Vasectomised Male Cats for Contraception
- miriamm00
- Mar 7
- 4 min read
Updated: Jul 10
Entire female Burmese can drive their owners crazy calling week on, week off from as young as 20 weeks. Frequent calling can cause a deterioration of physical condition which may result in the cat failing to get pregnant later on. An early pregnancy -which would likely happen in the wild, is a recipe for problems for a cat that hasn’t yet fully grown. All of this, particularly in the vocal breeds, can be very very hard to live with!
A vasectomised Tom cat can be a fantastic solution. I really like it because it’s natural and safe for the queens. As you probably know, cats ovulate on male penile stimulation during mating which causes corpus luteum and egg to be released from the ovary. In cats, the corpus luteum maintains the pregnancy until fairly late in the gestation and then fades away and the placenta takes over for the last couple of weeks. In humans the corpus luteum only maintains the pregnancy for the first trimester – up to 12 weeks out of the full 40 -about a quarter of the pregnancy. In cats, a mating with a vasectomised stud causes the eggs and corpus luteum to be released but the eggs remain unfertilised. The corpus luteum remains in the uterus releasing pregnancy hormones and the cat stays off call -this is called a “false pregnancy”.
This technique has been used to control feral cat and ferret populations. Interestingly, the vet that operated on my cat “Tyson” had worked for a wildlife control organisation in the UK and had done hundreds of ferret vasectomies in her time. I have provided links for some scientific papers at the end of this article which talk about the technique and scientific use of this method.
Does this put the female cat at risk of pyometra? Not that we’ve noticed. The corpus luteum is creating a normal hormonal “pregnancy” environment as if the cat was actually pregnant. Unless the vasectomised male has a sexually transmitted infection there should be no difference in risk between this false pregnancy and a normal pregnancy. I don’t have scientific data to support this but in the 2 years I’ve had my vasectomised male he’s had nearly 87 matings with no cases of pyometra. In the summer we’ve noticed the false pregnancy is a bit shorter (about 40 days) but can last up to 55 days in the winter. I would be interested to hear other people’s data as I haven’t been able to find any academic research on this.
How many times do the cats have to mate to gain this effect? Again, small sample sizes but I’ve put cats in for only an hour (because another cat is coming from elsewhere for a turn!) and found that even only a couple of matings has been effective, the call was sometimes shortened and they’ve remained off call for 40-55 days depending on the time of year. This is very useful for singleton pregnancies as the mother will start to call as early as 2 weeks, an hour with the stud is enough to put her off call again for 40-55 days. You can put her in again later on until the timing’s right for a pregnancy.
Any cat breed is fine for a vasectomised stud as long as he’s healthy. You could even use a domestic shorthair. The cat behaves like an entire male so you still have to be careful about handling him. My current vasectomised male is a Burmese and he gets plenty of visitors and is not lonely.
The operation is essentially an “epididymectomy” and can take less time than a neuter in experienced hands so should cost no more than a 30 minute procedure. A vasectomy is simpler than many other operations your vet does every week so it shouldn’t matter if they’ve not done the procedure before. (I’m sure vets are like Emergency doctors: “You tube one, do one, teach one”!). Wait 6 weeks before using your vasectomised cat and be ready for an whoops pregnancy if it hasn’t quite gone to plan. Once you know he’s firing blanks you can start using him on your younger females, perpetual callers who’ve lost condition and other breeds.
I limit visitors to cats from a few breeders to reduce our exposure to any infections. We have a barter system going where Tyson is charged out per mating (10% of a stud fee) -preferably for a 2-3 day stay but some people don’t seem to want their cats back! Tyson is the busiest boy on the block!
There are lots of benefits, I’ve been able to plan pregnancies better, clear the calendar for holidays or keep a girl off call for show season -I’m lucky Tyson is gentle and doesn’t rip their necks!. Life is way less stressful without Queens on continual heat. Girls as young as 20 weeks can be mated and then safely brought back inside to spend more quality time with the family – TOP TIP: remember to diary the date of mating and when they’re likely to come back on call again to avoid a whoops mating with Mr Tabby from the paddock (true story for another day).
You can continue to show your vasectomised male as an entire cat: “Vasectomised male cats, and female cats with tubal ligation, must be shown at NZCF cat shows as males and females, respectively, in the entire section.”
There’s a well-known facebook page on pedigree cat breeding where one particular administrator shuts down any discussion on this topic. I left the group for this reason as we need to be breeding using the science to support us not trusting anecdote or woo.
Any questions? Please feel free to message me via the contacts page.
EDIT: Tyson has now been retired and will enjoy his life as a farm cat -thanks for all your help and we hope you have a happy cuddly life. Gatsby is soon to be vasectomised and will take over the baton for the team.
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