I've had maybe 50 calves from sale barns over the years - my course of action has always been 2 days of colostrum, then Dairy Maid milk replacer twice daily, and Entrolyte H.E. (Southern States) twice daily for 2 wks., then just the milk replacer - I've only lost 2 calves. Seems to work. Had a few get the white snotty discharge - I stayed the same course with all of them, they did fine. Sometimes putting too much medication in them is just as bad and none at all. Even if they had scours, I still gave them the milk replacer along with the electolytes solution, scours usually gone before 2 wks were up.