You need to get oral electrolytes in the calves as soon as scours and dehydration occur. If the calf has a fever, you will need veterinarian intervention. It appears it was too late with the IV electrolytes on the calf that died. Keep the calf warm also (in the winter).
Unfortunately, calves taken to the auction are those often not given appropriate attention at birth or administered colostrum in a timely manner. Buyer beware; if possible, know the source.
Mike Hutjens, Extension Dairy Specialist, University of Illinois - Illini DairyNET
J.W. Schroeder, North Dakota State University Dairy Extension