I do mine in short bleats , it works great!

JRW is correct , but it depends on the vocalization you make. A repeated long drawn out bawl sends a distress signal to the nearest doe in the area , and yes , they come running in and are on loaded springs because they think a fawn is in trouble from a predator. The short bleat is more of a "mom I'm lost where are you" and brings them in at a slower more relaxed pace. I've actually had mature does call back to my bleats(probably saying I'm over here).
Do them short and maybe one every 30 seconds or so for a couple minutes and then lay off for awhile.