They should know what EPD's are and what they are used far, definately know the sire and dam of your calf, anatomy of the calf, breed characteristics, I sometimes ask them to give me examples of 3 breeds in each category American, British, European, these days its not uncommon to hear questions from some judges about TH/PHA, i have been asked difference between Bos indicus and Bos taurus, definately know that cattle are ruminants, have 4 stomach compartments and what they are in more advanced classes. Pretty much if a judge is going to get really advanced with questions, anything cattle related is fair game.