190 THE farmer's VETERINARlAK 



the owner must decide as to just what he will do in 

 the way of disinfection and cleaning up, or whether 

 he will stay out of the hog business for a year and 

 allow the infection to die out. This is, of course, 

 without regard for the possibility of putting in 

 vaccinated and immune hogs. Feeding troughs and 

 feeding floors and the hog house in general, may be 

 disinfected if of reasonably good construction, by a 

 thorough cleaning and then by one of the methods 

 suggested under prevention. If the sick hogs have 

 been kept in an old straw shed or in an old hog 

 house that is about ready to fall down anyway, by 

 all means the best method of disinfection is by 

 burning. Without disinfection or burning the 

 owner cannot be safe in putting in susceptible hogs 

 within much less than a year after the last hog died 

 or recovered. The slow old chronic cases that go 

 dragging around at the end of an outbreak should 

 usually be killed and safely buried, for it is rarely 

 profitable to put such hogs in shape for market. 

 It might possibly be worth while to hold such a 

 one over and nurse them along, in case of valuable 

 brood sows, for hogs having recovered from cholera 

 are usually immune for life. 



Brood sows which have had the disease and re- 

 covered usually give something more than natural 

 immunity to their offspring. But the degree of 

 immunity so conferred is so variable in degree and 

 uncertain otherwise that it cannot be depended 

 upon as a routine method of establishing immune 

 herds. Yards may be practically disinfected by 

 plowing or by burning off a good layer of straw. 



Hog Cholera Vaccination. — Generally stated, this 

 vaccine consists of two parts: (a) Blood serum 

 from the body of a specially immunized hog; and 

 (b) virulent blood serum from the body of a hog 



