Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at $\sqrt{s} = 8$ $,\text {TeV}$ in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either $\mathrm {W}\rightarrow \mathrm {e}\nu $ , $\mathrm {\mu }\nu $ or $\mathrm {Z}\rightarrow \mathrm {e}^+\mathrm {e}^-$ , $\mathrm {\mu ^+}\mathrm {\mu ^-}$ , or ${\nu }\overline{\nu }$ ). The results are based on data corresponding to an integrated luminosity of 18.9 fb$^{-1}$ collected with the CMS detector at the Large Hadron Collider. The measured cross sections, $\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm {W}\mathrm {Z}) = 30.7 \pm 9.3,\text {(stat.)} \pm 7.1,\text {(syst.)} \pm 4.1,\text {(th.)} \pm 1.0,\text {(lum.)} ,\text {pb} $ and $\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm {Z}\mathrm {Z}) = 6.5 \pm 1.7,\text {(stat.)} \pm 1.0,\text {(syst.)} \pm 0.9,\text {(th.)} \pm 0.2,\text {(lum.)} ,\text {pb} $ , are consistent with next-to-leading order quantum chromodynamics calculations.