Any time after the county board has made the original tax levy for the new county and certified the tax levy to the respective auditors, it may issue certificates of indebtedness of the new county in anticipation of the collection of the levy. Each certificate shall be in writing, signed by the chair, and attested by the recording officer of the board, mature before December 1 following the effective date of the consolidation, and bear interest at a rate as authorized under section 475.55.