  We show a conditional exactness statement for the Nisnevich Gersten complex
associated to an $\mathbb{A}^1$-invariant cohomology theory with Nisnevich
descent for smooth schemes over a Dedekind ring with only infinite residue
fields. As an application we derive a Nisnevich analogue of the Bloch-Ogus
theorem for \'etale cohomology over a henselian discrete valuation ring with
infinite residue field.
