State Dairy Association. 379 



duced like, but some cows, even then, were undoubtedly better 

 milkers than others, due to the law of natural variation. The prin- 

 ciple of selection did not come in to retain this variation, and no 

 improvement in this characteristic was made. 



After cattle were domesticated, the same conditions existed, 

 but finally man began taking advantage of the natural variations 

 and began saving breeding stock from those having the charac- 

 teristics, such as greater milk production, which he found to be 

 valuable. 



The animal which is different from the others of its kind by 

 natural variation will reproduce this characteristic in a certain 

 proportion of its descendents. If this same natural variation is in 

 the ancestry of both parents, the chance of transmission is much 

 greater, but under any circumstances only a part of the progeny 

 will have the new characteristic. 



The dairy cow of today is largely an artificial product, or, per- 

 haps it would be better to say, she is an abnormality, since her 

 mammary glands have been abnormally developed by taking ad- 

 vantage of the law of natural variation. 



The rule of "like produces like" is only true to a limited ex- 

 tent, and the farther we get away from the original type in breed- 

 ing the smaller the proportion of cases where it holds good. This 

 accounts for the fact often observed that the offspring of a phe- 

 nominal cow are often disappointing. However, it will be found 

 that on the average there will be more good animals among the off- 

 spring of such a cow than among those from a cow of moderate, 

 or low dairy capacity. We must always expect to find inferior ani- 

 mals appearing frequently in all herds. No breeder can prevent it, 

 but no good breeder fails to reject the inferior ones promptly when 

 discovered. The higher developed we get our cows, the more diffi- 

 culty we must expect in keeping them all up to the standard. 



In selecting a bull for a mixed herd, or one of low dairy ca- 

 pacity, any well-bred bull of a dairy breed with good producing 

 individuals behind him is certain to benefit the herd. Even for the 

 grade herd, the exceptional bull that will transmit qualities higher 

 than the average of his breed is worth more than two or three in- 

 ferior ones. 



There are two courses open to the man selecting a herd bull : 

 One is to buy a young bull on the strength of the records of his 

 ancestors and trust to luck to a certain extent that he will be one 

 that will transmit the desirable characteristics of his ancestors to a 

 high degree. As a rule such a bull will do fairly well, at least in 



