There are an estimated 600 million domestic cats in the world, and 80% of them are feral or stray animals.
Spaying and neutering cats helps prevent homeless kittens and overcrowded animal shelters. Curbing feral cat populations also reduces the risk of these animals preying on wild animals, such as birds, small mammals and reptiles. Now, scientists have announced a potential new method of feline contraception that’s shown early promise: long-lasting contraceptive injections that prevent ovulation.
The impetus for the proof-of-concept study “was really to address the cat and dog overpopulation issue and the euthanasia of a lot of these animals in shelters,” said Dr. Bill Swanson, director of animal research at the Cincinnati Zoo & Botanical Garden and a co-senior and corresponding author of the study published Tuesday in the journal Nature Communications. “The best way to avoid euthanasia is not to have all these animals that don’t have homes.”
The journey to the potential new feline contraceptive method began with a discovery in the laboratory of Dr. David Pépin, an associate professor at Harvard Medical School and a molecular biologist at Massachusetts General Hospital in Boston. He and his colleagues were studying a hormone present in ovarian follicles, the layer of cells around a mammalian egg cell that nurtures its growth. To learn more about the hormone’s function, the research team injected female mice with the gene that produces it, essentially giving the mice an extra dose of the naturally occurring hormone.
“Much to our surprise, it essentially shut down most ovarian activity in rodents and made them completely infertile,” said Pépin, who was also a co-senior and corresponding author on the new study. “We thought, well, this is a very interesting tool, but what can we use it for?”
Pépin and his colleagues learned about the the Los Angeles-based nonprofit Michelson Found Animals Foundation, which supports the development of nonsurgical contraceptives for cats and dogs. “We had a tool that we knew worked in rodents, and potentially could work in these species. So it was just a matter of applying this to a new species,” Pépin said. “That’s what led us to start collaborating with Bill (Swanson).”
