Johne's Certified Veterinarians must provide Johne's risk assessments and 

 develop herd-management plans and collect and submit samples according to the 

 program requirements. 



For information on Johne's Certified Veterinarian training in your State, please 

 contact your State animal health official or the APHIS-VS Area Office nearest you. 

 For further information on the Voluntary Bovine Johne's Disease Control Program, 

 please go to http://v\nvw.aphis. usda.gov/vs/nahps/johnes on the Web. 



Prevention 



For herds that are not infected, managers should take precautions against 

 introduction of Johne's disease. Such precautions include keeping a closed herd or 

 requiring that replacement animals come from test-negative herds. Some States offer 

 Johne's certification to test-negative herds. The new Uniform Program Standards for 

 the Voluntary Bovine Johne's Disease Control Program (APHIS 91-45-014) oudine 

 a new, voluntary national Johne's classification program that helps to identify risk of 

 infection in participating herds. The Johne's Program Standards can be found on the 

 Web at <http://www.aphis.usda.gov/vs/nahps/johnes-umr.pdf>. 



The key to preventing johne's infection is to know that 



• Herds get infected only when infected cattle are added to the herd; 



• Prepurchase testing for Johne's disease is today's standard of \'eterinary 

 practice; and 



• Testing the herd of origin is much more reliable than testing only the 

 purchased cattle. 



Table 2 outlines options (in order of decreasing risk) of buying M. avium subsp. 

 paratiibcrcidosis-infectcd animals. 



Table 2 — Johne's disease testing options and the risk of buying cattle 



1 "" ■ ■ 



Options ; Risk 



No testing. 



Very risky — 10 percent chance of purchased 

 animal being an M. parafubercu/os/s-infected cow. 



ELISA-test the individual animal before purchase; do 

 not purchase anything from herds with cows suspect or 

 positive by ELISA. 



Slightly less risky than not testing; more confidence in 

 negative tests on older animals, not heifers. 



Quarantine and test after purchase: ELISA positive — 

 culture twice at 6-month intervals. 



Lowers risk and is sound policy for several infectious 

 diseases of cattle. 



Partial test on herd of origin: ELISA on 30 lactation or 

 older cows. 



Low risk of Johne's disease in any animal from such 

 herds but not percent. 



Whole-herd ELISA-test herd of origin. 



Very low risk of Johne's disease if herd tests 100- 

 percent ELISA negative or culture negative. 



Purchase only from certified-free herds. 



No risk of Johne's disease. 



2-26 



