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Tuberculosis testing in Oregon
Accredited veterinarian review
A review for accredited veterinarians
 
With a recent rise in the number of TB cases found on US dairies in a number of states, and the downgrade of California’s TB status, it seems a good time for a tune up on TB testing protocol. As an accredited veterinarian you must follow the guidelines below:
 
 

Handling tuberculin
Check the expiration date -
  • Store in a refrigerator   
  • Do not freeze, and avoid sunlight   
  • Do not draw up ahead of time   
  • Throw away unused portions – oxidizes quickly! 

Identification
  • Record the official identification of every animal tuberculosis tested   
  • Official identification includes an official eartag or a registration tattoo 

Injection
Use 1 ml. syringe with 26 g 3/8” needle   
  • Inject 0.1 ml. intradermally in the caudal fold – get a “bleb”!   
  • If you inject, you read (remember which side)   
  • Do not vaccinate or treat cows on injection day   
  • There is no meat or milk withdrawal time for tuberculin   

Reading the test
Palpate every injection site you injected   
  • All animals injected must be read and recorded on official forms   
  • Read the test at 72 hours post injection ± 6 hours   
  • ANY swelling is a positive response (check suspect box)   
  • Report any responders immediately to the office of the State Veterinarian and provide a  copy of the test records   
  • 1-5% false positive rate is expected - causes include M. avium subsp paratuberculosis,  M. avium, and other soil-borne Mycobacterium 
  • State/Federal veterinarians must apply the CCT test on any responders within 10 days of  injection, or must wait 60 days. 
  • Mail white and green copies to the office of the State Veterinarian within five  days of reading the test.    If you have any questions, please contact the State Veterinarian at 503-986-4680. 
 
Your efforts in carrying out effective TB surveillance are appreciated.