You may want to assemble your own list before reviewing mine. Go ahead, I'll wait.
OK, then. In order of importance:
- Friendliness. I love Nick dearly, but it would be nice not to have to warn people about the dangers of over-petting him. Other cats may hide from strangers, or hiss, or display various other anti-social tendencies. I suspect there's a limit as to how precisely one can breed for personality, but I don't think there's been much effort put into it, either. And I wouldn't mind if he were a bit friendlier to me, as well. Would it kill him to sit next to me on the chair when I'm reading, instead of across the room?
- Longevity. A normal human being is going to live approximately four times as long as a well-cared-for cat, assuming a cat lifetime of 20 years, which cats are certainly capable of doing. After all the emotional investment one sinks into the little furballs, the least they could do is stick around for a while. Dominic was born in the spring of 1992, so he's coming up on 16 years, by far the longest I've ever had a cat, and currently his only heath issues are vision-related. His veterinary ophthamologist says he's routinely seeing 20-year-old cats these days, which wasn't true even 10 years ago. The little cheater isn't even showing any (more) gray. In my observation, while dogs often go gray around the muzzle, cats go gray by growing in longer white guard hairs on their back and sides. Dominic has grown in the guard hairs, but they're invisible against his already-gray coat, so he doesn't look any different. He doesn't act any different, either; he hasn't slowed down appreciably. He still acts the same as he did as a six year old. Well, except now he doesn't leap down from high places like he used to, but that's almost certainly due to the fact that he's lost depth perception because his right eye is clouded by cataracts. Still, I'm almost certain to outlive him, and there's a lot of sadness in losing a pet. Having to go through that less often is definitely a good thing. Which leads to the next item on the list...
- Health. There are a lot of health-related issues that won't cut a cat's life short. Still, if Dominic's going to live to at least twenty, as I expect he will, it would be better if (for example) he weren't blind for the last few years of his life. Also, a cat that's genetically inclined to be healthier will be less expensive to own. When Nick was around four, I spent about $1500 on him dealing with kidney-related issues; putting him on special low-urine-pH-inducing food as well as a couple trips to the vet. (A big chunk of that expense was due to him coming down with blockage just a few days before I was leaving on a trip to Belgium; I had to leave him with a vet who would board pets as well, so they could treat him, watch him, and then keep him until I got back. So the dollar amount's higher than it might normally have been.) A healthier cat is a happier cat, and the owner's bank account will be happier too.
- Minimal shedding. If you own a cat, then cat fur's kind of unavoidable. I, for one, am quite unwilling to give up the experience of having a soft, cuddly, warm weight that's gently vibrating while curled up on my lap or blinking sleepily against my leg. But soft comes from fur, and fur has to be replaced, and that means shedding. But the rate of fur replacement is probably variable from cat to cat, and a cat who's follicles hold on to their hair longer before letting it go to grow a replacement would be less work for the owner.
- Capacity for learning. I first called this one "intelligence," because a smart cat is hopefully less likely to try pouncing on the moving wheels of a car, to use an example I had to deal with once upon a time. But a smart cat could also find new ways to get in trouble. What's really needed is a cat that you can train easily. One that gets the whole litter-box thing right off the bat. One that quickly grasps that a cat door that lets it out will also let it in. One that takes to heart The Lesson Of The Tuna Sandwich And Mr. Squirt-Bottle. A smart, congenial, cooperative cat. Well, as much as any cat could be, at least.
- Soft fur. While shooting for reduced shedding is more important, if possible I'd also angle for a cat who's hairs are smaller and of somewhat variable length. That will make it feel softer to the touch. Soft is nice. The combination of "healthy" and "soft fur" almost unavoidably drives my hypothetical cat to being a short-hair. Barfing up hairballs isn't as healthy as not doing so, and finer hairs will be more prone to matting and tangling, but shorter hairs are less prone to same. Also, not only does the cat have less hair to keep clean, but when it sheds, it's shedding a smaller volume of hair, contributing to "less shedding" as well.
Less important, but still things I'd breed for, include:
- Medium-small size. Specifically, a natural weight range of 6-8 pounds. Last time I went shopping for flea medication, it came in two different strengths: one for cats up to 8 lbs., one for cats over that. Dominic has weighted in around 7.5 to 8 pounds most of his life, so apparently he's a Medium-Sized Cat. He's never been overweight for his frame, which is nice as well. I've certainly met plenty of cats who were bigger, but I don't think I'd want a bigger cat, even if (especially if?) it was lean musle mass instead of fat. Nick's big enough now that I can tell when he jumps on the bed, but not so big that he's a chore to carry around. Smaller cats are going to cost a bit less to feed, make less poop to scoop, have less hair to shed, have more places to curl up and sleep, and just generally fit more easily into a human's life, I think. Not that I'm advocating weird miniature kitten-sized cats or anything! That's why I specified a range of 6-8 pounds. I think Nick's quite as big as any cat (of mine, at least) needs to be, and if he were even smaller, that wouldn't be a bad thing, either.
- Multi-colored. I'm not going for "pretty," exactly, although I think that would tend to be an indirect consequence. But a cat with spots, stripes, swirls, tipped ears or dipped toes, is not only inherently more interesting to look at, but also more easily identified. More individual. More fun.
Anyway, if I were going to breed cats, that's what I'd breed for.