Salmonella is endemic in modern dairy operations. Colonization of newborn calves typically occurs at birth although in-utero transmission has been reported. Most of the time when newborn calves are colonized with Salmonella spp., there are no issues with calf health with the caveat that the calves receive an adequate quantity of good quality colostrum within 2 hours of birth, they receive at least 1.5 gallons of milk or its equivalent in milk replacer each day, there is adequate space and heat or cold stress is minimized. However, not all Salmonella behave the same way in newborn calves. This report describes a very dangerous, multi-drug resistant (MDR) strain of Salmonella Heidelberg that can cause high mortality (> 25%) in well managed dairy operations. In addition, this same strain of Salmonella has a high potential to cause illness and hospitalization of calf care workers as well.