Greetings!
I've been playing DF for a while, off and on.. a lot of off, admittedly, but darn, it's enjoyable coming back after each major revision and going, "Tons of new features and fixes, whee!".
One problem that has plagued me an' others is the cats. Now, mind you, I adore cats. I do. Which makes the magma baths to save the fortress' FPS really hard. Then I thought to myself, as I started blatently cheating via smelter reactions.. why can't I meddle with the cats data? Get rid of kittens?
.. That was no go, since they're the same species. Then after eyeballing the creature token list on the wiki, I found it. [NO_GENDER]. Added to the cats file in Creature_Domestic.txt, it effectively fixes all cats. Everywhere. I brought a pair with me, and after three years, they did not breed, they did not sire kittens.. and oddly enough, they also didn't pick an "owners" to hypnotize. But they did thier proper vermin killing job nicely, and let me have a few cats wandering my fortress again, without fear of FPS death. A quick search on this topic didn't show anyone elses mention of the idea.. so.. there you are. To summarize.
/Raws/Objects/Creature_Domestic.txt
Added [NO_GENDER] on it's own line right after the [PET] line for CREATURE:CAT.
Try it out, maybe it'll work just as smooth for you. Maybe someone will come up with a mod to toggle the flag off on cats and have them till then be normal. Yanno. An option to "Fix" your cats. ^_^
- Shirra