Zeuterin, Non-surgical neutering technique


A Boon in Responsible Pet Parenthood 

There’s a new weapon in the spay-neuter effort,  a non-surgical, quick procedure for neutering dogs.  Its name is “Zeuterin,” derived from “zinc neutering.” 

Developed by Ark Sciences, Zeuterin involves injecting a concentration of zinc glutonate into each testicle.  “It’s a natural sterilizer, and it’s FDA approved,” says Cindy Scheel, executive director of Portland’s PAW Team (Portland Animal Welfare).  “Instead of the traditional castration, this is a non-invasive, non-surgical technique that is quite simple, very fast and very safe.”

The technique works for 3- to 10-month old male dogs, and a similar technique is being tested for non-surgically spaying female dogs. 

Dr. Byron Maas is medical director for Ark Sciences, a venture seeking humane solutions for animal health and overpopulation.  Dr. Maas volunteers regularly for an NGO (non-governmental organization) called Animal Balance, working to help reduce the overpopulation of animals in developing nations such as the Galapagos and Samoan Islands, the Bahamas, Dominican Republic and Cuba.

“There was a significant need to increase our ability to provide sterilization with an effective and limited budget,” says Maas.  “When we go to Galapagos, for instance, we have to fly all of our equipment there and transport everything to a small boat, then transport everything to an additional island, which is difficult.”  In addition, the volunteer team works in some locales with no electricity or running water.  Maas sought a solution to that problem and applied for a grant to start offering zinc sterilization.

The need for humane animal population control in these countries is great.  The media portrays Galapagos, for example, as a pristine National Geographic-type island of nothing but wildlife, says Maas.  But in reality, there are numerous settlements and villages.  It’s a province of Ecuador and a national park, but over the years it has been a penal colony and agriculture has introduced a lot of non-native species.  “Four of the islands have a population base on them with three airports,”  says Maas,  “and people are smuggling dogs onto the islands.  There are a lot of issues with dogs interbreeding.  If people can afford to smuggle a dog in they will, and then they set up a breeding colony of Great Danes or Cocker Spaniels.  It’s gotten to be pretty bad.”

Maas obtained competency with Zeuterin in 2009 in Mexico City, and then began offering the simple and effective procedure in other countries.  “Because of my volunteer work, Ark Sciences approached me to ask if I would be willing to consider training vets to use it,” he says.  “I said sure.  I really believe in the technology.” 

Since 2012 Maas has been a Master Trainer for Ark Sciences, training veterinarians around the country in the Zeuterin procedure.  Plans are in motion to establish a permanent training facility where vets can become certified in the procedure.

Now when Maas goes to foreign countries he has the tools to run a very effective, high-volume sterilization campaign.  “We give the dogs a light sedative and inject them and release them right then,” he says.  “And we can do that on the back of a pickup truck.  It’s very effective.”

“The dogs are given a waking sedation, kind of like when you go to the dentist,” explains PAW Team's Scheel.  After being lightly anesthetized, a patient receives a measured injection to each testicle and a quick “Z” tattoo on the groin to prove he’s been neutered.  After a shot to bring him out of the anesthesia, he is on his way home.  “After three days the Zeuterin is effective, and after 30 days it’s pretty much 100% effective,” says Scheel.

PAW Team has been utilizing the technique as it offers many advantages in serving its client base.  Comprised of low-income and homeless pet owners, clients are often challenged for transportation, and Zeuterin is less expensive than customary neutering, and does not involve surgery.  While at PAW Team, visiting dogs can also receive care such as flea treatments or nail trims.  Scheel notes that each clinic has its own fee schedule, but that generally a Zeuterin procedure costs about $30.  “It’s at least half the cost of a traditional neuter because you don’t have the surgery, you don’t have the anesthesia, and they don’t have to stay overnight,” she says.  “There are a lot of conveniences to this particular procedure.”

Maas points out that for dogs with any sort of underlying health issue such as a heart condition, surgery with anesthesia is much more risky.  Zeuterin reduces those risks, providing sterilization without additional health risks of surgery.  An added benefit to shelters is eliminating the lag time between surgery and adoption. 

“Shelters don’t have the funds to put a lot of resources into an animal,” explains Maas, “so neutering often takes place after someone picks the dog out for adoption.  This creates a couple days’ delay before the dog can go home.  Zeuterin can be done essentially in a half-hour so it frees up space and reduces the waiting time.”

Scheel points out yet one more advantage.  “Some of our clients have issues with having their dogs altered, and this is something where the animal keeps his testicles.  We have been seeing a greater acceptance of this procedure over traditional castration.” 

PAW Team serves as a Zeuterin demonstration site, hosting veterinarians and humane society representatives from all over the world.  During a clinic in June, 19 veterinarians and technicians were certified in the Zeuterin technique.

Janna O’Connor, PAW Team Clinical Director, says that while vet techs aren’t allowed to perform surgeries, “They can get certified to do this, which is just one more way to get as many dogs done as possible.  And it’s a very cool training process; very informative.”

“With Zeuterin, dogs get a very quick sedation so they don’t move or feel the pain of an injection,” O’Connor explains.  “Where a surgical neuter for a dog can take 40 minutes to an hour, with Zeuterin they are waking up and recovering in about 15 minutes.  Because it’s just injections, recovery time is fast.”

Biologically speaking, zinc is a spermicide.  After injection, spermatozoa in any stage of maturation within the seminiferous tubules— where sperm cells are produced —are killed.  When empty of spermatozoa, the tubules collapse.  Scar tissue, or fibrosis, forms in the tubules, creating a permanent, safe blockage.  According to Ark Sciences’s FAQs about Zeuterin, the technique is so targeted and precise that it renders sterile 99.6% of dogs three to 10 months old. 

O’Connor says dogs’ testicles are sore and swollen for a couple of days, so they should be kept comfortable and separate from other dogs until healing and sterilization are complete.  “The testicles shrivel a bit, but they’re still there,” she says, “which seems to be a bonus for the men who take that very personally.  Women are just happy to have their dogs back sterile.”

Patients also get a cool tattoo, which is everyone’s favorite part of the procedure, jokes O’Connor.  They also get a tag.  “At the dog park, it’s hard not to give dirty looks to the owners of dogs that still have their testicles, but with the Zeuterin technique the dogs get a tag and a tattoo!”

PAW Team is a nonprofit that provides free and very low-cost vet care to people who are homeless or living in extreme poverty.  Vets region-wide volunteer time at clinics once a month, and at outreach clinics where the homeless live, such as Dignity Village in Portland.  Scheel says next year they plan to add outreach to low-income senior housing.  “While they’re not homeless, they have fixed incomes, their pets are tremendously important to them, and they have the same challenges with getting around.”

Scheel says many people question why the homeless should have pets at all.  “We think absolutely, they should have pets.  The majority of the people we see have had things happen to them — they’ve lost their job, which has caused a cascading effect; they’ve lost their house; many of them are on the streets living out of cars or couch surfing.  These are the people who, probably more than anyone, rely on their pets for companionship.  We see people living in very rough circumstances, and their pet is their constant companion.  We believe strongly that pets are a wonderful touchstone for people.  When everything is going crazy in your life, your pet is there for you.  Zeuterin removes another barrier to being a responsible pet owner.  They want to be responsible pet owners but sometimes it’s hard.”


Vanessa Salvia's love for animals began as a child, when stray kittens just seemed to follow her home.  She now lives on a sheep farm outside of Eugene, Oregon, with a llama named Linda, a dog, a cat, a rabbit, two kids and a patient husband.