3/4 AGRICULTURAL BACTERIOLOGY. 



a danger of a widespread infection among such animals. Only 

 by complete isolation can he have any certainty of protecting 

 his cattle. 



The considerable trouble and expense attending such thor- 

 ough isolation of reacting animals, and the uncertainty as to its 

 results, have led in recent years to the question whether a 

 simpler method of treatment may not be nearly as useful. It 

 is recognized that, of the various factors concerned in the 

 method above outlined, the most important one is the treat- 

 ment of young cattle, and, as a result, there has been a tend- 

 ency in recent years to place most emphasis upon this factor. 

 It is said that a practical and easily applied means of treating 

 the subject does not necessarily involve an isolation of the re- 

 acting animals and the necessary expense. If the owner of 

 the herd will destroy all animals that, by clinical evidence, 

 indicate an advanced state of the disease, and all animals that 

 have any affection of the udder, he may then greatly improve 

 the condition of his herd by simply taking good care of his 

 young cattle. If the calves are allowed to drink only pasteur- 

 ized milk, or milk from non-reacting cattle, and if these calves 

 are themselves tested with tuberculin before they are allowed 

 to become members of the dairy herd, the herd can slowly be 

 built up from healthy animals and the amount of tuberculosis 

 reduced. How efficient this plan may be cannot yet be stated, 

 inasmuch as there is not as yet a sufficient amount of experi- 

 ence to warrant any deductions. At best the farmer who 

 adopts it must remember that it offers him no hope of getting 

 rid of tuberculosis from his herd. It is only a palliative 

 measure which may somewhat reduce the amount and make 

 it possible for him to preserve a herd in which the number of 

 diseased animals is comparatively small. 



It must be recognized that the success of these measures 

 will depend upon the individual farmer. Half way measures 

 are useless, and no farmer will succeed in improving his herd 



