(a) Any employee of USDA who attends a judicial or administrative proceeding as a witness in order to testify or produce official documents on behalf of the United States is entitled to travel expenses in connection with such appearance in accordance with the Agriculture Travel Regulations.

(b) An employee of USDA who attends a judicial or administrative proceeding on behalf of the United States is not entitled to receive fees for such attendance.

(c) An employee of USDA who attends a judicial or administrative proceeding on behalf of a party other than the United States when such appearance is in his or her official capacity or arises out of or relates to his or her employment with USDA is entitled to travel expenses in accordance with the Agriculture Travel Regulations to the extent that such expenses are not paid for by the court, agency, or official compelling his or her appearance or by the party on whose behalf he or she appears.

(d) An employee of USDA who attends a judicial or administrative proceeding on behalf of a party other than the United States when such appearance is in his or her official capacity or arises out of or relates to his or her employment with USDA is required to collect the authorized fees for such service and remit such fees to his or her USDA agency.