§ 86. Post-mortem examination of animals. The carcass of every animal duly condemned and killed under the provisions of this article shall be examined by a veterinarian designated by the commissioner for the purpose of determining whether or not disease existed in such animal and the person making the examination shall file promptly with the commissioner a report of the examination, in a form prescribed by the commissioner; but such an examination, and the filing of such a report thereof, by an inspector of the United States government engaged in meat inspection service may be accepted by the commissioner in lieu of an examination and report by a designated veterinarian.