186 HOG CHOLEKA 



must have his show hogs simultaneously treated 

 at least thirty days before they leave for the fairs, 

 or else he must give them serum alone at the 

 time they start, and repeat the treatment at three- 

 week intervals as long as they are on the road. 

 Neither plan is entirely free from objection, but 

 either is far from better than to neglect immun- 

 izing. If simultaneous treatment is given this 

 necessitate*, the introduction of virus on a farm 

 where there are untreated susceptible hogs, and 

 thus it is applicable only where there are facili- 

 ties for effective segregation of the show hogs. 

 If serum alone is given and the hogs are infected 

 with cholera at the fairs they must pass through 

 the resulting reaction at a time when they are low 

 in resistance, and if the reaction is so severe that 

 it results in virus excretion, there is danger that 

 in returning from the fair circuit the show hogs 

 may infect the home herd. 



If simultaneous treatment is to be given show 

 animals and the remainder of the herd is to re- 

 main susceptible to cholera, the following plan 

 is safest: isolate the show hogs in quarters that 

 will permit subsequent disinfection and give them 

 serum and virus; if during the next thirty days 

 none of the animals develop visible sickness, dip 

 or spray them thoroughly, using 3 per cent com- 

 pound cresol solution, and send them out on the 

 show circuit; when they return, it is best to dip 



