FIFTIETH ANNUAL CONVENTION 127 



than to hold them in quarantine. Of course the fact is rec- 

 ognized that in States and communities where tuberculosis 

 exists extensively the slaughtering of all reactors is im- 

 practicable. In such instances the infection can be reduced 

 on all the farms by keeping the tuberculous animals sep- 

 arate from the healthy ones. The tuberculous cattle are 

 kept under quarantine restrictions until no longer profit- 

 able; meanwhile the healthy animals are safe from the 

 danger of infection. 



The Accredited-Herd Plan — Every Cattle Owner Eligible. 



A tuberculosis-free accredited herd is one which has 

 been tuberculin tested by the subcutaneous method or any 

 other approved method under the supervision of the Bu- 

 reau of Animal Industry, or of a regularly employed veter- 

 inary inspector of the State in which co-operative tubercu- 

 losis eradication is being conducted. 



It is a herd in which no animal affected with tubercu- 

 losis has; been, found upon two annual or three semi-annual 

 tests, made as described, and by physical examination. 



.Owners of tuberculosis-free herds receive a certificate 

 issued by the bureau and the State livestock sanitary author- 

 ities. The certificate is good for one year from the date of 

 the test, unless revoked at an earlier date. 



Retesting. 



It is rather uncommon for tuberculosis to be eradicated 

 from an infected herd after one tuberculin test. After the 

 removal of reactors the herd should be retested at the ex- 

 piration of six months, and a second retest may be advisable 

 six months later, but the practice of testing herds! more fre- 

 quently than that is not usually advised. After two or three 

 semi-annual tests the herd should not be tested oftener 

 than every 12 months. While the subcutaneous test is con- 

 sidered preferable for gentle cattle, the ophthalmic and 

 intradermic methods of testing may be employed to advan- 

 tage as adjuncts to it; and it is believed that in some in- 

 stances herds may be freed of tuberculosis earlier by the 



