  We measure the ratio of cross sections, $\sigma(p\bar{p}\rightarrow
Z+2~b~\text{jets})$/$\sigma(p\bar{p}\rightarrow Z+\text{2 jets})$, for
associated production of a $Z$ boson with at least two jets with transverse
momentum $p_T^{\rm jet} > 20$ GeV and pseudorapidity $|\eta^{\rm jet}| < 2.5$.
This measurement uses data corresponding to an integrated luminosity of 9.7
fb$^{-1}$ collected by the \DO experiment in Run II of Fermilab's Tevatron
\ppbar Collider at a center-of-mass energy of 1.96 TeV. The measured integrated
ratio of
$0.0236\pm0.0032\left(\mbox{stat}\right)\pm0.0035\left(\mbox{syst}\right)$ is
in agreement with predictions from next-to-leading-order perturbative QCD and
the Monte Carlo event generators {\sc pythia} and {\sc alpgen}.
