126 HOG CHOLERA 



be immunized, the sow should be tied and injected 

 first, and released only after the pigs have been 

 vaccinated. 



Another method of confining large hogs is to 

 connect two pens with a narrow, low chute, which 

 can be closed at both ends. Into this a limited 

 number of hogs are crowded tightly as they pass 

 from one pen to the other, and the operator may 

 reach over the side of the chute and inject the 

 animals behind the ear. This involves some labor 

 in preparation, but it is a rapid method of han- 

 dling, and may be serviceable when a large num- 

 ber of hogs are to be immunized. Quiet hogs may 

 sometimes be injected without resorting to noose 

 or holder as the operation is by no means painful. 



Methods of Using Serum 



Preventive vaccination against hog cholera in- 

 volves the use of just two materials; anti-hog- 

 cholera serum, which is protective in nature, and 

 which is prepared from the blood of hogs that are 

 hyperimmune to cholera; and hog cholera virus 

 which is the defibrinated and preserved blood of 

 pigs that are suffering with hog cholera at the 

 time bleeding takes place. With these two ma- 

 terials three methods of immunizing have been 

 developed; serum alone, simultaneous (double, or 

 serum- virus), and follow-up, which is a combina- 

 tion of the two first-named methods. 



