I prefer to give an acidophilus supplement, not yogurt. The one that I use is human supplement made by Webber Naturals.http://www.zooscape.com/cgi-bin/mait...n/questp100025
It is a non-dairy supplement. The pills are in little capsules that I break apart and sprinkle on their food. I'm not sure what it tastes like, but it's not horrible. They will also take it if I mix it in about a tablespoon of water. They lap it up happily.
I usually give them each half a capsule. There is no risk of giving them too much. If you can't find that brand, look for something similar...they are fairly common in drugstores.
Probiotics are especially important during antibiotic administration. Make sure that you allow at least 3 hours before or after the meds to give the probiotic. Otherwise, the antibiotic will kill the probiotic as well...making your efforts useless.