50 Missouri Agricultural Report. 



during immune blood. The amount of blood drawn from different 

 hogs differs, but is always comparatively small. The amount of 

 the serum to be injected into the hog to be immunized is not set- 

 tled positively, but good results have been gotten by injecting 20cc 

 or 5 teaspoonsful with 1 to 2 cc. of the culture. The operation 

 of immunizing a hog may be performed with the use of an ordi- 

 nary blackleg syringe, and is not more difficult than preparing and 

 administering blackleg vaccine. The principle hindrance to the gen- 

 eral use of the immunizing method is the difficulty of getting the 

 necessary amount of serum from immune hogs. If it is possible to 

 produce a suitable serum in hogs, in which case much larger quanti- 

 ties may be procured, the method may be put into general practice. 

 Unless this can be done, the process of immunizing must of neces- 

 sity be too slow for general use in a wide spread outbreak of hog 

 cholera. Even now, the use of this method is of the greatest value, 

 laying the foundation for breeding hogs immune from cholera. 



BREEDING HOGS IMMUNE FROM CHOLERA. 



It was demonstrated some years ago by Dr. A. T. Peters, of 

 the Nebraska Experiment Station, that by beginning with immune 

 sows, hogs could be bred immune from cholera. The method has 

 been successfully followed by farmers in this State. There is no 

 room for doubt about the success of the method. The only diffi- 

 culty will be to get hog raisers to put it into general practice. 



This method consists in beginning with immunized sows and 

 feeding them the germs of hog cholera once, two weeks before 

 and twice at intervals of two weeks after farrowing. Immune sows 

 with which to begin this method may be secured in two ways: 

 (1) By selecting hogs that have gone through an outbreak of the 

 cholera and either recovered or did not take it; (2) by immunizing 

 sows artificially as explained above. The germs with which to 

 feed the sows under treatment, are present in the flesh of a hog 

 which has died of cholera and this flesh may be used. It is some- 

 times very difficult to obtain the flesh of a diseased hog. On that 

 account it will be necessary to use an artificial culture. The au- 

 thorities of the Missouri Experiment Station have agreed to keep 

 a culture of hog cholera germs and send out supplies to those who 

 desire to make use of this method. 



