Our cat loves it whyIS IT GOOD FOR CATS TO EAT BUTTER?
If your cat is also eating a good cat food, then a few licks of butter won't hurt. Just keep in mind that it should NOT make up a large part of the diet. Cat (dogs, people) will get hooked on any type junk food and it can effect their health poorly. My cat recently discovered butter, but he gets just a smear of it, once a day.
While a lick or two of butter won't harm your cat, dairy products will give many cats the runs. Cats love butter for the same as we do - it's a delicious fat.
Make sure it is unsalted ... salt is not good for them! Cat's diets are higher in fat than dog's, but even they can get too much. Certain kind of fats are very important to cats, and your cat is probably trying to get them. But, most butter is low in them. "Fail to Give Omega-3 Fats to Your Pets and You are Asking for Trouble" http://healthypets.mercola.com/sites/healthypets/archive/2009/06/13/the-frequently-missing-ingredient-in-your-pet-s-diet-that-could-devastate-their-health.aspx
It's not good but a little bit won't really hurt it but most cats can't digest dairy you only see that in cartoons but a few licks won't hurt but try avoiding it if you can. I let my dog have a spoon of vanilla n ice cream once in a while not often though
Dairy products are bad for all animals that aren't infants