EFFORTS TO INCREASE FOOD RESOURCES 



good qualities rather than in its own appearance. Some of 

 the finest individuals were failures as breeders of desirable 

 offspring, whereas other individuals of poor appearance 

 were the progenitors of splendid specimens of the animal 

 breeder's art. Back of the poor breeders was usually noted 

 some inferior stock, while the good transmitters usually 

 came from a long line of good ancestry. 



More recently it has been realized that good ancestry 

 alone is not enough. In spite of illustrious forebears there 

 are too many "black sheep" in animal families. One way 

 to avoid undesirable offspring, science has learned, is to 

 use tested sires. If high egg-laying hens are wanted, use 

 cocks that are known to beget hens that lay many eggs. If 

 the milk yield is to be increased, it is necessary to use a bull 

 that has the ability to augment the milk yield of his 

 daughters over the yield of their dams. Basing selection 

 on progeny performance rather than upon the appearance 

 of ancestors was the next forward step in animal breeding. 



Although the best of the purebreds have desired qualities, 

 they are not so generally used in everyday farm pro- 

 duction as might reasonably be supposed. In 1920 the 

 census reported less than 1 per cent of the horses to be 

 purebred, 3 per cent of the cattle, between 1 and 2 per 

 cent of the sheep, and 33^^ per cent of the swine. Less than 

 4 per cent of all livestock in the country are purebred and 

 registered. According to Wentworth, little more than 

 half of all animals have sufficient characteristics of the 

 recognized breeds to be classed as grades from registered 

 stock. Why is there this apparent lack of appreciation of 

 the value of selected and registered livestock? Wentworth 

 says: 



"Commercially, we . . . seem to have reached certain 

 limits beyond which the methods of pure breeding are 

 not practicable. There is no question as to the improvement 

 that a purebred beef animal . . . shows over a grade 



[343] 



