At what age to cats stop going into heat?

Cats will go into heat into old age. As long as she's healthy it's fine to have her spayed. In fact, it's better for her. As cats get older, they become more at risk of developing a deadly uterine infection called Pyometra. Spaying her will eliminate that risk. 5-6 isn't old. Well cared for cats can live to be 20 years old. Here's an article you should read on Pyo. Go ahead and have her spayed.

http://www.sniksnak.com/cathealth/pyometra.html

edit: any vet who would refuse to spay a healthy 5-6 year old cat needs to be shut down for incompetence. Call another vet.

Try some other vets and talk to your vet personally not just the staff. It is surprising to me they think 5-6 years is so old that they would hesitate to operate, unless this cat has other known health problems that would make the anesthesia a risk. 5-6 is really not old, it's not even middle age, condidering cats usually live to around 13-18. I know cats who have been spayed at 10 yrs and did fine. And considering the other risk of pyo by her continually cycling, it seems like spaying would be the better choice. Anyway I would get some other opinions.

Cats Real Age

relies upon on the animal.... great breed canine around 9-11.... small breeds..... 10-15. cats.... 12-15. any animal over 6 or 7 often has somewhat complicated pregnancies and oftentimes lose maximum of their toddlers. animals dont provide up going into warmth until they're somewhat previous and their bodies merely won't be in a position to produce hormones anymore. often they dont stay long after this factor using undesirable physique difficulty

When they get spayed.

It's never to late to spay a cat, in fact you are benefiting them and making their life better.

It doesn't matter their age.

they will keep that way unless you get them fixed.

at the age of dead.