CHAPTER XII 

 CROSS-BREEDING 



THE term crossing or cross-breeding, like the term 

 in -breeding, is not capable at this time of exact definition. 

 In general we may define cross-breeding as the mating of 

 individuals which are not related. The literature of the 

 subject indicates that this term has been loosely applied. 

 Some indeed have used the term to designate the mating 

 of individuals belonging to different families within the 

 same breed. As a rule, cross-breeding means the mating 

 of individuals belonging to different breeds, as a cross 

 between the Shorthorn and Hereford; or the union of 

 animals belonging to different species, as a cross between 

 the stallion and the jennet. Cross-breeding has been 

 strongly recommended by some breeders as a valuable 

 method of improving the domestic animals. 



226. Permanent and temporary results of cross-breed- 

 ing. In recommending cross-breeding, the advocates of 

 this practice have not always been careful clearly to 

 differentiate between the permanent and lasting results 

 of cross-breeding and the more immediate and tem- 

 porary advantages. The effect of cross-breeding upon 

 the purity of the heritable characters of the breed as 

 represented by the germinal elements in the germ-plasm 

 is one thing, while the more or less temporary effect on the 

 body-cells may be quite another thing. The purpose of 

 the breeder of pure-bred registered animals is to establish 



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