4 98 IOWA DEPARTMENT OF AGRICULTURE 



ease) may toe marked and held for the test later after such disqualifica- 

 tion shall have passed. 



17. The operator must bear in mind the possibility of transferring 

 other diseases from animal to animal by contact, by the use of hypo- 

 dermic needle on two in succession, and above all by the clinical ther- 

 mometer. Diseases like contagious abortion, which present no obvious 

 symptoms in the intervals, are especially liable to be carried in this way, 

 and instances of the active extension of this after a test, have come 

 under my notice. The operator should always inquire carefully as to 

 the existence of abortions and sterility in the herd, put the aborting 

 animals by themselves, using a special thermometer upon them, ana 

 carefully washing the hands before going to other animals. It is well 

 further to clean the thermometer after each animal and disinfect it 

 with carbolic acid solution (5:100). 



Of the usual American preparation 2cc. (30 drops) is adapted to a 

 cow or ox of 1,000 to 1,200 pounds. For larger or smaller animals a 

 moderate increase or reduction must be made, yet a considerable lati- 

 tude is allowable. 



We recommend the use of tuberculin manufactured by the Bureau of 

 Animal Industry. 



Healthy herds should be protected by preventing infected ani- 

 mals from being brought into the herd. Animals exhibiting tuber- 

 culous udders and giving evidence of generalized tuberculosis should 

 be eliminated. Prompt tests should be applied, and reacting ani- 

 mals should be at once segregated. The test should be repeated, 

 at intervals, until all infected animals are discovered and re- 

 moved. 



Animals that react to the tuberculin test should be disposed of 

 in one of the following ways : Destruction, slaughter for beef 

 under inspection, or isolation for breeding purposes according to 

 the Bang method. No animal that has reacted to the test should 

 ever be returned to the sound herd, even though subsequently 

 ceasing to react and appearing to be perfectly well. Unless cows 

 can be purchased from perfectly healthy herds, it is inadvisable 

 to continue or establish the practice of selling cows during dry 

 season and buying fresh cows. No cows should be bought for dairy 

 purposes unless they pass the tuberculin test. All new animals, 

 not reacting, should be retested at intervals. 



Aside from the public health aspect of the subject, tuberculous 

 cattle entail loss to owners in the following ways : Death from the 

 disease after it has become established ; waste in feeding, as dis- 

 eased stock cannot utilize the full value of foods ; heavy loss through 

 infection of other animals, including hogs, vast numbers of which 

 are annually made victims of tuberculosis ; reduction in the market 



