We have discussed tubal ligations and vasectomies for dogs and cats on this blog before with a focus on the potential benefits for puppies in shelters. National Geographic published an article yesterday on a recent study showing the potential benefits of using vasectomies to control feral cat populations.
If you are unfamiliar with tubal ligations and vasectomies for pets, here is an excellent primer. Basically they are surgical procedures to render pets incapable of reproduction and are far less invasive than traditional spay-neuter. The procedures allow pets to keep their gonads, and their hormones, and therefore do not affect breeding behavior. As such, Dr. Khuly notes that tubal ligations and vasectomies for cats are not likely to offer much benefit for owners:
They’re just not behaviorally amenable to in-home living when their ovaries and testicles hold such aggressive sway over their behavior.
But for feral cats, the implications are different:
Using a computer model, the researchers found that colonies of feral cats that were trapped, given vasectomies or hysterectomies, and released (TVHR) shrank faster than colonies that were trapped, neutered, and released (TNR), a method of feral cat control promoted by many cat advocates.
Feral cats live in groups that are controlled by a dominant male. A vasectomy cuts the tube that carries sperm without removing a cat’s testicles, so a vasectomized cat retains its sexual hormones. Thus, it can also keep its dominant position in the colony, so it’s able to mate with females without producing kittens.
Neutered feral tomcats who are returned to their colonies lose their position and another intact male takes over. Intact females are also impacted because, after mating with a vasectomized male, the female comes out of heat for 45 days which reduces the amount of time she has to become pregnant.
The study’s authors caution that the theory needs to be tested in live cat colonies to see if the computer model’s projections pan out. And there are some potentially negative ramifications as far as behavior goes – specifically tomcat spraying and fighting – which has been a selling point of traditional TNR.
My thinking is that vasectomies could be another tool in the toolbox in managing feral cat populations. TVHR might work better in rural colonies where the tomcats’ behavior is unlikely to cause complaints from residents than in urban colonies. And that’s if the computer model’s success translates to real life results.