SUMMARY
A virologic survey was conducted on calves with diarrhea associated with bovine rotavirus (brv) on a closed dairy farm. The brv was detected from 32 of 219 (14.6%) fecal specimens repeatedly collected from 56 calves born during the years 1992-1993, regardless of whether they had diarrhea. Most of the 32 strains were isolated from fecal specimens obtained from 2- to 6-week-old calves. After electrophoresis of double-stranded viral rna from the 32 strains, genomic rna migration patterns were similar to those of the predominant brv strains isolated at the same farm during the years 1990-1991. All representative strains were identified as G serotype 6 (G6) and P type 5 (P5) by results of the virus-neutralization test and polymerase chain reaction procedure. Thus, brv had no change in genomic rna electropherotypes and serologic antigenicities in a closed dairy herd over a period of several years.