Recognizing the symptoms and acting fast is usually the only way save a calf when toxins take over its gut. Heather Smith Thomas writes about this fatal condition and the urgency required to save a calf before it goes into shock.
A calf may die of scours and dehydration with a viral intestinal disease, but some bacteria produce deadly toxins that affect the calf more acutely.
Source: Angus Beef Bulletin, January 20, 2021. Link.