The first thing to do is to stabilize any sick calves. The most important treatment is fluid support. Oral calf electrolytes are usually adequate in rehydrating mildly affected calves; however, intravenous fluids are sometimes needed. The most common causes of calf diarrhea are viral and protozoal, which are resistant to antibiotic therapy, so antibiotics are not always needed. There are also noninfectious causes of calf diarrhea. Sanitation is a key preventive management tool used to control the spread of diarrhea/scours.
Next, segregating animals into groups is needed to break the cycle of transmission. Sick calves should be left on the contaminated pasture. Pregnant cows should be moved to a clean pasture. Healthy calves should be left with the sick calves unless a third pasture is available. Calves that are healthy today but already exposed may be incubating the disease and can break out with diarrhea later and contaminate other pastures. Large herds can segregate calves by age, keeping older calves away from younger calves.
Finally, a proper diagnosis of the cause of diarrhea is needed so treatment and preventive strategies can be determined. There are some specific treatments and vaccinations available for calves that help in the short term. There are also vaccines for the cows that provide immunity to the calves through colostrum in the long term. Nutrition of the cow plays a major role in calf health, and nutritional deficiencies can make calves more susceptible to calf diarrhea.
Consult a veterinarian for help with control, treatment, and determining specific causes of calf diarrhea.