192 A YEAR IN AGRICULTURE 



portant measures in fighting the disease. Three methods of 

 vaccination are used in preventing the cholera: 



(1) The injection of an anti-cholera serum, which makes 

 the hogs immune only a few months or weeks. 



(2) Simultaneously with the serum is injected the defibri- 

 nated blood or virus of a diseased hog, rendering the hog 

 immune for life. 



(3) In the combination method, very seldom used, the hog 

 is vaccinated with the serum alone and ten days later the 

 simultaneous method is used. These plans of combatting the 

 hog cholera must be carried out under the direction of a 

 skilled veterinarian, and the state should supply the serum 

 to the farmer at cost. 



Markets. The successful stock man is the one who is 

 familiar with market requirements and tries to meet them. 

 Every pig club member should know something of the mar- 

 ket classes and grades of hogs. These differ somewhat 

 according to local conditions, but in a general way the 

 classification given below may be taken as a standard. 



Heavy hogs are no longer at a premium except when the 

 price of lard is high. They contain a large amount of fat. 



Butcher hogs are commonly used for fresh meat trade. 

 They are principally barrow r s. 



The term packing refers to animals which are inferior as 

 butcher hogs and are cut up, cured, and packed in boxes and 

 barrels. Mixed packing hogs are those marketed without 

 grading. 



The meat of young pigs is unsuitable for curing and sup- 

 plies part of the demand for cheap, fresh meat. 



