Ohio Rev. Code Ann. § 2945.48

When a witness mentioned in section 2945.47 of the Revised Code is in attendance upon a court he may be placed in the jail of the county. The expenses of the officer in transporting him to and from such court, including compensation for the guard or attendant of such prisoner not exceeding the per diem salary of such guard for the time he is away from said institution, shall be allowed by the court and taxed and paid as other costs against the state.