Section 50.4 - Classification of cattle, bison, captive cervids, and other livestock as infected, exposed, or suspect(a) Cattle, bison, and captive cervids are classified as infected with tuberculosis on the basis of an intradermal tuberculin test applied by a Federal, State, or an accredited veterinarian or by other diagnostic procedure approved in advance by the Administrator.(b) Cattle, bison, and captive cervids are classified as exposed to tuberculosis when such cattle, bison, and captive cervids(1) are part of a known infected herd, or(2) are found to have moved from an infected herd before the time infection was disclosed in such herd and after the time such herd had apparently become infected, or(3) are found to have been exposed by virtue of nursing a reactor dam: Provided, That cattle, bison, and captive cervids classified as exposed to tuberculosis shall be removed direct to slaughter.(c) Cattle and bison are classified as suspects for tuberculosis based on a positive response to an official tuberculin test, in accordance with the "Uniform Methods and Rules-Bovine Tuberculosis Eradication" (incorporated into the regulations by reference in part 77). Captive cervids are classified as suspects for tuberculosis in the same manner as cattle and bison.(d) The designated tuberculosis epidemiologist will determine whether livestock other than cattle, bison, or captive cervids are classified as exposed to tuberculosis by reason of association with an affected herd of cattle, bison, or captive cervids.40 FR 27009, June 26, 1975, as amended at 52 FR 39614, Oct. 23, 1987; 56 FR 36998, Aug. 2, 1991; 60 FR 37809, July 24, 1995; 63 FR 34264, June 24, 1998; 67 FR 7591 , Feb. 20, 2002