METHODS OF BREEDING 111 



so wide a degree of variation as the pure bred, which has 

 already been explained, namely, that cross bred hogs 

 are more carefully selected for breeding purposes. The 

 best cross bred is equal in value for pork production to 

 the best pure bred, but is no better. The average cross 

 bred hog appears often to be a little better than the aver- 

 age pure bred. This is true only on account of selection. 

 The average pure bred as a whole, where the poorest in- 

 dividuals are used for breeding purposes, is not as good 

 as the average cross bred where the animals are more 

 closely culled. The poorest cross bred pig, however, 

 even when used for market purposes, is not much if any 

 better than the poorest pure bred. 



The last figure of the cut, No. 7, is supposed to repre- 

 sent the cross bred hog when used for breeding purposes. 

 As will be seen this is no better than the scrub. When 

 cross breeding is carried further than the first generation, 

 the individuals themselves and the results that may be 

 obtained from them are no better than hogs that are 

 scrubs. 



To gain an idea of the results that may be obtained 

 through a series of years, figures numbered 6 and 7 must 

 be considered together in comparison with figures 1 to 

 5. As previously stated, the practice of selection in grades 

 or pure breds may be followed year by year, while 

 this opportunity is entirely lacking in cross breeding 

 operations. For instance, suppose a man is producing 

 a crop of one hundred pigs either annually or semi-annu- 

 ally. One half of these, or fifty, will be female and the 

 remainder males. Of these fifty sows a few will appear 

 that belong in the upper part of the diamond-shaped 

 figure. Possibly he may have one that belongs in the 

 extreme upper point, but such a one will appear only 



