Ok say the sale starts at noon and ends at 8pm, so you call at 3pm and there is already 4 bids on the calf, say it started at 1,000 and by the time you got to her it was 4,000, ok well say no one else bids onit and whne 8pm comes around they do a a "call back" and call back every person that has bid on a calf, so they call the first person that bid on the calf and tell them where its at and they can bid higher or say no, and so on and so forth its basicly a very long bidding process, hope that helps