502 IOWA DEPARTMENT OF AGRICULTURE 



Bovovaccine by what it known as the Von Behring method is 

 therefore in the experimental stage, so far as practical results are 

 concerned, although some good breeders have tried it with satis- 

 factory results. Mr. E. B. Young, of Buffalo Center, vaccinated 

 thirty animals. None reacted to the tuberculin test. These were 

 calves of pure bred cows, some of which had reacted to the tuber- 

 culin test, and had been allowed to mingle with the diseased ani- 

 mals. Von Behring has obtained a product known as tulose from 

 tubercle bacteria, with which he has succeeded in immunizing 

 against living tubercle organisms. This method is known as Mi- 

 thridatization. He holds that a passive immunity may be obtained 

 from the use of serums. The principal value of immunization lies 

 in making it possible by saving the calves to build up a sound herd 

 from tuberculous stock. 



Considerable attention has been given to the herds at the various 

 state institutions. The appended report sheet will show the tests 

 and the variation in the results growing out of a number of suc- 

 cessive tests in some instances. With some few exceptions, the 

 successive tests show a diminution of the extent of infection, and 

 the eradication of the disease under the preventive and sanitary 

 measures enforced. The tests were not made uniformly at all the 

 state institutions, but were made at different times and at unequal 

 intervals. 



The state herd at Independence was tested by this department 

 on May 28. 1909. The herd then numbered eighty-nine, out of 

 which number fifty-one reacted. An addition of forty-four head 

 had been made to the state herd since the preceding test, which 

 had been bought in Binghamton. N. Y. Of these animals twenty- 

 three reacted in the test mentioned. The attached post mortem 

 sheet discloses the condition of the individual animals, as they 

 were slaughtered at the packing plant. Again in December, 1909, 

 the herd, then numbering fifty-four head, was tested, and six 

 found to react with two suspicious. Post mortem record of these 

 eight animals is appended to this report. The herd, forty-three 

 in number, was once more tested in May, 1910, and no reactors 

 found. It is therefore assumed that the disease had been stamped 

 out in this institution, though stringent precautions are being 

 observed to prevent a re-infection. This condition is gratifying 

 in view of the fact that in the test made as reported in the Sixth 

 Biennial Keport of this department, when the state herd con- 

 sisted of one hundred and seventy-six animals, one hundred and 



