Birth Control Goes to the Dogs

July 11, 2007 — -- Like most responsible dog owners, Crystal Ondo and Edward Wenger took their English bulldog puppy Tanqueray to the vet to get neutered when he was 6 months old.

"It was just really sad," said Ondo, a law student in Boston. "Surgery is just sad in general, and then he came out with the cone on his head. I felt really bad for him."

Tanqueray, or Tanq, is now 3 years old. He is small, puppyish and loved by his owners -- so much so that they wish they could have more of him.

"It would be great to have little Tanqs running around," said Wenger. "I'm not like most guys…it was more about his having to go into surgery."

In the future, dog owners who decide they want to breed their dogs later in life may have an option -- a removable contraceptive implant that halts testosterone and sperm production for months at a time.

The best part is it doesn't require the removal of the testicles.

The device, described in the current issue of New Scientist magazine, is called Suprelorin. It is currently available in Australia and New Zealand.Similar to a microchip, it is implanted under the skin between the shoulders.

There it slowly releases deslorelin, a hormone similar to those used to treat human prostate cancer. The hormone prevents the production of sex hormones, and the device biodegrades over time.

But preserving puppy-making potential has its price. Each implant costs between $52 and $77 and must be replaced every six months -- though Peptech, the Australian biotechnology company that makes the device, is now working on a one-year version.

Still, Suprelorin is expected to gain approval for use in the European Union in a matter of weeks, and steps are being taken to enable the drug to be sold in the United States.

Vets Weigh the Options

For some pet owners, especially men, keeping their dog "intact" -- with testicles -- is important.

"You always run into people who have an emotional attachment to their dog's testicles," said Dr. Marty Becker, a veterinarian working in Idaho.

"They think it's their dog's God-given right to have his hairy jewel bag with all the goodies in it."

Men tend to project their manly feelings onto their dogs, but women are more likely to be the caretakers for animals.

"For women, it isn't such a big deal at all," said Dr. Nicholas Dodman, program director of Animal Behavior at Tufts School of Veterinary Medicine. "They're more likely to bring the animal into the vet anyway [for neutering]."

Becker said that since 6 million unwanted dogs and cats lose their lives every year, he consistently advocates spaying and neutering. But the new implant may offer an alternative.

"You can't reverse neutering," he said. "It's the only major surgery most pets ever have. If you have this birth control thing and it gives you the option to wait, that might be a good thing."

The cost of neutering depends on the animal's size, age and the region of the country, but Becker said it averages about $75-$250 -- a onetime cost that usually ends up being a far smaller investment than the implant.

"I can see this device having a place, but for people who are sure they aren't going to breed their animals, it isn't really going to be cost-effective," Becker said.

Other vets question the efficacy of the new implant.

"Neutering is 100 percent effective," said Tufts' Dodman.

"I haven't seen any data on the efficacy of this device. Things that work on the trophic hormone [as this does] are very rarely likely to reach 100 percent efficacy."

More Versions On the Way?

The drug has been used as an alternative to surgical sterilization in female cattle, as well as elephants, lions, cheetahs, monkeys and kangaroos.

Peptech said it is working on a version for cats and female dogs.

For Wenger and Ondo, Tanq's health is more important that his manhood.

"They offered us 'neuticles' at the vet," said Ondo, referring to the synthetic testicle implants for neutered dogs.

"But I think if this thing had been around, we would have considered it for the future."