I agree with flacowman. Instead of using drugs (which generally do not work and many are used illegally) expose your calf to EVERYTHING at home in a safe environment. Play a loud radio, have kids run around, pop balloons, drive by them with tractors and 4 wheelers. Walk by them with ballloons. Basically do anything that is new to the calf. Do it slowly enough not to freak out the calf, but sudden enough to "spook" it, so it realizes that even if it is new and scary, it will no hurt them and the calf learns not to be skiddish. It will be slow process so I hope this isn't a "the show is next week and we just got the calf in" type of situation.
Also, keep in mind, some calves just will not calm down. Some just have that nervous gene/attitude and just do not make good show calves. If that is the case, I would recommend you accept that idea and do not show the calf. Please do not risk getting anyone hurt. It honestly isn't worth it.