Rotaviruses are members of the family Reoviridae and are a widespread cause of diarrhea in the young of many mammalian species, including humans. The rotavirus particles are nonenveloped and possess an icosahedral symmetry. The genome consists of 11 discrete segments of linear doublestranded RNA (dsRNA) and is enclosed within a doublelayered capsid. The dsRNA fragments are numbered 1 to 11 on the basis of their order of migration during polyacrylamide gel electrophoresis (PAGE). Rotaviruses are classified into serotypes based on the specificity of the outer capsid proteins VP7 (G types) and VP4 (P types) The more common method of serotyping is on the basis of G types (13), and currently 14 G types have been identified among group A rotaviruses. Among group A bovine rotaviruses (BRVs), at least 4 G types (G1, G6, G8, G10) have been reported based on the results of enzymelinked immunosorbent assay (ELISA), virus neutralization assays, nucleic acid hybridization assays, or sequence analysis. Rotaviruses are also typed using similar procedures on the basis of VP4 specificity, and currently there are at least 4 P types of BRV (P1, P5, P11, and P12). Upon analysis by PAGE, the 11 dsRNA segments of rotaviruses produce characteristic patterns referred to as genome electropherotypes. 35 Such electrophoretic analysis of BRV isolates is useful for obtaining epidemiologic information regarding the origin of the isolates, because each isolate produces a unique pattern. There have been numerous reports of short genome electropherotypes among human rotaviruses. Most of these short electropherotypes are restricted to subgroup I and share serotype G2 specificity. All BRV isolates tested so far, regardless of genome electropherotype, belong to subgroup I, and most possess long electropherotypes.38 Recently, there have been reports of short electropherotypes among BRV isolates, all restricted to serotype G6 1,22,37 Because there have been no reports of non-G6 BRV with a short genome pattern, we wanted to investigate the possibility that BRV short pattern isolates are restricted to serotype G6, similar to the situation observed for human G2 rotaviruses. In addition, we wanted to correlate the hybridization data with serology and cross-protection studies. In this report, we describe the serologic and molecular characterization (G and P specificity) of a bovine rotavirus strain, 2292B, with a short genome pattern. The reference viruses were grown in rhesus monkey kidney (MA104) cells in roller bottles and titrated by a plaque assay as previously described. The sources and serotypes (P and