Decays of beauty baryons to the D 0 p h − and Λ + c h − final states (where h indicates a pion or a kaon) are studied using a data sample of p p collisions, corresponding to an integrated luminosity of 1.0     fb − 1 , collected by the LHCb detector. The Cabibbo-suppressed decays Λ 0 b → D 0 p K − and Λ 0 b → Λ + c K − are observed, and their branching fractions are measured with respect to the decays Λ 0 b → D 0 p π − and Λ 0 b → Λ + c π − . In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Ξ 0 b to the D 0 p K − final state, and a measurement of the Ξ 0 b mass is performed. Evidence of the Ξ 0 b → Λ + c K − decay is also reported.