Chile has launched a vaccine described as the first of its kind that sterilizes dogs for a year and is expected to be sold in several dozen countries.
The injection prevents sexual behavior and reproduction, offering an alternative to irreversible surgical castration, its creators say.
"This is the first vaccine of this type in the world for dogs," said Leonardo Saenz, from the University of Chile's veterinary sciences faculty.
The researcher and his team have been working since 2009 to develop the vaccine, which began to be distributed this month in the South American nation.
It stimulates antibodies and stops the production of sex hormones for a year in both male and female dogs.
"Everything is blocked: sexual activity and fertility," Saenz said.
The Egalitte vaccine has been patented in 40 countries, including the United States, Argentina, and Brazil, as well as in the European Union.
In Chile, it costs $50 a shot.
Ivan Gutierrez, a 27-year-old student, took his dog Franchesco to a veterinary clinic in Santiago to be given the injection.
"I didn't really want him to have the operation," he said.
He is not alone in having concerns about surgical castration.
"Most owners are afraid of surgery," said Mariela del Saz, the clinic's veterinarian, noting the risk of cardiorespiratory arrest.
Another method of temporary castration for dogs involves the insertion of a hormonal implant under the skin, but it "can cause side effects," Saenz said.
