Lesions caused by Mycobacterium bovis in the lungs and lymph nodes of sheep and goats are similar to those seen in cattle, and the organism may sometimes disseminate to other organs. Sheep and goats are quite resistant to M tuberculosis infection. The intradermal skin test is commonly used for diagnosis. The comparative tuberculin skin test conducted in the cervical region using biologically balanced purified protein derivative tuberculins of M bovis and M avium can be used to differentiate sensitization to other mycobacteria. The responses should be observed at 48 and 72 hr for induration and swelling.