter of babies, and that animals who have been fixed will become fat or lazy. In female dogs, there is a much lower occurence of some cancers if they are spayed before they have puppies. Males who have been neutered are less likely to roam and get into fights over females. In addition, McLendon said, they may not be as territorial as a male dog who has not been neutered.

As for becoming fat and lazy, McLendon added that some dogs who become overweight were already predisposed to obesity, or they could be overfed. Spaying or neutering does not change activity level, McLendon said.

While a puppy may be cute, McLendon warned against adopting just for the ‘cute factor.’ While the puppy stage does not last long, it brings with it the chewing stage, along with the need for housebreaking and proper socialization. Some dogs in the shelter are already housebroken and may have been raised with children. In addition, the risk of chewing is greatly lower in adult dogs because they have already passed the teething stage.

“There’s just a lot of great things about adopting an adult dog,” McLendon said.

For more information on Animal Control or animals up for adoption, anyone interested may contact Animal Control at 633-0218.

Larissa Graham’s e-mail address – is: lgraham@lufkindailynews.comThe Lufkin Daily News

Being a pet parent requires responsibility and love, just like we give our human children, grandchildren and charges.  Part of being a responsible pet owner is making reproductions decisions and making sure there are homes for the pus and kittens, if there are some.  And those decisions is not always as one sided or uncomplicated as it may seem:

No Kill Nation: MANDATORY SPAY NEUTER LAWS ACROSS AMERICA HAVE LED TO:
▪ more animals killed
▪ more animals impounded
▪ increased animal control costs
▪ decreased licensing revenues.

www.floridaanimallaws.org

Ask Marion – JOMP

Posted:  Just One More Pet

March 10, 2010 Posted by | Adopt Just One More Pet, Change Number of Pet Restrictive Laws. Ordinances and Rules, Just One More Pet, Pet Adoption, Pet Friendship and Love, Pet Owner's Rights, Pets, responsible pet ownership, Stop Animal Cruelty, Stop Euthenization, We Are All God's Creatures | , , , , , , , | Leave a comment

Grave Risks From So Many Stray Dogs and Cats

Dog taking care of her puppies

The United States has made remarkable advances in the pet overpopulation problem over the past 20 years. Yet animals are still euthanized every day in shelters.

The Alliance for Contraception in Cats and Dogs, an organization dedicated to the humane control of dog and cat populations worldwide, wants to put an end to this.

The benefits of nonsurgical sterilization would extend beyond the stray, feral and homeless animal population, to saving human lives in countries that haven’t even begun to tackle the dog and cat overpopulation problem.

By linking nonsurgical sterilization of animals to saving human lives in developing countries, animal lives will be saved there as well.

Sources:

dvm360

There is a homeless small animal problem, not just here in the U.S., but in every country on earth.

This is a tragic situation measured only in part by the four million cats and dogs euthanized every year in U.S. shelters.

It’s estimated there are tens of millions of feral cats in this country alone. In other countries, exploding populations of feral dogs are the problem – for example, there are an estimated 30 million unowned dogs in India.

The Problems Posed by Too Many Homeless Animals

Free-roaming cats and dogs present a number of health problems, among them:

  • They are a health threat to people and pets. Rabid dogs are the number one cause of rabies deaths in humans. Over 20,000 people die of rabies in India every year, many of them children, and the vast majority contract the disease from dog bites.
  • They negatively impact the environment and animals in the wild.
  • Their welfare is at risk. One study showed that over half of homeless kittens are killed by either a dog or an automobile before they reach six months of age.

Clearly, dog and cat overpopulation is a situation the world needs to get its arms around. As custodians of the planet, it is our responsibility to alleviate the suffering and other risks associated with this massive and growing problem.

An Urgent Need for Spay/Neuter Alternatives

Spaying and neutering is a more viable option in some areas of the world than others.

Surgical sterilization requires a medical facility and equipment, anesthesia, recovery time in a safe, protected environment, and the services of a trained veterinarian.

These resources aren’t readily available for the human population of many countries, much less homeless animals.

Even here in the U.S. where spaying and neutering resources are in ample supply, the cost can be prohibitive for individual pet owners as well as animal organizations tasked with sterilizing hundreds, thousands or even millions of unowned cats and dogs each year.

The feral population poses its own unique challenges. These dogs and cats must be trapped, sterilized and released, because in most cases there’s nowhere to house them during the recovery period. In addition, follow-up care to remove surgical stitches isn’t feasible.

Due to the size of the homeless animal population throughout the world and the lack of resources in many areas to perform the surgery or provide aftercare, alternatives to spaying and neutering are desperately needed to control the rate of reproduction and ultimately, to save lives.

Nonsurgical Contraception

According to the Alliance for Contraception in Cats and Dogs, an ideal nonsurgical form of contraception would be:

  • Safe
  • Effective
  • Affordable
  • Permanent
  • Delivered in a single injection or treatment
  • Available for dogs and cats of both sexes

Current research and development of nonsurgical contraceptive products falls into two main categories: contraceptive drugs and chemicals, and immunocontraception.

The first group includes implants, injections and chemicals that interfere with the reproductive hormonal milieu or the activity of the gonads.

Immunocontraception agents are vaccines designed to produce antibodies to suppress normal reproductive function.

Comparison of Nonsurgical Contraceptive Products

Nonsurgical Contraceptive Products Comparison

As you can see from the table above, only chemical castration currently meets a majority of the criteria set forth by the Alliance for Contraception in Cats and Dogs.

Availability of Nonsurgical Alternatives

  • Gonazon and Suprelorin, which are delivered through implants, are available in some countries in Europe. Suprelorin has also been approved for use in Australia and New Zealand.
  • Acyline and VCD are still under development.
  • There are two chemical castration products in existence: Neutersol and an identical formulation called EsterilSol, which became available in Brazil about a year ago. Both products are delivered by injection.
  • Neutersol is the only nonsurgical contraceptive product approved for use in the U.S. Unfortunately, it hasn’t been available here since 2005, when the patent holder and marketer severed their business relationship.
  • All immunocontraception vaccines are still under development.

Are These Drugs Safe?

In the case of Gonazon and Suprelorin, no negative short term (one to two year) health consequences have been noted.

Short term side effects noted for Neutersol (the chemical castration product) include some pain immediately following injection, ulcers at the injection site which were resolved by changing the injection technique, and more severe reactions at the injection site, some requiring surgery.

Long term side effects of nonsurgical contraceptive products on the health of dogs and cats are unknown at this time, but there will undoubtedly be some. It’s not possible to fool Mother Nature in such a significant way without consequences.

I am not advocating these drugs. However, when you consider the alternative, which is to allow the uncontrolled breeding of hundreds of millions of homeless dogs and cats to continue, it’s easier to defend the risks involved in a nonsurgical medical intervention that can help save the lives of millions of animals, as well as people, across the world.

If You Have a Dog or Cat in Need of Contraception

If you live in the U.S. or other countries where access to pet care is plentiful and owned dogs and cats are treated as beloved members of the family, you have a number of options to choose from in controlling your pet’s reproduction.

For example:

  • You can choose to spay or neuter your pet as a puppy.
  • You can plan the surgery based on your pet’s level of development.
  • You can discuss the feasibility of alternative surgeries with your veterinarian, such as tubal ligation or vasectomy.
  • You can even choose to leave your pet intact, since as a responsible pet owner who is providing your dog or cat a forever home, you are committed to preventing any situation in which your pet would have an opportunity to breed

For a discussion of the risks and benefits of a variety of surgical sterilization techniques, you can read here.
Again….I am not recommending these drugs, simply bringing it to your attention that we have a major overpopulation issue around the world, with no current viable solutions.

Source:  Dr. Karen Becker

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March 2, 2010 Posted by | Adopt Just One More Pet, Animal or Pet Related Stories, Pets, responsible pet ownership | , , , , , , , | Leave a comment

Pet Sterilization Laws Raise Health Concerns

Spayed or neutered dogs more at risk for cancers, other ills, research shows

Studies have found that spayed or neutered dogs are at increased risks for problems including certain cancers, thyroid disorder, incontinence and some of the same behavior issues that the surgeries are said to prevent.

As legislators push for more mandatory spay and neuter laws for pets as young as 4 and 6 months in hopes of reducing the number of unwanted animals, critics are crying foul over research showing that such surgeries may raise certain health risks in dogs and therefore shouldn’t be required.

Studies have shown that dogs that undergo spaying (removal of the ovaries and uterus) or neutering (removal of the testicles) are at increased risks for certain cancers, thyroid disorder, incontinence and some of the same behavior issues, such as aggression, that the surgeries are said to prevent.

Most of these problems aren’t common to begin with, and the increased risks can depend on the type of dog and the age the surgery is performed. Still, the findings are leading some experts to say that, contrary to conventional wisdom, later spay/neuter surgery for dogs, and even vasectomies for male canines, may be better options for some animals, depending on such factors as breed and lifestyle.

The American Veterinary Medical Association has not taken a stand on spay/neuter legislation, but the American College of Theriogenologists, a group of veterinary reproduction specialists that advises the AVMA, is considering a position paper opposing the legislation at its meeting in St. Louis in August, says veterinarian John Hamil of Laguna Beach, Calif., a member of the group’s task force that looked at the issue.

“What they’re saying is that because there have been problems associated with spay/neuter surgery, they think it’s improper for it to be mandated, much less at an early age,” says Hamil. “They feel the decision should be made after discussion between the owner and veterinarian.”

Proponents of spay/neuter legislation say it’s a way to reduce the numbers of animals in shelters and cut down on euthanasia rates. They also cite the health and behavior benefits of the procedures, such as prevention of mammary cancer, spraying and marking territory, and roaming.

Patty Khuly, a veterinarian in Miami, says a better solution to control the animal population than mandatory spay/neutering by a certain age is to offer the surgeries at lower costs so more pet owners can afford them and get them done according to a veterinarian’s recommendations.

“I don’t believe that the fourth month is a reasonable window,” she says. “Most veterinarians would agree on that. I think low-cost spay/neuter, making it more available, is the solution, as opposed to mandating a time frame, especially when we don’t know the real impact of early spay/neuter.”

For more than a decade, the cities of San Mateo and Belmont in California have required sterilization of most cats and dogs more than 6 months old. But more attention is being paid to the pros and cons of pet sterilization now because of a recent spate of legislation that has been passed or introduced. Los Angeles, for instance, passed an ordinance requiring cats and dogs more than 4 months old to be neutered or spayed by October or risk fines up to $500. Palm Beach, Fla., and North Las Vegas also have approved such measures, and dozens more cities and counties, including Chicago and Dallas, are considering them. Rhode Island is the only state to have passed a mandatory spay/neuter law, and it applies just to cats.

No one-size-fits-all answer
The idea that pets should be spayed or neutered at approximately 6 months of age or earlier dates to studies in the 1960s and 1970s showing that spaying a female before her first estrus cycle almost eliminated mammary cancer — which is common in dogs — and that spayed and neutered dogs showed a decrease in behavior problems that can be fueled by sex hormones.

Spay/neuter surgery also has other benefits, including prevention of unwanted litters, no messy twice-yearly estrus cycles in females and a reduced rate of uterine infections later in life. Spayed and neutered dogs and cats also have longer lifespans.

Since the early studies were conducted, however, research has also shown downsides to the surgeries beyond acute side effects such as bleeding and inflammation.

Margaret V. Root Kustritz, a veterinary reproduction specialist at the University of Minnesota, reviewed 200 studies and found that while spay/neuter surgery has benefits, it is also linked to increases in the incidence of certain diseases and conditions such as bone cancer, heart tumors, hypothyroidism and canine cruciate ligament (CCL) injuries, as well as prostate cancer in male dogs and urinary incontinence in females. The extent of the risk can depend on the problem, as well as the size and sex of the dog, and the age the surgery is performed.

The risk of a type of cardiac tumor called hemangiosarcoma is five times higher in spayed female dogs than unspayed females, noted Kustritz. And neutered males have 2.4 times the risk of unneutered males. The risk was also higher for osteosarcoma (bone cancer): Dogs spayed or neutered before age 1 were up to two times as likely to develop the disease than those that hadn’t been altered.

Spaying and neutering may also heighten behavior problems such as aggression in some breeds and noise phobias in dogs altered at less than 5 months of age, she found.
While it’s long been believed that spaying and neutering can improve a dog’s behavior, one large study done at the University of Pennsylvania School of Veterinary Medicine found that, with a few exceptions, spaying and neutering was associated with worse behavior, although those effects were often specific to certain breeds and depended on the age at which the dog was altered.

Cats seem to fare better, though. The main risk they face from sterilization is that they can become sedentary and obese, according to Kustritz’s review of studies. As a result, vets say sterilizing cats before 6 months of age is appropriate.

Reproductive choice
Still, some oppose the mandatory spay/neuter surgery for both cats and dogs based on the grounds that pet owners may not be able to afford the surgery if reduced-cost programs aren’t available. Plus, they argue, people should have a choice.

In San Mateo, Calif., Peninsula Humane Society president Ken White says such legislation provides a one-approach answer to a problem that is different from community to community.

White believes low-cost or free spay/neuter programs are a better way to reduce the number of unwanted animals, based on what’s worked in San Mateo. The numbers of animals requiring euthanasia dropped dramatically — a 93 percent reduction since 1970 — as the humane society added ways for people to take advantage of low-cost and no-cost spay/neuter programs.

Stephanie Shain, director of outreach for the Humane Society of the United States, says that in general the organization is in favor of spay/neuter laws but “we look at every piece of legislation individually. We generally recommend that those decisions are made with a veterinarian. If an individual pet owner feels they want to wait longer or their veterinarian feels they should wait longer, that’s their choice.”

Veterinarians should consider the age for spay/neuter surgery based on the individual animal rather than rely on the traditional 6-month standard, says Khuly.

For instance, giant dog breeds are more at risk for some types of cancer, and akitas, German shepherds, golden and Labrador retrievers, Newfoundlands, poodles and Saint Bernards are among the breeds at higher risk for CCL ruptures.

“It seems that the bigger the dog, the less desirable it is to spay them early,” says Hamil. In his practice, he recommends spaying or neutering large or giant-breed dogs later than small or medium-size dogs.

Some veterinarians suggest spaying females at 12 to 14 months of age, after the growth plates have closed and between estrus cycles. Hamil says that’s not unreasonable.

A kinder cut?
Vasectomy is an option, although a rather uncommon one, for dogs that participate in sports with their owners. The main advantage is better musculature, which can help with arthritis later in life, says Khuly. A vasectomy prevents procreation but keeps testosterone production.

“I think it makes a lot more sense to consider a vasectomy,” says Khuly. “Males with their testosterone really do have some advantages over those that don’t have their testosterone.”

While experts debate the timing of spay/neuter surgery, they generally agree that the benefits outweigh the risks.

“The disadvantages, although real, are not stark,” Hamil says. “It’s not like if you neuter them they’re going to get [bone cancer]. You would have a very slight increase in incidence, and it’s going to be breed-related … [Whatever the increase is] that’s not a very big reason not to spay or neuter your dog.”

By Kim Campbell Thornton, MSNBC contributor, is an award-winning author who has written many articles and more than a dozen books about dogs and cats. She belongs to the Dog Writers Association of America and is past president of the Cat Writers Association. She shares her home in California with three Cavalier King Charles spaniels and one African ringneck parakeet.

© 2008 MSNBC Interactive

Outtake:

As legislators push for more mandatory spay and neuter laws for pets, critics are crying foul over research showing that such surgeries may raise health risks in dogs.

September 2, 2008 Posted by | Animal Rights And Awareness, Just One More Pet, Pets, Political Change | , , , , , , , , , , , , , , , , , , , , , | 8 Comments