228 FARM ANIMALS 



is sometimes made for the razorback animal 

 that he is more resistant to hog cholera and other 

 infectious diseases than pure breeds. This matter, 

 however, is a doubtful point. It has not been 

 shown by experiments and it appears that if pure 

 breeds are properly fed and allowed exercise 

 under sanitary conditions that no great difference 

 in susceptibility to infectious diseases can be 

 observed between the pure breeds and razor- 

 backs. 



When it comes to a comparison of different 

 pure breeds great difference of opinion prevails, 

 depending on the particular purpose for which 

 the breed is raised. On the basis of the experience 

 of Canadian hog raisers it appears that in economy 

 of gain the pure breeds stand in the following 

 order: Berkshire, Tamworth, Yorkshire, Duroc 

 Jersey, Chester White; while for the production 

 of bacon the breeds stand in the order, Yorkshire, 

 Tamworth, Berkshire, Chester White, Duroc Jer- 

 sey and Poland China. In a feeding period of 

 four months, the Canadians found the greatest 

 gain in the Yorkshire and the least in the Tam- 

 worth. The relative position in which the breeds 

 stand in different tests is, however, not always 

 the same as shown by experiments at different 

 times by the same feeder. The Yorkshire and 

 Tamworth are obviously the best breeds for the 

 production of bacon for export while in most tests 

 the Berkshire seems to be at the top in economy 

 with which feed is utilized. A number of cross- 

 bred hogs have been found to be very desirable 

 for the production of bacon. Thus, crosses 

 between the Tamworth and the Poland China 

 are very fine animals for this purpose. In fact, 

 according to many experiments, crosses appear 



