434 



A STUDY OF FARM ANIMALS 



sionally with crude oil and especially the sleeping quarters. 

 Hog cholera is one of the most common diseases of swine. 

 It is caused by a very minute germ. The sjonptoms of the 

 disease are general sickness, inflammation and ulceration of 

 stomach and intestines, enlargements of the glands, weak- 

 ness of the legs, causing staggering, stiffness, etc. Pigs may 

 be sick for several weeks or months before they die. A 

 large amount of 

 research work 

 has been given 

 this disease, and 

 swine plague, 

 which is much 

 the same, but 

 without satisfac- 

 tory results. In 

 recent years it 

 has been satis- 

 factorily demon- 

 strated that pigs 

 may be made 

 immune from 

 cholera by in- 

 jecting into 

 healthy animals 



a serum prepared from the blood of swine. There are two 

 methods of vaccinating, one, the "single method," in which 

 serum alone is injected into young pigs, which 

 makes them immune for 3 months or so. In the 

 other, the "simultaneous method," the serum is intro- 

 duced and, at the same time in another place, a small amount 

 of blood that has been taken from a hog sick with cholera. 

 This serum is injected under the skin of the inner thigh of a 

 pig, or behind the ear of a large hog. A large percentage 

 of the he-rds of swine given treatment to prevent cholera 



Figure 203. — Injecting serum into thigh of pig to prevent 

 cholera. Photograph from Dr. Edgerton, Ohio State 

 Veterinarian. 



