S.D. Codified Laws § 7-9-14
In any county where the register of deeds shall have failed to make or keep proper indexes of the records of that office which by the laws of this state are required to be made or kept, or, where deterioration or destruction from any cause any such indexes become unusable or likely to become unusable by reason of continued use, the board of county commissioners shall have authority to cause such indexes to be made or copied, or cause any incompleted indexes to be completed from the records of that office and may employ competent persons for such purposes.
Such indexes when so made, or copied, or completed and when approved by the board of county commissioners shall be received and admitted in evidence in any court of competent jurisdiction in the same manner as if they had been made and kept as heretofore required by law. Any such indexes which have been heretofore so made, or copied, or completed and approved shall likewise be admissible in evidence.
SDCL 7-9-14