Neonatal scours can be infectious (i.e. caused by infections with infectious agents like rotavirus, E. coli or cryptosporidia) or may be nutritional (caused by sudden changes to the quality or quantity of milk fed). Regardless of the cause, rehydrating the animal is the most important treatment, and in all but the most severe cases oral electrolytes are the best way to achieve this.
It is important that oral electrolytes contain enough energy (through carbohydrates such as dextrose or lactose), electrolytes (sodium, potassium and chloride) and alkalinising agents (mainly buffers like bicarbonates or citrates) to be fully effective. Electrolyte solutions that are not in the correct balance are less effective or could even make symptoms worse.
Oral electrolytes by themselves are lower in energy than milk, so milk feeding during the scouring period should be continued as much as possible. Research shows that calves recover faster and maintain growth if they remain on a partial milk ration while they are being treated with electrolyte therapy. This is best achieved by alternating electrolyte and milk feeds and allowing ad-lib overnight access to electrolytes. For more details talk to your veterinarian.