434 DISEASES OF SWINE 



The results of the disease in the untreated shoat and the suck- 

 ing pigs leaves no question as to the virulency of the outbreak in 

 this particular case. The disease here, as in the other herds which 

 have been described, was of the usual severe and extremely fatal 

 type. But for the injection of the serum on this farm the total 

 death loss would have undoubtedly been almost the entire herd. 



In this instance we again get a suggestion as to the proper 

 method of administering treatment. In this herd there were no 

 visible evidences of cholera at the time of treatment, and on this 

 account the double or serum-simultaneous method of treatment 

 was used. In this way not only were the swine protected against 

 the epidemic then present in the neighborhood, but there was also 

 the establishment of a permanent immunity which will last 

 throughout the lifetime of the animals. Had temperatures been 

 taken many of those apparently well would have been found sick, 

 and in those cases serum alone in large dosage should have been 

 given. 



It is by the use of this method of treatment that we may hope 

 eventually to control and even eradicate hog-cholera. If we 

 estabhsh a permanent immunity in this herd, these animals will 

 not be susceptible to infection next year, and it has also been 

 quite definitely found that pigs born from immune sows have 

 a more or less strong immunity which persists as long as they are 

 still sucking. In these cases the protection is probably in a meas- 

 ure due to immune bodies which are transferred from the mother 

 through the milk. If these pigs are then simultaneously treated 

 about the time of weaning we will estabhsh in them a permanent 

 immunity, and in this way we will gradually build up in each dis- 

 trict herds of immune hogs. In this manner we remove the pos- 

 sibility of cholera developing on this farm, and make just one less 

 possible source for outbreak the following year. Through this 

 method of procedure we will finally succeed in establishing such 

 conditions throughout the country that outbreaks of cholera 

 will be few and widely scattered, and easily stamped out before 

 they have gained any such headway as is now seen every year in 

 the Corn-belt States. 



Herd Number Five. — This herd was located in the south- 

 east quarter of Section 35, Grant Township. It was first seen 



