Previous experiments demonstrated that an antigenic site responsible for virus neutralization and cell attachment was located on a 14,000-molecular-weight fragment of the major bovine rotavirus (BRV) glycoprotein (M. Sabara, J. E. Gilchrist, G. R. Hudson, and L. A. Babiuk, J. Virol. 53:58-66, 1985). However, it was necessary to investigate whether this fragment also had the ability to induce the production of neutralizing antibodies. Upon immunization of mice, the bovine serum albumin-conjugated 14,000-molecular-weight fragment, the unconjugated 14,000-molecular-weight fragment, and the native glycoprotein all induced a similar neutralizing antibody response, albeit to a lesser extent than did the infectious, whole virus. In addition, immuno-blot enzyme-linked immunosorbent assay analysis of the reactivity of anti-peptide serum versus anti-glycoprotein serum with the glycoprotein was very comparable. These results suggest that the 14,000-molecular-weight fragment may represent not only a biologically active region but also an immunodominant area of the glycoprotein.