vytnas, we use whole milk keifer for every recipe that calls for buttermilk. It works great. It has a nice thick consistency and a good tangy flavor.
Lifeway is a local company whose keifer is available almost everywhere in this area. The trick is to find a place that stocks the "whole milk" kind, unflavored. This is called "Lifeway Original".
It's my understanding that Lifeway ships mixed boxes -- say 9 or 12 quarts in a box or something like that -- a mix of the different fruit flavors and full-fat, low-fat or fat free. If your local store carries Lifeway keifer, ask the manager to tell Lifeway to include the "Original" in the mix and it should show up.
Or you can find it fairly reliably at Produce World, Jerry's, Tony's, Marketplace on Oakton etc.
We use it for pancakes, muffins, anything baked, "buttermilk'-marinated fried chicken and more. Try it! --Joy