A study of e nu + b Q-bar production, where Q-bar= b-bar, c-bar quark, at DO using e+jets events in 238 pb^-1 of integrated luminosity is presented. We select events with b quark jets by identifying secondary vertices in the jets. We interpret our findings in terms of limits on the production of particles predicted by extended technicolor models and in particular for the production decay chain rho_T -> W(-> e nu) + pi_T. In the absence of an excess over standard model background, we compute a 95% C.L. upper limit on the techniparticle production cross section for the mass combination, m(rho_T)=200 GeV/c^2 and m(pi_T)=105 GeV/c^2 of 6.4 pb. For certain values of the model parameters, we can rule out this mass combination for a range of the mass parameter M_V between 200 and 500 GeV.