An order made under section 193 of this title shall be final and conclusive unless within thirty days after service the packer or swine contractor appeals to the court of appeals for the circuit in which he has his principal place of business, by filing with the clerk of such court a written petition praying that the Secretary’s order be set aside or modified in the manner stated in the petition, together with a bond in such sum as the court may determine, conditioned that such packer or swine contractor will pay the costs of the proceedings if the court so directs.