METHODS OF BREEDING 105 



SOWS and uses a pure bred sire, he has grade pigs. If 

 he uses these pigs for several generations, each time 

 using a pure bred sire, he has pigs that are called high 

 grades. For the production of pork hogs a high grade is 

 almost, perhaps practically, as good as a pure bred. Fur- 

 thermore it is true that a good grade properly selected 

 and well bred is better than a poor pure bred. 



CROSS BREEDING. 



Cross breeding consists in mating pure bred animals 

 that are of different breeds. This form of breeding as 

 practiced for the production of market hogs is advocated 

 by many as' the best form of breeding, which however 

 cannot be substantiated by evidence or by a thorough 

 study of the practice. Cross breeding, as generally prac- 

 ticed, has nothing in its favor and everything to be lost, 

 while pure breeding or grading has everything in its favor 

 to be gained and nothing to be lost. The cross bred indi- 

 vidual may be as good as the pure bred or the grade, 

 but he is no better, and where the pure bred or grade 

 may be steadily improved year after year, the cross bred 

 cannot be improved and individuals produced by such' 

 practice may even deteriorate from one year to the next. 



As an example it may be assumed that a breeder 

 through ignorance, negligence, or otherwise, may fail to 

 get good results from the practice of either pure breeding 

 or grading. He may change his policy and adopt cross 

 breeding, using the sows that he has in his herd and mat- 

 ing them with a sire of another breed. The pigs that will 

 be produced from such mating are cross bred. It is a 

 well known fact that these pigs cannot be used further 

 in the process of breeding because if cross breeding is 

 carried further than the first generation the offspring 



