Incidence of diarrhea among calves after strict closure and eradication ofbovine viral diarrhea virus infection in a dairy herd

Objective-To determine whether strict closure of a dairy herd and eradicati on of bovine viral diarrhea virus (BVDV) infection would decrease incidence of diarrhea in calves during the first 31 days after birth, whether specif ic risk factors were associated with incidence of diarrhea in calves, and w hether diarrhea was associated with weight gain of the calves. Design-2-year cohort study. Animals-448 calves. Procedure-Calves were monitored from birth to 31 days of age. Fecal samples were tested for rotavirus, blood samples were tested for BVDV and antibodi es to BVDV, and serum samples were tested for IgG concentration; Risk facto rs were evaluated by means of survival analysis. Results-incidence of diarrhea in calves decreased significantly after stric t closure of the herd and eradication of BVDV infection. Risk factors for d iarrhea in calves interacted in a multifactorial way. Rotavirus infection a nd low serum IgG concentration increased the risk that carves would develop diarrhea. Carves that developed diarrhea gained significantly less weight than calves that did not develop diarrhea. Clinical Implications-To control diarrhea among carves in a dairy herd, emp hasis should be on maintaining a strictly closed herd free from BVDV infect ion. However, other measures, such as measures to prevent rotavirus infecti on and to ensure that calves. receive an appropriate amount of colostrum af ter birth, should also be-taken.