Calves with scours lose considerable water and electrolytes and dehydration is often the cause of death.
A scouring calf urgently requires water and electrolytes to correct imbalances, and must also receive a source of energy. Most scouring calves can be saved with just electrolytes, whether the cause is dietary, bacterial or viral, without the need for antibiotics.
When you give electrolytes (salts etc) the calf becomes thirsty. If you have given 6 litres of electrolytes it will go looking for another 4L of water to make up the rest of its daily requirement. Fresh clean water must be available in every pen.