Rota viruses and Corona viruses are among the world's most widespread diarrheal pathogens in the calf area, they occur ubiquitously. They invade the enterocytes and destroy them. Diseases in adult animals proceed subclinical. Even in heavily with Rota and Corona virus polluted farms, the colostrum of dams contain little maternal antibody, if there has been no viable dam vaccination before calving.
With high infection pressure, the calves become ill as early as 12 - 72 hours post partum. It comes to mushy to watery diarrhea. The disturbance of the general condition depends strongly on the degree of the enteritis and of the excisting exsiccosis. In dramatic cases, it leads to permanent lying and death of calves. For this reason a rapid and timely diagnosis is essential to prevent heavy losses and the spread in stocks.