Here, the recommended scour treatment is sour boluses such as Calf Span (three day treatment) and a sulfa injectable like trimidox or trivetrin along with flunazine as an anti inflamatory, as well as a drench of electrolytes
Most scours are viruses so any treatment of drugs only prevent secondary infection not treat scours. The drench of electrolytes is what really does the trick.
That said, we have noticed a great great reduction in scours and scour treatments with doing ML scour vaccines in the last trimester (booster shot). Now treatments are only done if...
...the calf gets the staggers, or goes down
...the calf stops sucking
This year, we got hit with a massive snow storm. Normally that would bring about massive scour treatments. However, after several years of vaccinations and taking the wait and see approach, we waited it out. Calves got the squirts, still sucked the cow (not as much, but still 2 quarters), and still a bit fiesty. We give the calves 24 hours to show improvement, bed them down in different areas to reduce the virus loads, and let then $ in vaccinations do the work.
Our vet is a firm believer in scours being a 90%+ management issue. Management includes but not limited to clean bedding, good passive transfer of colostrum, lots of space, little crowding, and a good biosecurity program. Meaning, no one goes into the cow/calf or calving area if they have been on another farm without clean coveralls, clean disinfected boots. No other farm vehicles are allowed passed the home yard except the vet, and even she makes sure that truck of hers is clean and she uses clean boots and coveralls.