7 C.F.R. § 1.428
(a) Motion for taking deposition. Upon the motion of a party to the proceeding, the Judge may, at any time after the filing of the submission, order the taking of testimony by deposition. The Motion shall be in writing, shall be filed with the Hearing Clerk, and shall set forth:
(b) Judge's order for taking deposition.
(1) If the Judge finds that testimony may not be otherwise available at the hearing, the taking of the deposition may be ordered. The order shall be served upon the parties, and shall state:
(d) Procedure on examinations.
(f) Corrections to the transcript.