24 Farmers' Bulletin 1167. 



Whether a breeder should or should not inbreed his stock is a 

 matter which he must settle for himself. The successful use of in- 

 breeding is one of the best tests of a breeder's skill, and no man should 

 inbreed unless he is confident that he possesses the requisite skill to 

 make such a step successful. Generally speaking, the inbreeding of 

 market stock is unwise; but the use of inbred males on the females 

 of such a stock may be of the highest value, provided the breeding 

 establishment which produced the males has not been injured by 

 inbreeding. Such a fact can be readily ascertained. 



Inbreeding fixes characters which can be fixed, but one of its most 

 valuable consequences is bringing clearly to light the relative merits 

 of different strains in such characters as fecundity, resistance to 

 disease, and the like, which are affected so much by factors other than 

 heredity that they can not be fixed in individuals. In these cases 

 progress is more likely to result from selection of strains than from 

 the selection of individuals. 



A real danger from inbreeding is not to be urged against the 

 practice itself, but against the peculiar infatuation which breeders 

 acquire for certain bloodlines. Once let a given line of breeding 

 demonstrate its excellence for the production of a certain valuable 

 type, and every progressive breeder strives to acquire some of this 

 valuable blood. The strain soon becomes " fashionable." From 

 this stage to breeding for the pedigree rather than for the animal 

 is an easy step which is taken much too often. The corrective for 

 such methods is the show ring, with competent and fearless judges 

 in authority. 



OUTCROSSING. 



Quite the converse of inbreeding is the practice of outbreeding or 

 outcrossing. Even in plants which are usually self-fertilized, nature 

 has provided for an occasional outcross that materially increases the 

 vigor, stamina, and general well-being of the stock. In animals 

 which have been intensely inbred, outcrossing has interesting and 

 important results. Mating to stock which has not been inbred 

 results in increases in size and vigor. A similar result also follows 

 the mating of two strains, both of which have been inbred, but which 

 are not closely related to each other. 



PURE BREEDING. 



Step by step we climb the ladder of the art of breeding until we 

 finally reach the top in the breeding of purebreds, the most fascinat- 

 ing, the most inspiring, and the most remunerative branch of animal 

 breeding when successfully followed ; the most difficult and the most 

 disappointing when not successful. The successful breeder of this 

 class of animal is far more than a business man or a farmer. He is 

 an artist, and the artistic appeal is first in importance to him. 



